In this detailed training session, Matthew Taylor breaks down the critical aspects of evaporator airflow in commercial refrigeration systems. Learn about: The importance of fins per inch in refrigeration vs. AC systems How frost accumulation impacts coil design and performance The relationship between humidity levels and defrost cycles Understanding air curtains and load limits in refrigerated cases The impact of shelf configuration on proper airflow High-efficiency case designs and their practical implications Common airflow problems and troubleshooting approaches This is Part 11 in our comprehensive Rack Refrigeration Cycle series, essential knowledge for any commercial refrigeration technician. Whether you're dealing with medium-temp or low-temp cases, understanding proper airflow principles is crucial for maintaining optimal case performance and energy efficiency. #HVAC #Refrigeration #HVACTraining #CommercialRefrigeration #HVACSchool #techeducation Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this short podcast episode, Bryan and Mike from DITEK talk about what to do in tricky electrical scenarios, such as when the MCA is 27 and you have a 50A breaker. When you size an HVAC system for compatibility with voltage monitors, like the DITEK Kool Guard, you need to pay attention to the MCA (minimum circuit ampacity), which should not be confused with MOCP (maximum overcurrent protection or breaker size). As long as the MCA is 40 amps or lower, you can attach the HVAC condenser to the Kool Guard. The KG2 also accepts wire sizes up to 6 AWG. The Kool Guard is NOT a source of overcurrent protection; it is a voltage monitor rated for carrying current, which means ratings will be in MCA, not MOCP. MOCP is designed to deal with high starting amps and lets users know the maximum allowable current for a circuit so that it can trip properly when that current is exceeded. According to Section 440 of the National Electrical Code (NEC), motors with internal overload protection allow for a difference between the MCA and MOCP. You may find higher MOCPs on inverter-driven systems. Learn more about DITEK at https://www.diteksurgeprotection.com/. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

In this episode of HVAC School, I talk Solder Rings and Thermal Imaging with my My Grouchy Brother Nathan... and he whines a lot about cool tools I like. As you might have guessed, Nathan is in the camp of people who believe that proper training promotes good practices; fancy tools won't make an outstanding tech. Even though I respectfully disagree with him on some things, he has a point. Tools will only be useful if a tech knows how to use them. They should make your life easier, but they shouldn't have much bearing on performance. He doesn't like wasting money or time on tools that probably won't help him. So, he doesn't like solder rings or thermal imaging cameras. On the other hand, I'm in the "tool nerd" camp. I love new technology and think tools can make us do much better work if we learn how to use them properly. On the job and in my spare time, I enjoy reading up on the latest technology and trying out the newest tools. Missing out on the newest "wow!" tools is a fear of mine. Spending money on a tool that will help me do better, more efficient work is ALWAYS worth it. I think solder rings and thermal imaging cameras are cool and can be put to good use. We talk about how efficiency, organization, training, job performance, and customer trust relate to tools. We can find some common ground in some areas, even if we have fundamentally different attitudes toward tools. Oh, and we talk about digital gauges and the jumping spider that lives in Nathan's van. —Bryan

In Part 10 of our Rack Refrigeration Cycle series, Matthew Taylor breaks down Electronic Expansion Valves (EEVs) and their growing role in modern refrigeration systems. Learn about: How electronic expansion valves work compared to mechanical valves The importance of valve controllers and superheat calculation Common troubleshooting issues with EEVs Step counting and valve position tracking Best practices for valve initialization and maintenance Pulse Width Modulation (PWM) valves and their operation Sensor placement and maintenance tips #Key Topics Covered: EEV mechanical components and operation Controller functionality and limitations Valve synchronization methods PWM valve timing and control cycles System maintenance and common failure points 🔧 Whether you're a seasoned tech or new to the field, this video provides essential knowledge for working with modern refrigeration control systems. #HVAC #Refrigeration #TechEducation #HVACSchool #HVACR #CommercialRefrigeration #eevee Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this episode of HVAC School, we discuss the entire basic The Basic Refrigeration Circuit. We are in the business of moving heat. Heat refers to motion in the molecules. Temperature is the average velocity of those molecules. Heat needs a temperature differential to move. So, HVAC systems absorb heat when the refrigerant is colder than the ambient temperature. They reject heat when the refrigerant is hotter than the ambient temperature. Remember the components and their functions in the following order: Compressor: increases the vapor refrigerant's temperature and pressure. Discharge line: carries hot, high-pressure, superheated vapor to the condenser. Condenser: changes the vapor to a liquid. Liquid line: moves the subcooled (high-pressure) liquid to the metering device. Metering device: drops the liquid's pressure (creates some flash gas). Expansion line: leads the low-pressure liquid/vapor mixture to the evaporator. Evaporator: changes the liquid/vapor mix to a vapor. Suction line: moves superheated vapor to the compressor. Note: Heat pumps can shake things up a bit; the suction line becomes the discharge line (and vice versa), and the condenser becomes the evaporator (and vice versa). However, heat pumps have two metering devices and a bi-flow liquid line drier, so the liquid line stays the same. So, watch out for heat pump systems with that tricky little reversing valve. We also elaborate on some fancy accessories. These include accumulators, discharge line mufflers, receivers, and more. And we discuss much more...

Bryan discusses Deploying Surge Protection (SPDs) & Voltage Monitoring with Mike from DITEK, focusing on practical applications for HVAC contractors and how to provide value to clients. Mike emphasizes that surge protection is essential for modern HVAC systems, particularly given that they are typically the most expensive appliance in a home and increasingly rely on sophisticated electronic components like variable-speed compressors and inverter boards. The conversation delves into installation best practices, with a detailed discussion of proper wiring techniques for SPDs. Mike explains that surge protectors should be installed in parallel with the circuit, typically at the disconnect, and addresses common concerns about double-tapping lugs and ground connections. He emphasizes the importance of keeping wire lengths as short as possible and provides guidance for installations both with dedicated disconnects and panel-direct connections. A significant portion of the episode focuses on DITEK's Kool Guard (KG2) product, which represents an evolution in HVAC protection by combining surge protection with voltage monitoring. Mike explains how modern HVAC equipment, particularly inverter-driven systems, is increasingly sensitive to both over-voltage and under-voltage conditions. The Kool Guard monitors voltage on each phase independently and provides visual indication of fault conditions through LED indicators, making it easier for homeowners to identify potential issues without opening electrical enclosures. Key Topics Covered: · Why every modern HVAC system needs surge protection · Installation locations and proper wiring techniques for SPDs · The difference between line-side and load-side installation · Ground connection best practices · How to protect both condensers and air handlers · The evolution from basic surge protection to voltage monitoring · The importance of voltage monitoring for modern inverter-driven equipment · How Kool Guard monitors voltage phase-to-ground vs line-to-line · Common power quality issues beyond lightning strikes · How to discuss surge protection with customers · The limitations of utility-provided surge protection · The impact of aging power infrastructure on power quality · The advantages of USA-made surge protection products · How voltage monitoring prevents damage from brownouts and over-voltage conditions · The pre-programmed voltage protection ranges in Kool Guard · Visual indication features for fault conditions Learn more about DITEK at https://www.diteksurgeprotection.com/. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Join Roman Baugh as he demonstrates crucial safety protocols and post hurricane troubleshooting steps for inverter HVAC systems. In this essential guide, learn: SAFETY FIRST: Why you must check capacitor voltage (C+ & C-) even after power is disconnected How to safely verify capacitor discharge (waiting until voltage drops below 35-50V) Proper diagnosis of an L5 error code and damaged compressor plug Important tips on handling inverter systems with stored DC voltage up to 300V Step-by-step compressor winding resistance testing Complete repair process using proper crimp connectors Watch as Roman walks through a real-world repair on his own home system, showing how to safely diagnose and fix a damaged compressor plug while maintaining professional standards even in challenging post-storm conditions. #HVAC #HVACTech #HurricaneRecovery #HVACRepair #TechTips #HVACTraining #InverterSystems Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this Short #218 episode, Bryan clears up the confusion behind pumping vs. compression. Pumping is usually associated with liquid. Liquid, like vapor, is a fluid, but it's a lot denser and is essentially incompressible because the molecules are close together. Liquid volume varies based on temperature and density, but we can't squish the molecules together. That's why compressors with very little axial and radial compliance fail when flooded; they can't compress the liquid. A circulator pump in a hydronic system is an example of a pump that pushes liquid along, but the pressure difference across the pump is minimal compared to that of a compressor; the same is true of liquid vs. vapor CO2. However, vapor molecules are far apart and can be squished together to take up a smaller volume. That's why vapor can go through compressors, which take a fluid of one volume and apply pressure to shrink it to a smaller volume, raising the temperature in the process. Pneumatics, as opposed to hydraulics, utilize compression to move vapor around in a circuit. Recovery machines need to be able to compress vapor refrigerant and pump liquid into the recovery tank. Compressors and pumps can either be positive displacement or non-positive displacement systems. A positive displacement system creates a trap and forces a fixed amount of fluid through a system, like a scroll compressor or a circulator pump. Refrigerant volumes may vary because vapor density varies with temperature and pressure (the volume flow is the same, but the mass flow varies). A condensing fan motor, on the other hand, is dynamic and varies the volume of air it moves in response to pressure, as the mechanism relies on velocity and kinetic energy to move air. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Join Bryan Orr as he shares practical wisdom on pressure testing and leak detection in this training session at Polar Bear Air Conditioning. Learn valuable insights about: Why compressor terminals are surprisingly the weakest point in the system Best practices for pressure testing split systems How expansion valve operation affects pressure testing Real-world leak detection strategies using electronic detectors, bubbles, and UV dye Common mistakes to avoid when checking for leaks Tips for proper tool maintenance and calibration The pros and cons of different leak detection methods Bryan shares candid insights from years of field experience, including what actually works versus what's just theory. Perfect for both new technicians and experienced pros looking to refine their diagnostic skills. #HVAC #HVACTraining #Refrigeration #TechTips #HVACTech #HVACR #LeakDetection You can find more on Polar Bear Air Conditioning at their Youtube channel: https://youtube.com/@Polarbearky?si=0Qo_pp0BZTZQTn4N Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Trevor Matthews returns to the HVAC School Podcast to discuss Building Tech Confidence and personal growth in the HVAC and refrigeration industry w/ Refrigeration Mentor. The conversation explores the transformative power of self-investment, continuous learning, and maintaining a positive mindset. Trevor shares his personal journey from a hesitant technician to a successful business owner, highlighting the importance of pushing beyond comfort zones and embracing continuous improvement. Some fundamental mindset shifts are necessary for professional development. Trevor candidly discusses his early career struggles, including his initial fear of public speaking and technical challenges. He emphasizes that confidence isn't something that happens overnight but is built through consistent effort, studying, and maintaining a willingness to learn. The key to the growth mindset is to focus on personal progress instead of comparing your achievements to those of others, and it's a perspective that can dramatically impact professional and personal growth. Self-investment consists of dedicating time to learning, staying physically and mentally healthy, and maintaining a positive attitude, and it can open up unprecedented opportunities. Many technicians have transformed their careers by adopting a growth mindset, continuously seeking knowledge, and being willing to step outside their comfort zones. Key Topics Covered: Building professional confidence The importance of continuous learning Overcoming fear and self-doubt in technical careers Strategies for personal and professional growth Maintaining a positive mindset Investing in self-improvement Balancing work, health, and personal development The power of small, consistent actions Avoiding comparison with others Techniques for staying motivated Recommended resources for personal development Recommended Resources Mentioned: Book: "Limitless" by Jim Kwik Book: "Good to Great" by Jim Collins Book: "Think and Grow Rich" by Napoleon Hill Book: "Mastery" by Robert Greene Podcast: Hidden Brain Podcast: AC Service Tech Check out Refrigeration Mentor at https://refrigerationmentor.com/ or email Trevor at [email protected]. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Join Bryan Orr at Polar Bear Air Conditioning as he breaks down Cleaning Best Practices for cleaning Condensate Drain Lines and Pans. In this information-packed training session, Bryan covers: Different drain cleaning strategies and their pros/cons Why water flushing is often the most effective method The truth about pan tabs and chemical treatments Special challenges with aluminum coils and bacterial buildup The importance of visual inspection and proper access Prevention strategies using copper and silver Common issues in tropical climates Tips for maintaining clean drains at the equipment Bryan also discusses how proper drain maintenance ties into larger indoor air quality and equipment longevity concerns, especially in humid tropical environments. You can find more on Polar Bear Air Conditioning at their Youtube channel: https://youtube.com/@Polarbearky?si=0Qo_pp0BZTZQTn4N #HVAC #HVACTraining #DrainCleaning #HVACSchool #HVACTips #HVACR #HVACEducation #technicaltraining Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this Short #217 podcast episode, Bryan talks about the CPS Molecular Transformator and what it does. The Molecular Transformator is a version of a tube-in-shell heat exchanger, which is a method of exchanging heat from one fluid medium to another fluid medium. Tubes containing a fluid pass through a shell containing water or glycol, and there is a heat exchange between that secondary fluid and the fluid being circulated in the tubes. In a Molecular Transformator, the fluid being circulated is recovered refrigerant, and the secondary fluid is water (in a bucket), which absorbs heat from the refrigerant and cools it down to make sure that the refrigerant enters the recovery tank as a liquid. Refrigerant recovery machines have condensers inside of them, but they are quite small and don't hold a lot of refrigerant by design; many recovery machines use microchannel coils. A lot of the time, the refrigerant leaving a recovery machine is a liquid-vapor mix and too high-temperature; a lot of people run a hose over the tank or put it in a bucket of ice. The "Molecular Transformator" tries to settle the vapor molecules down into a liquid; it transforms the vapor molecules using the same mechanism as a tube-in-shell heat exchanger. The main issue is that there will be leftover refrigerant in the Molecular Transformator after recovery. However, you can mitigate this problem with ball valves and proper purging. Do so responsibly to avoid venting refrigerant. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

In Part 9 of our Rack Refrigeration Cycle series, Matthew Taylor dives deep into mechanical expansion valves - one of the most critical components in refrigeration systems. Learn about the three essential conditions required for proper metering device operation, the differences between internally and externally equalized TEVs/TXVs, and how proper valve sizing impacts system performance. Key topics covered: The three fundamental liquid conditions needed for expansion valve operation Thermal expansion valve operation and components P1, P2, P3, and P4 pressure relationships Internal vs external equalization - when to use each Proper valve sizing and correction factors Balanced vs non-balanced valve selection Q-body valve selection for supermarket applications Bulb placement considerations and best practices This in-depth training session is essential for anyone working with commercial refrigeration systems, especially supermarket rack systems. Whether you're an experienced tech or just starting out, Matt breaks down complex concepts into practical, actionable knowledge. #HVAC #Refrigeration #HVACtraining #SupermarketRefrigeration #hvaceducation Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

What are the Basics of Moving Heat? In this episode of HVAC School, Bryan talks to some apprentices about basic thermodynamics. That is the fancy scientific way of saying that we're moving heat. The way we think of "hot" and "cold" is relative to our comfort. However, the scientific concepts of "hot" and "cold" are very different from our relative understandings of those qualities. For instance, there is only ONE value of "cold" in the universe: absolute zero (0 kelvins, -460°F). Any temperature above that contains heat. Heat and temperature are NOT synonymous. Instead, heat refers to molecular motion, and temperature is an average measurement of molecular motion. Therefore, not all heat results in a temperature change. For example, adding heat to an ice cube at 32°F (0°C) changes the ice cube from a solid to liquid water. The heat added is called latent heat. Heat cannot move unless there is a differential in temperature, and it always moves from an object with more heat to one with less heat. Everything in nature tends towards equilibrium, and heat is no exception. In those cases, heat transfer will theoretically occur until both objects are at the same temperature. There are three main methods of moving heat: conduction, convection, and radiation. Conduction moves heat when a warmer object touches a cooler one. Convection occurs when heat moves through a fluid. Radiation occurs when heat moves on electromagnetic waves, such as when the sun's heat passes through a window. Join us as we cover: Heat & temperature and the difference Boiling and superheat Fahrenheit, Celsius, and Kelvin scales Absolute zero Molecular motion Hot and cold British Thermal Units (BTUs) Tons of air conditioning (and BTU/ton) Energy conversions Pressure and its effect on temperature Conduction, convection, radiation How heat transfer works in HVAC/R systems Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this enlightening episode, we sit down with Mike, a 20-year veteran from DITEK, a leading American manufacturer of surge protection devices based in Largo, Florida. The conversation begins with a brief discussion about recent hurricane impacts in the Tampa Bay area, where DITEK maintains its 65,000-square-foot manufacturing facility. Mike shares how the company, despite facing challenging weather conditions, continued its operations and maintained its commitment to American manufacturing. The bulk of the discussion centers around surge protection technology and its critical importance in protecting HVAC systems and other electronic equipment. Mike provides an excellent analogy, comparing surge protectors to pressure relief valves for electrical systems. He explains how Metal Oxide Varistors (MOVs) work as semiconductors that create low impedance paths to ground when voltage exceeds certain thresholds. The conversation delves into the evolution of MOV technology, particularly the development of thermally protected MOVs that provide enhanced safety features. The episode also addresses common misconceptions about surge protection, particularly the belief that surge protectors are primarily for lightning protection. Mike explains that while lightning strikes are a concern, especially in areas like Florida, approximately 65% of surges actually originate from within facilities themselves, often from equipment cycling on and off or other power quality issues. He emphasizes the importance of proper installation, particularly regarding ground connections and lead lengths, noting that every six inches of wire length can add about 100 volts to the clamping voltage of the device. Key Topics Covered: DITEK's history and commitment to American manufacturing Basic principles of surge protection and how MOVs work Evolution of MOV technology and thermal protection features Difference between transient voltage and temporary overvoltage (TOV) Importance of proper grounding and lead length in surge protection Cascading surge protection strategy for comprehensive protection UL testing standards and voltage protection ratings (VPR) Common misconceptions about surge protection Impact of aging v on power quality Importance of customer support and ethical business practices Installation best practices for surge protection devices Relationship between ground resistance and surge protector performance Types of surge protective devices (SPD) and their classifications Learn more about DITEK at https://www.diteksurgeprotection.com/. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

In this detailed training session, Matthew Taylor breaks down two critical components of rack refrigeration systems: sight glasses and liquid line solenoids. Learn about: Proper sight glass positioning and what different conditions tell you about your system How to interpret moisture indicators and when they need replacement The three key locations where sight glasses are commonly installed Why horizontal mounting is preferred over vertical for better diagnostics Understanding liquid line solenoid sizing (it's not based on pipe size!) How to use sizing charts and correction factors for proper solenoid selection The impact of subcooling on solenoid valve sizing and system performance Common installation mistakes and troubleshooting tips This is Part 8 in our comprehensive Rack Refrigeration Cycle series, perfect for technicians looking to enhance their commercial refrigeration knowledge. #HVAC #Refrigeration #HVACTraining #CommercialRefrigeration #HVACSchool #techtips Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this Q&A episode, Bryan Orr addresses a thoughtful question ''AM I Toxic For Caring?'' from Dan, a former military servicemember who's struggling with maintaining professional relationships while holding high standards in HVAC work. Bryan dives deep into the balance between caring about quality and working with others who may have different approaches. Key topics covered: Professional pride vs personal humility How to address quality issues without judging others The difference between workmanship standards and moral imperatives Constructive ways to influence workplace culture Finding the right work environment for your values Whether you're a perfectionist tradesperson or someone managing high-standard team members, this video offers valuable insights on maintaining excellence without creating workplace tension. Ask Bryan a question here: www.speakpipe.com/hvacschool Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this crucial installment of our Rack Refrigeration Cycle series, Matthew Taylor covers Subcooler and Liquid Pressure Regulator. Learn why mechanical subcooling is crucial for system efficiency and how it can dramatically reduce power consumption - showing how the same cooling load can be achieved with 4.5 HP instead of 15 HP! Key topics covered: How subcoolers improve system efficiency and reduce energy costs Understanding plate heat exchangers and counterflow design Proper setup and adjustment of subcooler TXVs Common troubleshooting challenges and solutions Modern electronic valve control systems vs. mechanical setups Best practices for technicians working with subcooled systems This presentation includes real-world examples and practical tips for service technicians, including why you should never adjust TXVs with the subcooler off and how to properly diagnose flooding issues. #HVAC #Refrigeration #HVACEducation #CommercialRefrigeration #HVACTrain #SubcoolingSystem Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this episode of HVAC School, Bryan talks to Leslie about the deceptive TXV. They discuss Thermostatic expansion valves, also known as TXVs or TEVs, are metering devices that maintain superheat. They contain an external equalizer. External equalizers give the pressure reading that you would normally take with a suction gauge at the end of the evaporator coil. They supply the closing force to the TXV. TXVs also contain a sensing bulb. The sensing bulb picks up the superheat on the suction line. When a vapor is superheated, its temperature exceeds its saturation temperature. The superheat value indicates how much the vapor temperature exceeds its saturation temperature. The bulb uses that superheat reading to adjust the TXV's opening force. System diagnosis can be tricky with TXVs, and you must set the charge by subcool on TXV systems. (Still check the superheat and follow manufacturer instructions, though.) However, TXV issues are pretty straightforward. Many of their issues deal with an undercharged sensing bulb. In those cases, you will notice issues with the opening force that acts on the valve. When replacing a valve, you typically make a new port for the external equalizer. However, getting solder in the tube can block off the closing force of the equalizer. Restrictions are also common issues for TXVs, and improper superheat is an indicator of a TXV restriction. When we think about the way TXVs manage superheat, "TXV" seems like a misnomer. We might be better off calling them "constant superheat valves" (CSVs). In addition, Bryan and Leslie discuss: Why a TXV instead of a TEV?.. or a CSV? Why Bryan doesn't like the name TXV Bulb, external equalizer, and spring forces Superheat and subcool Evaporator load How a TXV is supposed to work and how they fail Thanks to Daniel Anderson for making this his first episode suggestion. Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Ruchir Shah joins the podcast to share his journey into HVAC education technology and the founding of SkillCat, a comprehensive training platform for skilled trades. As a five-time entrepreneur in educational technology, Ruchir's path to HVAC was influenced by his earlier work studying the BP oil spill and developing training solutions for oil and gas workers. When COVID-19 hit and many skilled workers found themselves displaced, he recognized a broader pattern of declining income for blue-collar workers over the past 50 years, which led to the creation of SkillCat. The discussion delves into SkillCat's innovative approach to EPA 608 certification, making it more accessible and affordable at just $10 per month. Their platform uses phone-based testing with built-in security measures, achieving a 97-98% pass rate through comprehensive training. This system addresses traditional barriers like high costs, scheduling difficulties, and low pass rates that have historically made it challenging for people to enter the HVAC field. SkillCat and HVAC School have started a partnership. This collaboration aims to transform HVAC School's extensive content library into structured, accredited courses within the SkillCat platform. The partnership represents a marriage of HVAC School's technical expertise and industry insights with SkillCat's educational technology capabilities, making high-quality HVAC training more accessible and organized for both individual technicians and contracting companies. Key Topics Covered: SkillCat's origin story and mission to make trades education more accessible Revolutionary approach to EPA 608 certification testing and training Development of simulation-based training across HVAC, plumbing, and electrical trades Implementation of career pathing and progress tracking for technicians Importance of applied learning in trades education Features of SkillCat's apprenticeship program Integration of on-the-job assessments through the platform The role of educational technology in addressing the skilled trades shortage Continuous improvement approach based on user feedback Affordability and accessibility of trades education through mobile apps You can learn more about SkillCat by searching for it in the Google Play Store (Android) or App Store (iOS), or you can visit their website at https://www.skillcatapp.com/. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Join Bryan Orr as he continues his training series at Polar Bear Air Conditioning, focusing on one of the most critical yet often misunderstood aspects of HVAC installation: condensate drains and drain lines. In this detailed presentation, Bryan covers essential best practices including: Proper trap installation and common double-trapping mistakes The importance of venting and when it's needed Correct pitch requirements (1/4" per foot) Float switch installation and troubleshooting tips Best practices for drain cleaning and maintenance Special considerations for positive pressure coils Multiple unit drainage configurations Proper insulation practices for horizontal runs Bryan shares real-world examples, common pitfalls to avoid, and practical solutions gathered from years of field experience. Whether you're an apprentice or seasoned tech, this training session provides valuable insights to prevent callbacks and protect customer properties from water damage. #HVAC #HVACTraining #HVACSchool #HVACTech #Condensate #DrainLines #BestPractices #hvaceducation You can find more on Polar Bear Air Conditioning at their Youtube channel: https://youtube.com/@Polarbearky?si=0Qo_pp0BZTZQTn4N Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this short Q&A podcast, Bryan answers a listener-submitted question about apps for doing proper loads. Fred specifically asks about apps or charts that can help an HVAC contractor determine the insulation value of a home without assuming numbers or drilling into walls during load calculations. Load calculations account for all the ways that BTUs can enter or leave a home: conduction, convection, and radiation. Insulation prevents heat transfer via conduction, so it's important to the load calculation process. High-end HVAC design software like Wrightsoft and Kwik Model 3D will have these features built into them (based on the age and location of the home). ASHRAE's handbook also has tables and data with R-values and U-factors to help you out with Manual J load calculations. RED Calc is an app that allows you to calculate a wall's R-value with measurements, including surface and air temperatures indoors and outdoors. This RED Calc software is available through the U.S. Department of Energy, as is REScheck. The DOE insulation fact sheet is also quite valuable, as are The Engineering Toolbox and materials straight from the insulation manufacturers. The best way to get a comprehensive load calculation is to have a lot of tribal knowledge about how houses are built in your area, analyze energy bills, and combine tools like RED Calc with building performance tests. RED Calc is available through the U.S. DOE at https://basc.pnnl.gov/redcalc. REScheck is available at https://www.energycodes.gov/rescheck. ASHRAE's resources are available at https://ashrae.org/technical-resources. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

In this sixth installment of our Rack Refrigeration Cycle series, expert instructor Matthew Taylor dives deep into surge ambient subcoolers and dryers-filters. Learn about: The purpose and function of surge ambient subcoolers How receiver bypass works and when it's used The importance of proper filter installation and maintenance Different types of filter-driers and their specific applications Best practices for checking and changing dryers Matthew breaks down complex concepts into easy-to-understand explanations, providing valuable insights for both newcomers and experienced technicians. Whether you're troubleshooting issues or looking to optimize system performance, this video is packed with practical knowledge you can apply on the job. #HVACSchool #RackRefrigeration #Subcoolers #Filters #hvactraining101 Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Bryan sits down with Jim Bergmann at the NCI Summit in Asheville, North Carolina, to discuss the latest developments in HVAC technology, training, and industry trends. The discussion delves into the evolution of MeasureQuick 3.0, highlighting the shift back to a more technician-centric approach. Jim explains how they've redesigned the software to put gauges front and center and implemented an AI-driven system to guide technicians through the process step-by-step. This renewed focus on the end-user experience aims to make the product more valuable for technicians and, in turn, more likely to be adopted as part of standard operating procedures in HVAC companies. Jim and Bryan also explore the importance of understanding HVAC history and fundamentals. They discuss how revisiting old engineering books can provide valuable insights into the core principles of the industry, often explained in more accessible terms than modern textbooks. This approach to learning, combining practical experience with theoretical knowledge, is something both Jim and Bryan advocate for in technician training and development. The conversation then shifts to the challenges and opportunities in the HVAC industry, particularly in light of the push for electrification and the adoption of heat pump technology. Jim emphasizes the critical need for proper evacuation techniques and moisture removal in systems, especially for cold-climate heat pumps. He stresses the importance of standardized processes and documentation to ensure consistent quality in installations and maintenance. Topics covered in the podcast: MeasureQuick 3.0 updates and user interface improvements The importance of technician-centric product design Partnerships between MeasureQuick and organizations like NCI The value of understanding HVAC history and fundamentals Challenges and opportunities in adopting heat pump technology The critical importance of proper system evacuation techniques Standardizing processes for HVAC technicians in the field The role of technology in attracting younger workers to the HVAC industry The benefits of attending industry events like the NCI Summit The ongoing need for collaboration and knowledge sharing in the HVAC community Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Join Bryan Orr from HVAC School as he delivers an in-depth presentation on Installation Best Practices, focusing on Brazing and Leak Checking techniques. This video is Part 1 of a special series recorded at Polar Bear Air Conditioning. In this episode, Bryan covers: The importance of proper brazing techniques Understanding the science behind brazing Tips for achieving stronger joints Common mistakes to avoid The significance of flowing nitrogen while brazing Choosing the right brazing rod for different applications Techniques for working with various metals, including aluminum Whether you're a seasoned HVAC professional or just starting in the field, this video offers valuable insights to enhance your installation skills and troubleshooting abilities. Stay tuned for more parts in this comprehensive series on HVAC best practices! You can find more on Polar Bear Air Conditioning at their Youtube channel: https://youtube.com/@Polarbearky?si=0Qo_pp0BZTZQTn4N #HVACSchool #BryanOrr #Brazing #LeakChecking #HVACTips Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this short podcast episode, Bryan answers a listener-submitted question about an HVAC system that won't dehumidify. This question was submitted by a homeowner with a Carrier heat pump with an attic air handler that cools but won't dehumidify on the hottest days of summer. One of the past companies that serviced the system added charge, but the problem wasn't resolved. This case doesn't seem to be a sizing issue, as the insufficient dehumidification is happening on the hottest days. Normally, sizing issues happen during the edge seasons when temperatures aren't as high as in the summer, but the dew points are still high. Bryan's first recommendation is to use measureQuick to evaluate the delivered capacity and determine the sensible heat ratio (SHR) by comparing sensible BTUs to latent BTUs. High SHRs are associated with less effective dehumidification and more effective sensible BTU removal. Then, we have to determine that airflow is properly dialed in. Typically, lower fan speeds are associated with better dehumidification; 350 CFM per ton is typical of humid climates. In the case of two-speed or variable-speed equipment, we should verify that it is staging up and down properly. On the ventilation side, a duct leakage test is recommended. Proper use of exhaust ventilation, like bath fans and kitchen exhaust, is also critical. Structural leakage and MAD-AIR are also worth checking if a company can measure those, though those are premium services that are usually more expensive. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Join Matthew Taylor in this comprehensive breakdown of liquid receivers in rack refrigeration systems. As part 5 of our Rack Refrigeration Cycle series, this video delves deep into the crucial components and functions of liquid receivers. Key topics covered: Horizontal and vertical receiver designs Float alarms and liquid level monitoring Pressure relief valves and safety mechanisms Receiver tank alarm (RTA) systems Wiring diagrams and electrical components Matthew shares invaluable insights on: Proper refrigerant charging levels Troubleshooting techniques Safety considerations and best practices Whether you're an HVAC professional or a student, this video provides essential knowledge for understanding and maintaining rack refrigeration systems. Don't miss this opportunity to enhance your expertise in commercial refrigeration! Check out the rest of our Rack Refrigeration Cycle series for a complete understanding of these complex systems. #HVACSchool #RackRefrigeration #Refrigeration #HVACTraining #commercialhvac Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this Part 4 of our Rack Refrigeration Cycle series, expert Matthew Taylor dives deep into low ambient cooling strategies for supermarket refrigeration systems. Learn about: The importance of maintaining proper discharge pressure How split condensers work and why they're crucial The role of holdback valves in flooding condensers Proper setup and adjustment of holdback (A8) and receiver (A9) valves Common issues caused by incorrect valve settings Strategies for dealing with extremely low ambient temperatures Whether you're a seasoned HVAC technician or just starting out, this video provides valuable insights into managing refrigeration systems during cold weather. Don't miss this essential addition to your refrigeration knowledge! #HVACSchool #Refrigeration #LowAmbientCooling #SupermarketHVAC Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Shh... It's time for some hilarious HVAC ASMR bloopers w/ our favorite tech, Bert! Ever wondered what happens behind the scenes when we try to make those soothing ASMR repair videos? Well, wonder no more! In this blooper reel, watch Bert and the team fumble through whispered instructions, struggle with stubborn screwdrivers, and attempt to make satisfying sounds... with varying degrees of success. Highlights include: Bert's whisper-yelling adventures The great compressor conundrum A lesson in how NOT to use a funnel The mysterious case of the disappearing button Whether you're an HVAC pro looking for a laugh or just love seeing the human side of your favorite Kalos techs, this video is guaranteed to bring a smile to your face. Don't forget to turn up the volume to catch all the whispered chaos! Remember to like, comment, and subscribe for more HVAC content - both serious and silly - from your friends at Kalos Services. #HVACASMR #Bloopers #KalosServices #HVAC #FunnyMomentsASMR Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this Part 3 of our Rack Refrigeration Cycle series, Matthew Taylor dives deep into the complex world of oil systems in commercial refrigeration. This informative presentation covers: The importance of oil separators and their efficiency Low-pressure oil systems and their components Understanding oil reservoir levels and pressure differentials Troubleshooting common oil-related issues The impact of refrigerant changes on oil circulation Interpreting sight glass readings and oil line temperatures Whether you're a seasoned HVAC technician or just starting in the field, this video provides valuable insights into maintaining and diagnosing oil systems in rack refrigeration units. Join Matthew as he breaks down these crucial concepts with real-world examples and expert tips. Don't miss the other videos in our Rack Refrigeration Cycle series for a comprehensive understanding of commercial refrigeration systems. #HVACSchool #RackRefrigeration #OilSystems #hvactraining101 Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

This episode of the HVAC School podcast dives deep into the often-overlooked but critical topic of water issues in HVAC systems. Bryan and Bert discuss the various causes of water leaks and condensation problems, and they explain how to prevent them. They emphasize that water damage is not an inevitable part of HVAC systems and that with proper attention to detail and understanding of the underlying causes, most issues can be prevented. "Spidey Sense" refers to a heightened situational awareness that allows technicians to anticipate and prevent water-related problems. Common water-related problems include drain backups, improper trap depth, and freezing issues, and Bryan and Bert provide practical advice on how to identify and address these problems. The conversation also covers the importance of proper installation techniques, including the correct placement of float switches, insulation of copper lines, and the pitching of secondary drain pans. Bryan and Bert highlight the need for technicians to think critically about the root causes of water issues rather than relying on quick fixes or common misconceptions. They debunk myths such as thermostats being set too low and causing freezing, and they emphasize the importance of addressing underlying airflow problems. They also discuss the challenges of condensation in humid climates and the importance of setting proper customer expectations. Key topics covered in the podcast include: Common causes of water leaks in HVAC systems The importance of proper drain installation and maintenance Freezing issues and their real causes Secondary drain pan installation and common mistakes The role of static pressure in drainage problems Condensation issues on outdoor units and in humid climates The importance of proper insulation for copper lines and drains Best practices for installing and connecting float switches Debunking myths about thermostat settings causing freezing The need for critical thinking and thorough investigation of water issues Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Join us for an insightful presentation on "The Fundamentals of CO2 Refrigeration" by Trevor Matthews, recorded during the 5th Annual HVAC/R Training Symposium. Trevor, an experienced refrigeration professional and founder of Refrigeration Mentor, breaks down the basics of CO2 refrigeration systems, demystifying this increasingly popular natural refrigerant technology. In this comprehensive overview, you'll learn: The fundamentals of refrigeration cycles and how CO2 systems compare Key terminology and concepts specific to CO2 refrigeration The differences between subcritical and transcritical CO2 systems Safety considerations and best practices for working with CO2 Advantages and challenges of CO2 systems compared to synthetic refrigerants Future trends in CO2 technology for both commercial and residential applications Whether you're an HVAC/R technician looking to expand your skills or a contractor curious about emerging technologies, this presentation offers valuable insights into the world of CO2 refrigeration. Don't miss this opportunity to learn from one of the industry's leading educators! #HVACSchool #CO2Refrigeration #HVACRTraining #naturalrefrigerants Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this short Q&A podcast episode, Bryan answers a listener-submitted question about cultural diversity in the workplace, especially at an HVAC company. He addresses how we can deal with cultural and language differences in a field where communication is so important. Being open to different demographics of people is great for the industry, especially since we have an aging workforce and need good people in the trade. There are also plenty of opportunities in the trade. However, that doesn't automatically erase the challenges associated with hiring people who don't speak English fluently with English-speaking clients, especially when it comes to money conversations. (However, you can also increase your client base by being able to serve people who speak other languages.) Our operations can aid these people and help them integrate into the workplace by offering ESL classes as a workplace benefit, encouraging everyone to be clear and concise in their communication, embracing other forms of communication (like sharing photos), and offering scripts or guidelines for communicating with customers. Cultures vary, and we can't afford to take a mindlessly xenophobic or excessively open approach. We need to acknowledge what's good for the business and uphold standards, but we need to make space for people of different backgrounds to succeed and contribute to the company and industry. It's also great to get to know people who aren't like us and show interest in other cultures, especially when we get to know them and their families. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Join Matthew Taylor in this informative presentation on the rack refrigeration cycle. In Part 2 of our series, Matthew dives deep into compression and oil management systems in supermarket refrigeration. Key topics covered: Types of compressors used in supermarket refrigeration Oil management systems and their importance Mechanical and electronic oil controls Safety switches and their functions High pressure, low pressure, and oil safety controls Proper adjustment and testing of safety switches Overload protection and control circuitry Whether you're an HVAC technician, student, or industry professional, this video provides valuable insights into the complexities of rack refrigeration systems. Matthew shares practical tips, common issues, and best practices for maintaining and troubleshooting these critical components. #HVACSchool #RackRefrigeration #Compressors #OilManagement #hvactechnician Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join HVAC expert Matthew Taylor as he kicks off an in-depth series on the parallel rack refrigeration cycle. In Part 1, Matthew breaks down the fundamentals of rack refrigeration systems, covering: What a refrigeration rack is and why it's used Different types of racks and their components How to read and interpret rack engineering data The importance of understanding refrigerant properties, including glide and midpoint Critical factors in setting up and troubleshooting rack systems Whether you're new to commercial refrigeration or a seasoned tech looking to sharpen your skills, this video provides essential knowledge for anyone working with supermarket cooling systems. Matthew's practical approach and real-world examples make complex concepts easy to grasp. Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this informative Q&A with Bryan Orr, tackles a viewer's question about How to Deploy a Dehum in sealed homes. Bryan covers key topics including: Proper placement of dehumidifiers in sealed attics and homes Importance of addressing HVAC equipment issues before adding dehumidifiers Considerations for ventilation and outdoor air integration Strategies for attic dehumidification vs. whole-house solutions Factors to consider when choosing a dehumidification approach Whether you're an HVAC professional or a homeowner dealing with humidity issues, this video provides valuable insights into effective dehumidifier deployment. Bryan shares best practices, discusses regional considerations, and offers expert advice to help you make informed decisions about moisture control in residential settings. #HVAC #Dehumidification #MoistureControl #hvactips Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join us for an engaging and insightful presentation by Ty Branaman on "Teaching the Invisible" from the 5th Annual HVAC/R Training Symposium. In this video, Ty demonstrates innovative ways to make abstract HVAC concepts tangible and exciting for learners. Highlights include: Visualizing air movement and pressure differentials Understanding heat transfer and evaporation Demonstrating refrigeration principles with everyday objects Creative approaches to explaining combustion and gas laws Whether you're an HVAC instructor, technician, or enthusiast, Ty's presentation offers fresh perspectives on how to make complex ideas accessible and fun. Discover new tools and techniques to enhance your understanding and teaching of HVAC fundamentals. #HVACTraining #TeachingTechniques #HVACEducation #RefrigerationPrinciples Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this episode of the Spidey Sense series, Bryan and Bert dive deep into the art of refrigerant leak detection, sharing their wealth of experience and practical tips for HVAC technicians. They emphasize the importance of using one's senses and observation skills before relying solely on electronic tools, highlighting how this "Spidey Sense" approach is a hallmark of senior-level expertise in the field. Visual and tactile cues, including warm suction lines, frosted components, and signs of oil, are vital. Different symptoms point to specific kinds of leaks and various scenarios, so you need to understand the behavior of the system. Bryan and Bert also discuss the strategic application of soap bubbles, electronic leak detectors, and nitrogen for pressurization. Each method has limitations, and you'll need to know when to employ them for maximum effectiveness. When detecting leaks, consider recent home renovations or equipment vibrations that might contribute to leaks. Topics covered in the podcast include: Visual and tactile cues for identifying potential refrigerant leaks The debate on frosted lines as indicators of low refrigerant charge Proper use of electronic leak detectors and their limitations Strategic application of soap bubbles in leak detection The importance of checking common leak locations (e.g., flare fittings, evaporator coils) Considerations for leak detection in newly installed or recently serviced systems The role of nitrogen in leak detection for systems with very low refrigerant charge Estimating the severity of a leak based on system pressure and charge level The pros and cons of isolation tests for line set leaks Techniques for detecting very small, slow leaks that might not show up in pressure tests The potential use of ultrasonic leak detection tools The importance of thorough inspection and patience in the leak detection process Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Experience the soothing world of HVAC maintenance with our latest ASMR video featuring Bert! In this unique and relaxing experience, watch and listen as Bert expertly performs a refrigerant leak repair. Highlights: Witness the smooth and satisfying process of leak detection Enjoy the calming sounds of pressure release and system purging Learn about proper refrigerant handling techniques Observe the meticulous steps of an HVAC professional at work Whether you're an HVAC technician looking to unwind or just curious about leak detection and repair, this video offers a perfect blend of education and relaxation. Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this short Q&A podcast episode, Bryan answers Edward's question about how to deal with customers who ask, "Why didn't you notice it last time?" There isn't an easy answer to that question. The truth is that air conditioning and home health and comfort issues are complicated, and it's entirely possible that an issue simply went unnoticed (or the symptoms simply weren't apparent yet). The HVAC industry doesn't have a standard slate of tests that can give a comprehensive view of everything that's wrong with a system all at once. It's similar to how a doctor can offer a second opinion that differs from the first doctor you saw. You have to determine whether the customer wants to place blame or solve the problem when they ask, "Why didn't you notice it last time?" Sometimes, we need to dig deeper to find the root of the problem. We can offer advanced diagnostics and be honest about what that will entail (including pricing), though it's natural for customers to be apprehensive about being sold options. However, we don't want to avoid pursuing solutions either. There are ways to talk about previous sloppy or incomplete work without placing blame on another technician. The immediate problem is what requires attention, not the last person who worked on the system. Ask the customer to state their goals and the results they want to see, and you can forge a path ahead. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Join us for an inspiring presentation from the 5th Annual HVAC/R Training Symposium! Trevor Matthews, founder of Refrigeration Mentor, shares powerful insights on personal development and mindset strategies specifically tailored for HVAC/R professionals. In this talk, Trevor covers: Setting yourself up for success with smart goal-setting Breaking old habits and developing new ones Creating an actionable plan for your career Building confidence in your journey Overcoming limitations and embracing setbacks as learning opportunities Whether you're a seasoned tech or just starting in the field, Trevor's practical advice and motivational approach will help you take your career to the next level. Learn how to create the blueprint for the life you want, both personally and professionally. Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this episode of the HVAC School podcast, host Bryan dives deep into the topic of vacuum in HVAC and refrigeration systems. He addresses two questions from social media about vacuum, expanding them into a comprehensive discussion of best practices, common issues, and techniques for effective vacuum procedures. Bryan starts by explaining where to ideally locate a vacuum pump when working on a refrigeration system. He emphasizes the importance of pulling from the largest volume locations possible, often at multi-position service valves on the compressor or wherever accessible ports are available. He notes that systems that have been in operation pose unique challenges due to refrigerant dissolved in the oil, which can significantly increase vacuum time. The podcast then covers the "one hose method" for pulling vacuum, detailing the process of using a single large hose connected to the suction side with the core removed, while placing the micron gauge on the liquid side. Bryan explains how this method can be highly effective for new systems but may take longer for systems that have been in operation. He also discusses the importance of valve quality. Key topics covered in the podcast include: Ideal vacuum pump location in refrigeration systems The "one hose method" for pulling vacuum Challenges of vacuuming systems that have been in operation Using heat and nitrogen to improve vacuum efficiency Importance of quality valves and tools in vacuum procedures Proper maintenance of vacuum pumps and micron gauges Dealing with refrigerant dissolved in oil during vacuum The science behind evaporation at the oil-vapor interface Tips for speeding up vacuum in difficult conditions Recommended resources for further learning about vacuum techniques Get your copy of Review of Vacuum for Service Engineers at TruTech Tools HERE. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Who Actually Invented A/C and Why? Join Bryan Orr as he dives into the fascinating origins of air conditioning. Discover the surprising truth behind who really invented A/C and the motivations that led to this game-changing technology. In this video, Bryan explores: The common misconception about Willis Carrier The often-overlooked contribution of Dr. John Gorrie How yellow fever and malaria influenced A/C development The connection between ice-making and modern refrigeration Florida's unique relationship with air conditioning Whether you're an HVAC professional, history buff, or just curious about the cool air you enjoy, this video offers an engaging look at the inventors who changed how we live and work. Learn how A/C went from treating paper to treating people, and why Florida owes so much to this invention. #ACHistory #HVAC #FloridaHistory #KalosServices Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this episode Q&A - Drain Traps & Static - Short #209, Bryan answers a question about drain traps and static pressure. This question was sent by Stephen with The Comfort Squad when he noticed an uptick in nuisance calls on retrofit systems that kept having their secondary drain pans filled. In negatively pressurized systems (i.e., straight-cool or heat pump units, not gas furnaces), air can pull water back into the drain line. The evaporator coil is under negative pressure because the blower is on top of the evaporator coil. The rule of thumb for trap depth is that it should be greater than or equal to twice the return static pressure (which is why a 1" deep trap is typical for systems with 0.5" return static pressure). However, return static can have some variation, and it's also not a great idea to use the TESP for this measurement because the return static could be greater than the supply. It makes most sense to account for the highest possible return static you will see. 1" is only sufficient if 0.5" return static pressure is the most you will see, so bigger is usually better in all cases. If you can install a 2" or 3" trap, you'll typically have your bases covered without having an excessive trap. We also wrote a tech tip about this topic: https://hvacrschool.com/drain-trap-depth-and-negative-pressure/ Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

In this Q&A with Bryan Orr on Drain Traps & Static, we address a common HVAC issue: condensate trap depth and its relationship to static pressure. Learn why your standard 1-inch trap might not be enough for high-static systems, and discover the rule of thumb for determining the right trap depth. We'll explain: How negative pressure affects condensate traps The connection between static pressure and trap depth When and why to consider deeper traps Tips for proper trap sizing in residential systems Perfect for HVAC technicians dealing with nuisance calls and overflow issues. Stay tuned for more practical HVAC knowledge! Condensate Drains Install & Service: https://www.youtube.com/watch?v=P9lnMLdE-r0&t=148s #HVAC #CondensateTraps #StaticPressure #hvactips Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Tyler Nelson, Instrumentation & Industrial Sales Manager at Sauermann Americas, for an in-depth presentation on Combustion Analysis and Troubleshooting from the 5th Annual HVAC/R Training Symposium. In this informative session, Tyler covers: The importance of combustion analysis in modern HVAC systems Types of combustion and how to achieve optimal performance Seven key functions of effective combustion analyzers Best practices for testing and commissioning new equipment How to use analyzers for diagnostics and preventive maintenance Carbon monoxide safety and the risks technicians face The impact of new regulations and industry changes on combustion testing Whether you're a seasoned pro or new to the field, this presentation offers valuable insights to enhance your combustion analysis skills and troubleshooting abilities. Learn how to ensure safety, efficiency, and longevity in the systems you work with. Don't miss this opportunity to learn from an industry expert and take your HVAC knowledge to the next level! #HVAC #CombustionAnalysis #HVACTraining #techniciantips Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this Q&A video, we tackle a common HVAC issue: condensation forming around supply registers and vents. Join us as we dive deep into the causes of this pesky problem and explore effective solutions. Key points covered: Why moisture forms around supply vents and registers The role of attic conditions in vent condensation Common misconceptions about "hot meeting cold" How to properly address condensation issues in attics and living spaces The importance of controlling indoor humidity levels Why simply adding more insulation isn't always the answer Practical tips for sealing and managing moisture in your HVAC system Whether you're a homeowner dealing with sweaty vents or an HVAC professional looking to expand your knowledge, this video provides valuable insights and actionable advice. Don't miss out on these expert tips to keep your home dry and comfortable! Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

This is a presentation ''The Great Heat Pump Revolt of 2026 and How To Avoid It'' from the 5th Annual HVAC/R Training Symposium. Industry experts Steve Rogers, Russ King, and Chris Hughes dive deep into the challenges and pitfalls that HVAC contractors may face as heat pumps become more prevalent across the United States. With the push for electrification and generous government incentives driving the rapid adoption of heat pumps, the presenters walk through critical considerations when installing heat pumps in different climate zones. They cover topics such as: Proper load calculations and sizing for heat pumps vs traditional HVAC systems Ensuring duct systems can handle the airflow requirements of heat pumps Addressing issues like short-cycling, stratification, and outdoor duct leakage Optimizing control strategies to balance heat pump and supplemental heating performance The presenters draw on their decades of real-world experience to provide actionable advice HVAC professionals can use to successfully navigate the coming "heat pump revolt" and keep their customers satisfied. Whether you're new to heat pumps or a seasoned veteran, this presentation is a must-watch to prepare for the changing HVAC landscape. Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this informative Q&A session, Bryan Orr answers Stephen's question about testing dehumidifiers. Learn the key metrics to measure, including dew point delta, grains of moisture, and condensate production. Bryan breaks down: The basics of dehumidifier operation Essential measurements for performance testing Using psychrometric charts and apps The importance of manufacturer specifications Factors affecting dehumidifier efficiency Whether you're an HVAC professional or a curious homeowner, this video provides valuable insights into dehumidifier testing and troubleshooting. Bryan also shares his recommended tools and resources for accurate measurements. Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this episode, Bryan and Max discuss commercial supermarket startup and commissioning with comparisons to residential HVAC work. Max, who has transitioned from residential air conditioning to supermarket refrigeration, shares his insights on the unique challenges and requirements of this specialized field. The conversation begins by emphasizing the critical importance of safety in supermarket refrigeration work. Unlike residential jobs, technicians often work alone in potentially hazardous environments with high-voltage equipment and large quantities of refrigerant. Hearing protection is stressed as a crucial safety measure due to the extremely loud environments in motor rooms. Max then delves into the complexities of supermarket refrigeration systems, describing the various components involved, including parallel compressor racks, refrigerated cases, and multiple control systems. He highlights the need for adaptability and problem-solving skills, as technicians often encounter unique situations with limited documentation or manufacturer support. The discussion also covers the time-sensitive nature of the work, with many tasks needing to be completed overnight to minimize disruption to store operations. The podcast explores the multifaceted role of a supermarket refrigeration technician, touching on topics such as equipment decommissioning, pressure testing, electrical verification, and programming of control systems. Max emphasizes the importance of developing a comprehensive process and continuously refining it to improve efficiency and effectiveness in the field. Key topics covered in the podcast: Safety considerations in supermarket refrigeration work Components of commercial refrigeration systems (compressor racks, cases, controls) Time constraints and overnight work in supermarket settings Decommissioning old equipment and installing new systems Pressure testing and leak checking procedures Electrical verification and three-phase power considerations Programming and verifying control systems Defrost cycle setup and verification Communication protocols and building management systems Performance audits and client expectations Low ambient controls and regional differences in system requirements Leak detection and walk-in cooler maintenance The importance of developing and refining work processes Transition from residential HVAC to commercial refrigeration Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

In this video, Bryan Orr introduces the game-changing 50M56X-843 universal integrated circuit board from White-Rodgers and Copeland. Learn how this versatile replacement part works with both PSC and ECM X (X13) motors, and comes complete with a hot surface igniter. Key features: Compatible with most PSC and ECM X motor furnaces Built-in flame rod current measurement No additional harnesses or wires needed Easy configuration using White-Rodgers Connect app and NFC technology Watch as Bryan demonstrates the simple setup process using the WR Connect app, showcasing how you can quickly configure the board to match OEM specifications or make custom adjustments. Whether you're a seasoned HVAC pro or just starting out, this video will show you why the 50M56X-843 is a must-have for your toolkit. https://copeland.pathfactory.com/white-rodgers/50m56x-843?utm_source=partner&utm_medium=influencer&utm_campaign=7016Q0000021QdxQAE_Heating_WRConnect-50M56X-843&utm_term=bryanorr&utm_content=50m56x843infpromosept24&lead_source=partner&lead_channel=influencer #HVAC #Copeland #WhiteRodgers #FurnaceRepair #hvactech Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this episode, Matthew Taylor joins the podcast to dive deep into the world of pressure-limiting valves and regulators used in refrigeration and air conditioning systems. They explore the intricacies of Maximum Operating Pressure (MOP) expansion valves, Evaporator Pressure Regulators (EPR), and Crankcase Pressure Regulators (CPR), discussing their functions, applications, and differences. The conversation begins with an explanation of MOP expansion valves, which are commonly used in low-temperature refrigeration applications and air conditioning systems. Matthew describes how these valves work by using a vapor-charged thermal element to limit the suction pressure, protecting compressors from operating outside their designed range. They discuss the differences between liquid-filled, vapor-charged, and cross-charged valves, highlighting how each type affects system performance and superheat control. The discussion then shifts to larger systems and rack refrigeration, where Crankcase Pressure Regulators (CPRs) are preferred over MOP valves. Matthew explains how CPRs control pressure closer to the compressor, allowing for better superheat control in systems with longer piping runs. The conversation concludes with an explanation of Evaporator Pressure Regulators (EPRs), which are used in multi-evaporator systems to maintain specific evaporator temperatures independently of the overall system suction pressure. Topics covered in the podcast: · Maximum Operating Pressure (MOP) expansion valves · Liquid-filled vs. vapor-charged thermal elements · Cross-charged valves and superheat control · Applications of MOP valves in small refrigeration systems and air conditioning · Crankcase Pressure Regulators (CPRs) for larger systems · Evaporator Pressure Regulators (EPRs) for multi-evaporator setups · Differences between MOP, CPR, and EPR in pressure control · Challenges of pressure control in rack refrigeration systems · Impact of pressure-limiting devices on compressor longevity · Considerations for technicians when working with different types of systems Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Join Ed Janowiak as he delivers an insightful presentation on "A Walk Through the Residential Design Series (ACCA Manuals J, S, D)" at the 5th Annual HVAC/R Training Symposium. In this informative session, Ed breaks down the essential components of proper HVAC system design using the ACCA manuals. Key topics covered: Overview of Manual J (load calculations) Understanding Manual S (equipment selection) Exploring Manual D (ductwork design) Common misconceptions and mistakes Tips for achieving predictable results Ed's engaging presentation style and wealth of experience make complex concepts easy to understand. Whether you're new to HVAC design or looking to refresh your knowledge, this video offers valuable insights into creating efficient and effective residential HVAC systems. #HVACSchool #ACCAManuals #HVACDesign #ResidentialHVAC Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Ever wondered what refrigerants really are and how they've evolved? In this video, we dive into the fascinating history and science of refrigerants, from early evaporative cooling to today's advanced A2L refrigerants. We cover: The basics of evaporative cooling Benjamin Franklin's experiments with ether and alcohol The birth of closed-loop systems Early refrigerants like ammonia and methyl chloride The game-changing introduction of Freon (R12) Environmental concerns and the phaseout of CFCs and HCFCs The rise and fall of R410A Modern A2L refrigerants and their properties The ongoing use of CO2 and ammonia in specialized applications Learn why we're moving towards mildly flammable refrigerants and the trade-offs of this move. Whether you're an HVAC pro or just curious about how your AC works, this video breaks down the history and science of refrigerants in a way everyone can understand. Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Trevor Matthews from Refrigeration Mentor as he delivers an insightful presentation on "How To Properly Inspect a Failed Compressor" at the 5th Annual HVAC/R Training Symposium. In this comprehensive session, Trevor walks through the step-by-step process of troubleshooting and inspecting semi-hermetic compressors. Key topics covered: Safety precautions when working with compressors Understanding compressor components and their functions Proper electrical testing procedures Importance of checking oil levels and quality Identifying common failure patterns Hands-on demonstration of compressor teardown Whether you're a seasoned technician or new to the field, this video provides valuable insights to enhance your compressor diagnostic skills. Learn how to avoid common mistakes, properly identify the root cause of failures, and make informed decisions about compressor repair or replacement. A Compressor Story w/ Trevor Matthews: www.youtube.com/watch?v=OvAdDRclyb0&t=12s #HVAC #Compressors #HVACTraining #Refrigeration #TechnicianTips Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

HVAC expert Bert demonstrates how to use a flow hood to properly balance an HVAC system. Watch as he measures and adjusts airflow throughout the house, focusing on the newly installed ductwork and manual dampers. Key points covered: Measuring CFM (cubic feet per minute) at each vent Adjusting manual dampers to balance airflow Tips for handling oversized systems Balancing techniques for different room types This video provides valuable insights for HVAC professionals and homeowners alike, showcasing the importance of proper system balancing for optimal comfort and efficiency. #HVAC #AirflowBalancing #FlowHood #HVACTips Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join HVAC experts Sam Myers and Eric Kaiser as they present "A Duct Up Situation" at the 5th Annual HVAC/R Training Symposium. In this informative session, Sam and Eric dive deep into the world of ductwork, sharing their wealth of knowledge and practical experience. Learn about: Common ductwork issues and how to address them Best practices for duct design and installation Improving system efficiency through proper duct sizing Troubleshooting techniques for duct-related problems Whether you're a seasoned HVAC professional or just starting in the field, this presentation offers valuable insights to enhance your understanding of ductwork and its critical role in HVAC systems. #HVAC #Ductwork #HVACTraining #hvacrepair Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this video Bert demonstrates how to use MeasureQuick to commission a newly installed HVAC system. Watch as he walks through the step-by-step process of: Setting up a new project in MeasureQuick Entering system details and equipment information Using the TrueFlow Grid to measure airflow accurately Taking static pressure measurements Capturing refrigerant pressures and temperatures Recording electrical measurements Learn how to utilize this powerful tool to ensure your installations are operating at peak performance. Bert shows you how to generate a comprehensive report that can be shared with customers, proving the quality of your work. #HVAC #MeasureQuick #Commissioning #HVACSchool Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bryan Orr in this eye-opening 3D animated journey through the world of Indoor Air Quality (IAQ). Whether you're an HVAC professional or a homeowner, understanding IAQ is crucial for maintaining a healthy living environment. In this video, we explore: The main indoor air pollutants and their sources Health impacts of poor IAQ Essential components of IAQ management Effective strategies for improving indoor air quality DIY solutions and affordable IAQ monitors Watch as Bryan breaks down complex concepts into easy-to-understand visuals, covering everything from particulate matter and VOCs to humidity control and ventilation systems. Learn about the latest EPA recommendations and discover practical tips for enhancing your home's air quality. Don't miss our 3D animations of: Particulate matter sizes and their effects How different MERV filters work The Comparetto Cube DIY air filter Proper ventilation techniques Whether you're looking to upgrade your HVAC skills or simply want to breathe easier at home, this video is your comprehensive guide to IAQ basics. #IndoorAirQuality #HVAC #HomeImprovement #healthyliving Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join industry experts Don Gillis and Christian Pyles as they dive deep into the world of A2L refrigerants during the 5th Annual HVAC/R Training Symposium. This informative presentation covers everything you need to know about the upcoming transition to A2L refrigerants in the HVAC industry. Key topics covered: The global shift towards lower GWP refrigerants Differences between A1 and A2L refrigerants Safety considerations and flammability characteristics New equipment designs and mitigation strategies Installation and service best practices Updates on codes and standards Whether you're a seasoned HVAC professional or just starting in the field, this presentation provides valuable insights into the future of refrigerants and how it will impact your work. Don and Christian break down complex topics into easy-to-understand information, helping you prepare for the changes ahead. Inch Calculator: https://www.inchcalculator.com/refrigerant-line-charge-calculator/ #HVAC #A2LRefrigerants #HVACTraining #RefrigerantTransition #HVACSchool Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

The Kalos team faces on their TALLEST tasks yet-upgrading the HVAC at former Orlando Magic star Bo Outlaw's Florida home Bert demonstrates installing a buck-boost transformer to protect sensitive HVAC equipment. Learn why these transformers are crucial for areas with unstable power and how they can prevent damage to inverter boards. Key points covered: Why buck-boost transformers are necessary How they protect against sustained high voltage Step-by-step installation process Testing voltage before and after installation Whether you're an HVAC professional or a curious homeowner, this video provides valuable insights into improving the longevity and performance of your HVAC system. Don't miss this essential guide to safeguarding your equipment against power fluctuations! #HVAC #BuckBoostTransformer #HomeUpgrades #HVACSchool Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join industry veteran Rob Minnick as he shares his journey from traditional HVAC to a holistic home performance approach. In this enlightening presentation from the 5th Annual HVAC/R Training Symposium, Rob explains why HVAC contractors need to consider the whole house when addressing comfort issues. Key topics covered: Rob's background in HVAC and his eye-opening experience with home performance The limitations of focusing solely on HVAC systems How air leakage affects comfort and energy efficiency The importance of continuous learning in the HVAC industry Why blower door testing is crucial for diagnosing home comfort problems Whether you're an HVAC professional looking to expand your skills or a homeowner interested in understanding whole-house comfort, this presentation offers valuable insights into the intersection of HVAC and home performance. #HVAC #HomePerformance #HVACTraining #energyefficiency Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Elliot from HVAC School as he walks you through essential duct Duct Prep Tips a Tricks for flawless installations. In this video, you'll learn: How to properly clean duct collars for optimal connections The importance of stretching ductwork before installation Techniques for cutting precise holes in plenum boxes Proper methods for attaching collars and sealing connections Tips for installing manual dampers for airflow balancing Whether you're a seasoned pro or just starting out, these tried-and-true methods will help you achieve better, more efficient duct installations. Don't miss this opportunity to elevate your HVAC skills! Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Luke Peterson, owner of Magnolia Home Comfort in Louisville, KY, as he shares invaluable insights on becoming a more thorough HVAC technician. In this enlightening presentation from our 5th Annual HVAC/R Training Symposium, Luke explores: The importance of thoroughness in HVAC work Common hindrances to being thorough How to cultivate the right mindset for excellence Practical tips for improving efficiency and reducing callbacks The impact of thoroughness on customer satisfaction and career fulfillment Whether you're a seasoned pro or just starting in the field, Luke's experience and practical advice will help you elevate your HVAC game. Learn how to sharpen your skills, streamline your processes, and provide top-notch service to your customers. #HVAC #HVACTraining #Thoroughness #TechnicianTips #HVACSchool Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join HVAC expert Bert as he dives deep into the world of hoses, ports, and Schrader valves. Learn how to Save Those Fingies! Essential safety tips and techniques to protect your hands while working with pressurized systems. In this comprehensive how-to video, Bert covers: The history and importance of Schrader valves in HVAC Safety equipment and best practices Proper techniques for connecting and disconnecting hoses How to use core depressors and ball valves effectively Tips for maintaining and replacing valve cores Common mistakes to avoid and what to do in emergency situations Whether you're a seasoned pro or just starting out, this video is packed with valuable insights to keep you safe and efficient on the job. Don't miss Bert's practical advice on handling refrigerants and avoiding costly mistakes. Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bryan Orr from HVAC School as he introduces the must-attend event of the year: NCI's High-Performance HVAC Summit 2024! 🗓️ September 10-13, 2024 📍 Asheville, North Carolina Don't miss this opportunity to elevate your HVAC skills and business! The National Comfort Institute (NCI) brings together industry experts, including Bryan himself, to share invaluable insights on: Combustion and airflow techniques Implementing high-performance HVAC in your business Recruiting and retaining top talent Successfully installing and commissioning inverter equipment Whether you're a technician, service manager, or business owner, this summit is designed to boost your knowledge and profitability. Bryan will be presenting two key sessions: Hiring, recruiting, and retaining the best talent Tips for successful inverter equipment installation and commissioning 🔗 Register now at GoToSummit.com #HVACSchool #NCISummit2024 #HighPerformanceHVAC Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join us for an insightful presentation on Understanding Dual Fuel by industry expert Jim Fultz, recorded live at the 5th Annual HVAC/R Training Symposium. In this comprehensive session, Jim covers essential topics including: Basic heat pump operations Refrigerant storage and accumulator function The importance of matched systems Crankcase heater requirements Proper coil placement for dual fuel systems Defrost cycles and backup heat Determining balance points Whether you're new to dual fuel systems or looking to deepen your knowledge, this presentation offers valuable insights and practical tips for HVAC professionals. Jim shares real-world examples and addresses common challenges faced in the field. #HVACtraining #DualFuelSystems #HVACeducation Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bryan Orr as he unveils the impressive NAVAC NX1V digital manifold kit! In this video, we take a close look at this high-quality HVAC tool that's changing the game for technicians. What's in the box: - Digital manifold - Wireless temperature clamps - Micron gauge - Heavy-duty carrying case Key features: - USB-C charging for both manifold and vacuum gauge - Quarter-turn ball valves for precise control - High-quality sight glass and sturdy hook - Large, easy-to-read display - Compatibility with modern refrigerants, including A2Ls - Wireless temperature clamps with built-in displays - Pressure-rated micron gauge (up to 500 psi) Tech-savvy: - Connects to the NAVAC app for enhanced functionality - Four operation modes: Manifold, Leak Test, Evacuation, and Decay Test Whether you're a seasoned pro or just starting out, this video will show you why the NAVAC NX1V should be your go-to manifold kit. Don't forget to like, comment, and subscribe for more HVAC insights and tool reviews! #HVAC #NAVACTools #DigitalManifold #hvacschool Learn more at www.hvacrschool.com/nx1 Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In his presentation ''The Value of First Time Completion of PSC Motor Failures With Universal ECM'' Frank Granville from Regal Rexnord delves into the importance of first-time job completion when dealing with PSC motor failures. This presentation was recorded live during the 5th Annual HVAC/R Training Symposium. Frank explores how using universal ECM motors can increase efficiency, reduce callbacks, and boost profitability for HVAC contractors. Key topics covered: The cost of incomplete service calls Benefits of stocking universal ECM motors Comparing PSC vs ECM motor efficiency Step-by-step installation guide for ECM replacements Auto-sizing and rotation sensing technology Whether you're a seasoned HVAC pro or just starting in the field, this presentation offers valuable insights to streamline your motor replacement process and improve your bottom line. #HVAC #ECMMotors #HVACTraining #FirstTimeCompletion Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bert and Elliot in the exciting conclusion of our Refrigeration Basics series! In part 5, our expert instructors dive deep into troubleshooting techniques, covering: Common causes of low suction pressure Diagnosing airflow issues vs refrigerant charge problems Interpreting superheat and subcooling readings The five pillars of diagnostics High head pressure causes and solutions Learn how to quickly identify system issues using temperature and pressure measurements, and gain valuable insights into efficient diagnosis and repair. Whether you're a seasoned tech or just starting out, this video is packed with practical knowledge to enhance your HVAC skills. Don't miss this essential wrap-up to our comprehensive Refrigeration Basics course! Part 1 - https://www.youtube.com/watch?v=eKb_xbADAgA&ab_channel=HVACSchool Part 2 - https://www.youtube.com/watch?v=BhPls78ObH4&ab_channel=HVACSchool Part 3 - https://www.youtube.com/watch?v=2A9GRSu-1nk Part 4 - https://www.youtube.com/watch?v=ab7y6M6sb4o Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bert and Elliot as they continue their in-depth series on Refrigeration Basics with part 4 for Kalos techs. In this fourth installment, they dive deep into the crucial concepts of superheat and subcool: Understanding saturation and its importance in refrigeration Defining superheat and subcool How to calculate superheat and subcool The significance of these measurements in system performance Practical examples and real-world applications Tips for troubleshooting using superheat and subcool readings Whether you're a seasoned pro or just starting out, this lesson provides valuable insights into the core principles of refrigeration. Bert and Elliot break down complex topics with clear explanations and relatable analogies to help technicians grasp these essential concepts. Don't miss this opportunity to enhance your HVAC knowledge and skills. Like, comment, and subscribe for more educational content from HVAC School! #HVACtraining #RefrigerationBasics #SuperheatandSubcool #HVACschool

Join industry experts Chris Conway, Dustin Cole, Tim De Stasio, Chris Hughes, and Nikki Krueger as they dive deep into the world of dehumidification in this lively session from 5th Annual HVACR Training Symposium. Topics covered include: Dehumidifiers 101: Terminology and how they work with AC systems Why homes need dedicated dehumidification Installation best practices and challenges Sizing and ventilation considerations How to sell dehumidification to customers Get ready for an informative and entertaining discussion filled with real-world examples, practical tips, and a healthy dose of HVAC humor. Whether you're a seasoned pro or new to the field, this "hootenanny" has something for everyone in the world of humidity control. Don't miss this chance to learn from some of the best minds in HVAC as they share their knowledge and experience on this critical aspect of indoor comfort and air quality. #HVAC #Dehumidification #HVACTraining #indoorairquality Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this training class, Bryan Orr from HVAC School provides key facts and information for HVAC technicians about the transition to mildly flammable A2L refrigerants like R-32 and R-454B being adopted for residential and light commercial systems. He covers the reasons behind the phase-down of higher global warming refrigerants like R-410A, the differences between A2L refrigerants and propane, similarities and differences compared to R-410A, changes to equipment and components, best practices for handling mildly flammable refrigerants safely, evacuation procedures, leak testing, and more. This is a must-watch for any residential HVAC tech getting ready to work on new A2L systems in the coming years. Bryan dispels misinformation and fear-mongering around these new refrigerants while still emphasizing the proper precautions that should be taken. Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In Part 3 of the Refrigeration Basics series, Bert and Elliot take the classroom outside to apply what was covered in the previous lessons to actual HVAC equipment. They walk through the refrigerant circuit from the evaporator to the condenser, identifying each component and explaining the conditions of the refrigerant at each point. Bert provides hands-on demonstrations, having the techs feel the temperature differences before and after the metering device to illustrate the flashing/boiling process. They discuss concepts like flashing gas, pressure drops across metering devices, the effects of restrictions, and the importance of keeping coils clean for efficient heat transfer. Elliot points out diagnostic tricks like listening for certain sounds that can indicate flashing is occurring due to insufficient liquid supply reaching the metering device. Together, they reiterate the refrigerant states (pressure, temperature, phase) throughout the cycle, reinforcing key concepts through real-world examples. Part 1 - https://www.youtube.com/watch?v=eKb_xbADAgA&ab_channel=HVACSchool Part 2 - https://www.youtube.com/watch?v=BhPls78ObH4&ab_channel=HVACSchool Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

This video is one of the sessions from the 5th Annual HVACR Training Symposium: Scroll Compressors & Things to Check for Overheating by Jeff Kukert from Copeland. You can still purchase virtual tickets to ALL sessions at https://hvacrschool.com/events/5th-annual-hvac-r-training-symposium/. Scroll compressors compress refrigerant in the head, and high-side pressure is contained by the compressor's top cap, muffler plate, the fixed and orbiting scrolls, the IPR valve, and the floating seal. Low-pressure gas enters from the outer edge of the scrolls, and the high-pressure gas is discharged from the center. A fixed scroll doesn't move and is bolted to the main bearing housing, and the orbiting scroll oscillates within the fixed scroll, which compresses the gas during that motion. The scrolls have axial and radial compliance, which means they can lift up and down slightly (1 mm) and side to side, respectively. An Oldham coupling transforms the rotating motion of the motor into an orbiting motion on the orbiting scroll. A floating seal has a ridge that pushes against the muffler plate and separates the pressures during operation (it floats down and equalizes pressure when the compressor isn't running); it also acts as a protection device against excessive compression ratio. Oil lubricates all of the bearings, including the lower, main, and drive bearings, and it must be between the straddle bearing and the orbiting scroll. The scroll compressor also has various safeties, including the TOD (a bimetal disk that flexes in response to high temperature) and an IPR (a pressure safety). Prevention is the best cure when it comes to compressor failure. Best practices to avoid compressor failure later include purging and flowing with nitrogen, checking to make sure a system is leak-free, and pulling a deep vacuum on a system. Apart from using nitrogen while brazing, make sure you avoid overheating the metal based on the material (especially copper-clad steel) and use alloys with silver. When crankcase heaters are necessary, be sure to install them correctly, referring to the Copeland AE bulletins. Compression ratio is a major performance indicator, and high compression ratios cause high discharge pressures, which lead to overheating. Overheating causes oil to lose lubricity and break down, which leads to premature failure. Low suction pressure and high head pressure cause high compression ratios, and common causes include refrigerant losses, restrictions, pressure drops in the suction line, and inadequate airflow on the high side. Compressor performance sheets, available on the Copeland mobile app, can also give you some insight into the performance data we can yield from our compression ratios. Strategies that control compression ratio include liquid and vapor injection. Liquid injection is common in refrigeration and injects liquid refrigerant into the scroll set after a metering assembly; it has a DTC valve (mechanical) or a stepper valve (electronic). Vapor injection takes cool vapor refrigerant (from a heat exchanger that also increases subcooling) and inserts it into the compressor head via ports. We can also be diligent and check condenser airflow, verify subcooling (especially via a sight glass), ensure coil cleanliness, and make sure our electrical connections and components are in good working order. Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In part 2 of a series on Refrigeration Basics, Elliot and Bert team up to teach a class about how HVAC and refrigeration systems work. In this part of the class, they discuss the functions of the main components in the refrigerant circuit, states of matter, and how to interpret your temperature measurements with that knowledge. Part 1 is available at https://www.youtube.com/watch?v=eKb_xbADAgA&ab_channel=HVACSchool. There are four main components in the typical refrigeration circuit: an evaporator, a compressor, a condenser, and a metering device. Each of these components manipulates the pressure or temperature of the refrigerant inside it. For example, the metering device drops the pressure of liquid refrigerant going into the evaporator; when this happens, a small temperature change occurs, and the pressure drop also causes some of the high-pressure liquid refrigerant to boil off. The components are connected by the suction, discharge, liquid, and sometimes expansion lines. Matter comes in three phases: solid, liquid, and vapor. We should never see solid refrigerant in an HVAC system, but the refrigerant changes between the liquid and vapor states; evaporators transform liquid refrigerant to vapor, and condensers transform vapor refrigerant back to liquid. These phase changes usually occur at specific temperatures, but we can manipulate the pressure to raise or lower the boiling point. That's why we can have cool vapor and warm liquid with roughly the same amount of energy despite the temperature differences. Saturation temperature is the temperature at which the refrigerant either boils or condenses, and it varies based on pressure. The suction pressure is the pressure of the cool, low-pressure vapor refrigerant in the suction line. Its pressure should be the same from start to finish, and we can take the pressure reading at the suction service port. A common rule of thumb is that the suction saturation temperature should be about 35 degrees below the indoor ambient temperature, give or take about 5 degrees. Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

This video is one of the sessions from the 5th Annual HVACR Training Symposium: "So you know how to fix it... Now how do you sell it?" by Dominick Guarino. You can still purchase virtual tickets for ALL presentations at the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Dominick identifies our industry's issue with delivering substandard BTU capacity and explains how high-performance HVAC (especially following the National Comfort Institute or NCI's model) addresses this epidemic. You can deliver high performance by measuring static pressure, airflow, BTUs, refrigerant charge, and combustion efficiency; the system should be tested and balanced. This approach has benefits for homeowners and contractors alike. This presentation outlines three distinct lead types: traditional replacement, service-generated call turnovers, and homeowners seeking solutions. He emphasizes the importance of customer education in the sales process, coining the term "educational selling." Dominick delves into the specifics of each lead type, providing actionable steps for HVAC professionals. Key topics include conducting static pressure tests, using tools like the True-Flow Grid and airflow hoods, and involving customers in the diagnostic process. He stresses the importance of differentiating your company through these practices. A case study of a new home with severe HVAC issues underscores the need for thorough diagnostics and system optimization. Dominick also introduces NCI's system certification process, which proves performance to homeowners. Additionally, he highlights the crucial role of building science in HVAC, stating that "a home is the load side of the HVAC system." This presentation is essential for HVAC professionals looking to improve their sales strategies, enhance customer satisfaction, and deliver high-performance systems. Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In part 1 of a series on Refrigeration Basics, Elliot and Bert team up to teach a class about refrigeration basics. They discuss the basic scientific principles that make HVAC systems work and how they work with the components most residential HVAC systems will have. There are four main components: compressor (high-temperature; pressure increaser), condenser (heat rejector), metering device (pressure dropper), and evaporator (heat absorber). When you start by memorizing components and their order, you can start to absorb information about HVAC systems with greater ease since you will have the vocabulary at your disposal. Pressure is one of the main driving forces of the HVAC refrigerant circuit; it is the force exerted on an object. It may be measured in absolute pressure (PSIA) or gauge pressure (PSIG), the latter of which deducts atmospheric pressure (14.7 PSI). We usually use PSIG in the field; we may use PSIA for some PT charts and calculating the compression ratio. In the HVAC industry, we primarily measure air pressure in inches of water column ("wc or in. wc.), refrigerant pressure in PSIG, and vacuum pressure (in microns; 1/1,000,000 inches of mercury column). Temperature is an average measurement of molecular velocity (how fast molecules are moving). It is not the same thing as heat; heat is the amount of energy a substance has, not the average speed of the molecules. Something may be cold to the touch but still have heat. In the HVAC industry, we are moving heat; temperature is an indicator of it, but it's not the exact same thing. Temperature measurements might be wet-bulb or dry-bulb. Dry-bulb temperature only accounts for sensible heat, and the wet-bulb temperature accounts for latent heat (moisture or humidity) and is usually cooler than the dry-bulb temperature. The compressor manipulates temperature by manipulating pressure according to the Ideal Gas Law (PV = nRT); as pressure rises, the temperature also rises. Temperature also decreases as pressure decreases, so the metering device drops the refrigerant pressure before it enters the evaporator again. The Second Law of Thermodynamics states that hot goes to cold; heat moves from hot to cold and will attempt to continue to do so until both objects are at the same temperature (thermal equilibrium). HVAC systems use the evaporator as a means of heat transfer; heat from the space is moved into the colder refrigerant, and refrigerant that is hotter than the outdoor temperature gives off that heat to the cooler space. Imbalances in pressure will cause the refrigerant to move, and imbalances in temperature will allow heat to move. Voltage, or electrical pressure, also follows a high-to-low rule. Whenever there is a difference in electrical potential, electrical energy will move from a higher concentration to a lower concentration due to the energy imbalance. Buy your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this informative session from the 5th Annual HVAC/R Training Symposium, Matthew Taylor draws from his 25 years of experience in the supermarket world to provide an Introduction to Market Refrigeration for HVAC Techs. Matthew covers the key differences between residential/commercial air conditioning systems and the parallel rack refrigeration systems found in supermarkets. He explains how the core refrigeration cycle concepts are the same, but the physical setup, components, and control strategies differ in market refrigeration. Some of the topics covered include: Major components like compressor racks, condensers, and evaporator cases Control systems and sensors for precise temperature/pressure regulation Maintaining different evaporator temperatures for product zones (freezers, coolers, etc.) Defrosting strategies for evaporator coils running below freezing Reclaim systems that recycle compressor heat for hot water or dehumidification Split condensers and fan staging for low ambient operation Whether you're an HVAC tech looking to understand grocery store refrigeration better or just interested in learning about this specialized area, Matthew's engaging presentation provides a clear overview. The session allows for participant questions throughout. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join HVAC expert Bryan Orr as he takes you on a visually stunning Refrigerant Lines 3D animated journey through the refrigerant lines of split system AC units and heat pumps. In this informative video, you'll gain a deep understanding of the four crucial refrigerant lines and how they relate to pressure, temperature, and the overall refrigerant cycle. Through detailed 3D animations, Bryan will walk you through: The Suction Line - Carrying low-pressure cool refrigerant vapor away from the evaporator coil towards the compressor. The Discharge Line - Transporting hot, high-pressure superheated refrigerant vapor from the compressor to the condenser. The Liquid Line - Responsible for moving high-pressure subcooled liquid refrigerant from the condenser to the metering device. The Expansion Line - Existing in some systems to carry the saturated refrigerant mixture between the metering device and evaporator. Bryan's clear explanations, coupled with vivid 3D visuals, will help you visualize the pressure and temperature differences between these lines. You'll understand critical concepts like superheat, subcooling, and their importance for optimal system performance. Whether you're an HVAC technician, student, or enthusiast, this video is a must-watch for anyone seeking to deepen their knowledge of the refrigerant cycle in a visually engaging way. Join Bryan and let HVAC School's 3D animated exploration simplify your understanding of these essential refrigerant lines. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-sto

This presentation is one of the sessions from the 2024 HVACR Training Symposium: The Quality Installation Conundrum with Brian Feenie. Technology has recently evolved to provide transparency; in the HVAC world, apps like measureQuick allow us to share important data with customers and educate them, which provides a lot of value and builds brand loyalty. Brian draws parallels between the automotive industry's focus on transparency, consistency, and added value - and how HVAC contractors can adopt similar principles. Brian also covers various roles and personalities at play in HVAC sales transactions, particularly the hero/fixer (technician) and the buyer/holder of money (homeowner). Brian discusses the impact of callbacks on profitability and how implementing standardized processes using tools like measureQuick and ACCA QI certifications can mitigate callbacks and build customer trust and loyalty. measureQuick can give Vitals Scores, which are like report cards of an HVAC system's performance; this feature shows customers what their system is doing well and what it can improve on, which helps with transparency and trust. It's also a verification tool for ACCA QI certification. The ACCA QI (quality installation) verification builds confidence and provides peace of mind for the customer. Verified equipment operation (VEO) is an additional certification that acknowledges that a system meets high standards in airflow and other performance indicators. Brian provides a compelling vision for proving your quality installs, exceeding customer expectations, and securing a competitive edge. Whether you're an owner, technician, or part of the sales team, his session will challenge you to raise the bar and explore innovative ways to deliver unmatched service and transparency to homeowners. The motto of ACCA QI certification, which perfectly captures Brian's session, is: "Install it. Test it. Prove it." Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

This presentation is one of the sessions from the 2024 HVACR Training Symposium: Humility in Thought Leadership with Bryan Orr. Most of the symposium speakers are thought leaders; they are influential educators and mentors whose ideas and practices reach a large amount of people. To be truly effective, thought leaders need to have empathy and understand how others think; they demonstrate professional pride and personal humility, not personal pride and professional apathy. Influence is also a part of being a thought leader, but it's not a prerequisite; service is the more important aspect, as it aims for an end result that makes someone else's life better. (Bryan compares serving others to what it means to "deserve" something.) Thought leaders need to assess how they feel when others are in the spotlight: happy or protective. If we're happy to support someone else who is getting credit for the causes we believe in, we are putting those causes first, not our egos. Thought leaders must also be careful about keeping their egos in check when presented with new information; if we are truly dedicated to the trades and the causes being championed, our ideologies need to be able to adapt to new information. Our opinions should only matter when we make decisions that affect us or when we are asked. It is not our place to give unsolicited advice or offer opinions that tear others down. Opinions offered when nothing is at stake on our end don't mean anything to the broader goal. Similarly, introspection done for selfish reasons or to justify certain behaviors is not meaningful, whereas introspection done in service of others is worthwhile. Some common not-so-humble thoughts deal with the same idea of "deserving" that Bryan touches on throughout the presentation, including "I am entitled to be heard." The same goes for people who believe that they are integral to a cause or movement, not just fortunate to be surrounded by others who care equally about the cause. Humility is NOT self-serving. Imposter syndrome is a common occurrence in leaders, but Bryan argues that it isn't necessarily a bad thing. It pushes us into authenticity, vulnerability, and growth, but it can also make us become defensive and withdraw. The Dunning-Kruger effect provides an explanation for imposter syndrome; when we know very little about a topic, we tend to be confident in it. When we realize how little we know, we lose our confidence (i.e., imposter syndrome). If we commit ourselves to continuous learning, we can regain our confidence and obtain more knowledge; we reach the plateau of sustainability. It is possible to slip backward on the Dunning-Kruger scale, often due to unbridled idealism or a disconnect from reality. Intentionality and focus are good, but they can also keep us from acknowledging other viewpoints (and reality). We have a lot of positive communication nowadays in the industry, but we do our best when we all work as a unit with a common goal and set aside our egos. The HVAC industry will make the most progress when all of us listen to others and aim to serve them instead of focusing on what we deserve. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this AC Types 3D video, we will go over the variety of AC system types and their common applications. Split AC systems and heat pumps generally consist of two main parts: an indoor unit (with an evaporator and metering device) and an outdoor unit (compressor and condenser) connected by linesets (the suction or vapor line and the liquid line). Heat pumps also have a reversing valve that can reverse the flow direction. These systems may be paired with a furnace (if a heat pump is paired with a furnace, it will be called a “dual-fuel” system). Package systems combine the evaporator, compressor, and condenser into a single outdoor unit. These units may either be on the ground or on rooftops and rely on ductwork to move air into the unit from the structure and out of the unit back to the structure. Packaged terminal air conditioners (PTACs) and vertical terminal air conditioners (VTACs) are self-contained units common in hotels and apartments, though with reduced efficiency. They require an outdoor penetration for heat exchange. Window units are also self-contained and can exchange heat between the indoors and outdoors. Ductless or mini-split units and variable refrigerant flow (VRF)/variable refrigerant volume (VRV) systems are usually split systems that move BTUs efficiently in concentrated spaces (such as individual rooms). Ductless mini-splits often have one head, and VRF/VRV systems often have multiple heads that can serve multiple rooms. They are best in applications where duct installation is impractical, high efficiency is desired, or precise temperature control is needed. In many mini-splits, the metering device is outdoors, so there are two cold lines that require insulation, not just one. Water-source or geothermal heat pumps use the stable temperatures of water or the ground, not air, to exchange heat. All components are indoors, including the compressor. While highly efficient, they need a lot of space so that we can create the well or ground loop needed for heat exchange to occur. Swamp coolers (evaporative coolers) rely on adiabatic cooling to reduce the temperature of incoming air. As air moves over the wet cooling pad, some of the water absorbs heat from the air, leaving the air cooler as it leaves. These are common in hot, dry climates, and microbial growth is a concern that we must consider. Monoblock heat recovery chillers contain all components in a single unit, utilize secondary fluids, and produce heated and cooled fluid simultaneously. These units may be used for heating, cooling, dehumidification, and domestic hot water. Their designs are a bit more complicated, and they require you to consider the placement of buffer tanks where the heated and cooled fluids are stored. Each AC system type has its own advantages, applications, and ideal installation conditions. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this 3D video about the refrigerant circuit, we dive deep into the fundamental principles and key P1 components of the basic refrigerant circuit, which is the core of cooling systems, both in refrigeration and air conditioning. We explore two key concepts: 1. Heat moves from higher to lower temperature. 2. The relationship between pressure and temperature - higher pressure means higher temperature, and vice versa. These principles guide the entire refrigeration process and help us understand what's happening inside the system. The video then takes us through the components of the refrigeration cycle step-by-step: - The compressor, which is the "heart" of the system, increases the pressure and temperature of the refrigerant. - The condenser rejects the heat from the refrigerant, causing it to condense into a liquid. - The metering device then dramatically drops the pressure of the refrigerant, cooling it down further. - The evaporator is where the "magic" happens - the cold refrigerant absorbs heat from the environment and boils, effectively cooling the space. By understanding this continuous refrigerant cycle, we can see how refrigeration and air conditioning works as we rely on these systems to provide the cooling every day. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

This video is a 2024 HVACR Training Symposium session by Andy Holt - "Fix Your Customer 1st, Then Fix Their System." Andy Holt specializes in customer service and has a unique approach to training through his Outdoor University program. The most important piece of customer service advice is to approach everything from the customer's point of view. This piece of advice holds true in sales consultation and even extends to the way you answer the phone. It's important that the customer feels they've made the right choice by choosing your company, and for that reason, the beginning of each call should be deliberate, positive, and done with the end result in mind. Andy likes to say that we're not in the HVAC business, we're in the people business. Soft skills that apply in any people-centric career also apply in HVAC, including timeliness and the common courtesies associated with it. Organization in the truck is also a great way to deliver services timely, and showing respect for the customer's home by being clean and orderly is also a green flag. Customers aren't tuned into the technical aspects of the work you do; they care about how you made them feel and what you did for them; taking care of customers ensures that you have a consistent income for a long time. One of the best ways to make a good impression on your customers is to be a good listener who is eager to please them. Keeping a notepad on hand helps technicians take notes about the customer's comfort problems and shows the customer that they are being listened to. The notepad is also good for making sure technicians are thorough in their calls, and the thoroughness should also extend to our diagnostic processes. Being able to communicate our processes to the customer is also important for transparency, especially regarding pricing. When we communicate our findings, we should focus on the most critical items that affect the customer's comfort first. Andy also discusses onboarding new technicians and setting them up to be successful with their customers (and in the company culture as well). Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Roman Baugh gives the Kalos techs an introduction to VRV/F systems. Variable refrigerant flow (VRF) or volume (VRV, Daikin) systems are a specific type of HVAC equipment invented by Daikin. The same superheat and subcooling principles apply, though there are a few more moving parts. VRF systems are more like VFDs that take AC voltage, convert it to DC voltage, charge capacitor banks with the DC voltage, and use pulse-width modulation to run the compressor at different hertz (at 168 different speeds). The variable-speed nature moves varying amounts of refrigerant to meet the exact demand of indoor units and run efficiently. These systems supply a specific amount of refrigerant to a given indoor unit to meet its required capacity. The indoor and outdoor units constantly communicate (via a PID loop) to make this possible. VRF systems may use either 2-pipe or 3-pipe heat recovery. Those pipes represent refrigerant lines moving into and out of the heat recovery box, which generates the liquid needed for the indoor units. It has a branch collector box that skims refrigerant. Hot gas goes to the unit(s) calling for heating, and it condenses to a liquid in the indoor heat exchanger, which then goes to the unit(s) calling for cooling. Capacity varies widely among VRF systems. In some cases, two outdoor units can handle a combined 40 tons of capacity. Higher-capacity systems have higher compressor and fan speeds, usually with larger compressors. Compressors and inverter boards may be refrigerant-cooled (using liquid refrigerant). VRF indoor units vary quite a bit in shape and size, coming in wide and slim, ducted and ductless varieties. Roman covers the features, advantages, and disadvantages of existing models as well as the unit nomenclature and clearances. Roman also covers copper tubing, including REFNET kits and Y joints, as well as proper installation of those and some general brazing tips to reduce turbulence. He also discusses oil management, especially as it relates to piping consideration and refrigerant turbulence in the copper tubing, as well as oil return mode and traps. On the installation end, it is critical to remove the shipping bracket from the compressor and eliminate cross piping. Flaring, pipe lengths, pipe diameter, and proper piping support are other considerations for VRF piping and installation. Flowing nitrogen while brazing is important in all systems to prevent the buildup of oxides and clogged screens, but the copper oxides can damage electronic expansion valve needles, which can lead to oil loss in the compressor and catastrophic failure. Roman goes through the process of installation, including the pre-construction phase and jobsite considerations when installing VRF systems. He also explains the difference between communicating systems (including VRF/V systems) and 24v systems, and he covers control circuit terminal designations on VRF systems. This video also covers very basic elements of service and troubleshooting, including how to think about using the correct tools for the job. The basic starting points for VRF troubleshooting include temperature in and temperature out. Temperature sensors are common fail parts, and it's important to stay on top of those, as failed temperature sensors can cause catastrophic failure in the long run. Roman also ends on a note about the importance of reading the manual to assist with troubleshooting. He also explains the importance of pulling and weighing out the refrigerant charge before adding charge to a VRF system. Roman's tech tip about troubleshooting inverter boards: https://hvacrschool.com/troubleshooting-inverter-boards/ Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Bert interviews Tony Gonzalez at the Fieldpiece Booth at the 5th Annual HVAC/R Training Symposium about their exciting new line of VCRTs (Valve Core Removal Tools). Tony walks through the three models - the good, better, and best versions: The VC1 is the basic model but with improvements like a swappable 1/4" or 5/16" fitting end and an enhanced capture mechanism so the valve core can't fall out. The VC1G adds a sight glass so that you can visually confirm when the valve core is captured. The VC2G is the premium model with the sight glass, plus an integrated micron gauge port and a comfort spinner to make removal easier against system pressure. Tony highlights how these new VCRTs address major tech pain points, like not knowing if the valve core is actually out, valve cores getting dropped, and the struggle of removal against system pressure. The new designs provide confirmation, secure capture, and improved ergonomics. He also discusses their new colored hose system with interchangeable color tags for easy identification of line sets. Plus, they're ahead of the game with fittings ready for the new A2L refrigerants coming. Don't miss this inside look at HVAC tool innovations designed to make your job easier! Like, comment, and subscribe for more helpful HVAC/R content. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

This 3D animation will go through the 101 of of relays in HVAC systems, exploring key components like the coil and contacts, as well as how relays work and why we use them. This 3D video also covers components that are similar to relays. Relays are electrically operated switches that generally allow a lower-voltage control circuit to control higher-current circuits to help turn things on and off safely. The main component of a relay is a coil or electromagnet, and there is also a series of electrical contacts. When current passes through the coil, it generates a magnetic field that moves a metal armature, opening or closing the attached contacts (also known as switches or contact points). These contacts allow or disrupt the flow of electricity, depending on whether they're closed or open, respectively. These contacts may be normally open (NO) and close when the coil is energized or normally closed (NC), which open when energized. Relays provide isolation between the control circuit and the circuit being controlled. That is why we can control 240v components with much safer 24v controls in residential HVAC systems. We must pay attention to the coil or control voltage rating, contact voltage, and amperage ratings to make sure we have the right relay for the application. Two common relay types we see in HVAC include 90-340 and ice cube relays. 90-340 relays are double-pole, double-throw (DPDT) relays with two sets of contacts (one NO and one NC in isolated rows, making them "dry contacts") and eight terminals; they are multi-purpose relays that can control components that draw less than 15 amps, like fan motors. The coil pulls the switch contacts to change the states of the contacts. Ice cube relays have a clear casing, a coil, an armature, and contacts. Some controls that function like a relay include contactors, which have contact points and can handle current up to 40 amps and often control compressors; their contacts are normally open and close upon energizing. Motor starters are like large contactors that come with an overload and are designed for starting and stopping motors, providing control and overload protection. MOSFETs also work similarly to relays, but they have different components and switch electronically rather than physically, and their three components are the gate, drain, and source. Stack sequencers use physical components to control sequences in electrical heaters and fans; they consist of a heater and a bi-metallic disc for on/off delays. You can test many of these controls for continuity with a multimeter. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join moderator Bert as he sits down with Ashley Lynds and Becca Stamey to discuss Field Favorites at the Refrigeration Technologies Booth during the 5th Annual HVAC/R Training Symposium. In this interview, Ashley and Becca showcase some of Refrigeration Technologies' most popular products and field favorites, including their new Heat Shield heat blanket for protecting surfaces when brazing, their ubiquitous Big Blu expandable foam, and Super Seal leak sealant. Ashley does a demonstration of the Heat Shield, showing how it can protect surfaces when brazing up to 2500°F. She also talks about the convenience of the built-in slit to slide it over copper lines. They discuss the versatility of Big Blu foam for various applications since it's non-toxic and safe enough to even use for grilling. And they cover how durable Super Seal is after extensive drop testing. Join Bert and the team from Refrigeration Technologies to learn about these field favorites and how they can upgrade your HVAC service calls! Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join us as we are unboxing the new NAVAC NR7 recovery machine, which is lightweight, compact, swift, and A2L-compatible. Learn more at https://navacglobal.com/ or preorder yours from TruTech Tools today at https://trutechtools.com/navac-nr7-brushless-a2l-compatible-refrigerant-recovery-unit/ (and use the offer code GETSCHOOLED at checkout for a discount!). The gauges on the NR7 are filled with glycol, which reduces flutter. Its operation is managed by a single dial, which can close the machine, recover refrigerant at multiple speeds, and purge the machine all in one. The NR7 also has a condenser coil with multiple rows, which cools the refrigerant during recovery, and it has great airflow to move the most refrigerant possible. Recommended accessories include a charging scale, large hoses, and the Rapid-Y connection fitting, which allows you to connect two 3/8" ports into a single 1/4" port. NAVAC also has a four-port hose holder (FHH4) that has multiple connection points to keep your hoses from getting contaminated between uses. Note that NAVAC hoses are for vacuum and recovery, not charging, so they don't come with core depressors at either end (but they do come with extra O rings!). You can connect the accessories by attaching the hoses to the Rapid-Y and the 3/8" ports and attaching the Rapid-Y to the recovery machine at the 1/4" port. The hoses need to be connected to the system with a core removal tool. For best results, connect one hose to the liquid line service port and the other to the suction line service port. Then, connect a hose from the recovery machine to the recovery tank. Once your hoses are connected, start your machine and slowly throttle the flow into the tank via the control knob or dial. When you've finished, purge your machine. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join moderator Bert as he sits down with Andy Holt at the 5th Annual HVAC/R Training Symposium for an insightful booth interview. In this candid discussion, Andy shares his unique perspectives on the importance of communication in the HVAC technician role. Andy elaborates on his company's innovative Outdoor University program which takes technicians out camping for immersive communication training. He explains how technical prowess alone is not enough - being able to clearly communicate with customers is essential. Using an interactive model, Andy examines different personality types and relationships, highlighting constructive and destructive communication techniques. The two also touch on software tools for financing and proposals that can improve the customer experience during replacement sales. Bert applauds Andy for selflessly giving his time to speak and invest in the next generation of HVAC technicians. Viewers will gain practical tips for thoughtful engagement with customers, coworkers and management. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bert as he sits down with HVAC expert Ed Janowiak at the ACCA Booth for a casual yet insightful conversation during the 5th Annual HVAC/R Training Symposium. In this interview, Ed shares what brought him to the symposium originally and some of his favorite memories over the years of attending. He discusses meeting symposium organizer Brian for the first time in person after having only talked on a podcast previously. Ed also talks about how he's gotten to know so many people in the industry through the years at the annual event. From late-night conversations to making lifelong friends, Ed gives viewers a glimpse into the heart of the HVAC community. You'll also hear Ed's take on the symposium versus other industry events and what makes this one special regarding the opportunities for quality conversations. He shares advice for those looking to get the most out of their conference experience when it comes to networking and connecting with others. So join Bert and Ed at the ACCA Booth for this genuine life chat all about making industry friends, giving back to the community, and continuing education among peers. Consider hitting subscribe and the notification bell so you don't miss out on future interviews! Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join us for our chat with Russ King of Kwik Model 3D at his booth during the 5th Annual HVAC/R Training Symposium. Russ gives an overview of his award-winning duct design software that imports floor plans into a 3D modeling environment similar to Minecraft. He explains how it integrates with QB Carson and new phone app technology to easily create digital floor plans of existing homes for accurate HVAC load calculations. Russ introduces Kwik Model 3D's new DIY Load program that allows homeowners to scan their own homes and receive a load calculation file that contractors can use for bids. He discusses the reactions to empowering homeowners with DIY load counting and how it relates to the switch to heat pumps. Overall, it's a great conversation about bringing residential HVAC design into the 21st century through game-changing software. Let us know what you think, and don't forget to like, comment, subscribe, and hit the bell for more HVAC training videos! Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bert as he interviews Eric Kaiser, famous technician and legend from TruTech Tools, at their sponsor booth during the 5th Annual HVAC/R Training Symposium. In this candid discussion, Eric shares details about TruTech Tools' commitment to providing reliable tools and education to HVAC/R professionals. Topics covered: TruTech Tools' focus on stocking and shipping quality tools technicians can rely on Options for getting support if something breaks Competitive pricing to support hardworking technicians Ongoing efforts to provide more technical education on tools and best practices The value of TruTech Tools for those just getting started in the field Eric also reflects on his experience as the surprise most popular speaker at this year's symposium and commits to coming back next year (with fewer sessions)! We hope you enjoy this insider view into the vendor side of things at this annual industry event. Let us know in the comments if you found Eric's perspectives valuable and what you'd like to see in future HVAC/R Training Symposium coverage. Don't forget to subscribe and ring the bell to stay up to date with all of our latest videos supporting the HVAC/R community! https://www.trutechtools.com/ Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join host Bert at the 5th Annual HVAC/R Training Symposium as he chats Leading With Intent with Tyler Nelson at the Sauermann booth. Tyler talks about Sauermann's flagship combustion analyzers - the ZERO 30 model for residential/light commercial use and the ZERO 130 model for residential/commercial applications. He highlights key features like long 5-year oxygen and NOx sensor life, centralized life indicators to show remaining sensor life, end-of-life indicators, programmable pump cut to prevent CO sensor overload, parameter alarms for furnace/boiler setup, color-coded connections, customizable display, mobile app connectivity and more. Tyler also shares some practical tips from his symposium talk, like using your analyzer to protect yourself and customers by monitoring carbon monoxide levels and checking for a proper 20.9% intake of oxygen to prevent corrosion and damage to HVAC systems. Get an insider view of the latest combustion analyzer tech and field knowledge from Sauermann's Tyler Nelson at the 5th Annual HVAC/R Training Symposium. Remember to like, comment, and subscribe for more HVAC content from HVAC School! Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bert and Jeffrey Cherif from JB Industries as they discuss brand new probe sets at the JB Industries booth during the 5th Annual HVAC/R Training Symposium. In this video, Jeffrey shows off JB's latest Climate Glass probe set featuring an integrated digital display for quick on-the-spot readings. Key features highlighted include pressure passthrough capability for easy refrigerant charging, robust replaceable sensors, multiple head unit compatibility, and easy access for cleaning and maintenance. Jeffrey also provides a first look at JB's new micron gauge designed for use at any orientation. Tune in for an inside exclusive on the latest test instruments hitting the market and insights direct from the JB team on what sets their offering apart. This is an interview HVAC techs and contractors won't want to miss! JB Industries website: https://www.jbind.com/ JB Industries Instagram: jbindustries_hvac JB Industries Youtube: @jbindustries8325 Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bert as he conducts an exciting booth interview from the 5th Annual HVAC/R Training Symposium with special guest Jeffrey Cherif from JB Industries. In this video, Jeffrey showcases JB Industries' brand new lineup of rugged, American-made vacuum pumps now featuring DC power. Jeffrey highlights key pumps like the Platinum 12 CFM, great for commercial applications, the lighter 8.4 CFM pump, now 5 lbs lighter with dual voltage flexibility, the value-priced Eliminator pump, and the innovative Flex battery-operated portable pumps. He also discusses customization options, addressing contractor concerns on equipment transitions with new refrigerants and JB's commitment to US manufacturing. If you're looking to upgrade your vacuum pump arsenal with the latest 2021 models, don't miss Jeffrey's in-depth tour of JB Industries' reliable and now DC-powered vacuum pump offerings. Check out the video to learn more about "Vacuum Pumps Just Got Better" with JB Industries! Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bert and special guests Mallory David & Jim Jansen from Parker Sporlan at their booth during The 5th Annual HVAC/R Training Symposium! In this interview, they showcase two braze-free Parker solutions—ZoomLock Max push-to-connect fittings for refrigeration and AC applications and ZoomLock Push, their alternative to SharkBite push-to-connect plumbing fittings. Mallory & Jim detail proper copper pipe prep, demonstrate installing ZoomLock Max fittings using the 3-point crimping tool, and test pressure ratings up to 870 psi. They also discuss ZoomLock Push's removable & non-removable options and flex connectors for mini-split systems. Get answers about vibration testing and durability and hear common skepticism from HVAC techs regarding these innovative Parker Zoomlock fittings and their impressive capabilities! Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bert and special guest Keith Keller from NAVAC as they face off in an epic pipe bending skills competition at the NAVAC booth at the 5th Annual HVAC/R Training Symposium. Watch as Keith puts his speed and accuracy to the test while bending, swaging, and flaring 5/8" copper tubing using NAVAC's innovative, battery-powered tools. After Keith sets a seemingly unbeatable time of 1 minute 20 seconds, see if Bert has what it takes to beat the record. The competition heats up as Bert struggles with battery changes and Keith's playful trash talk. Will Bert's last-minute switch save his time? Find out who conquers the course in the fastest time and wins a free flaring tool kit prize pack from NAVAC. Stick around for Bert and Keith's good-natured analysis of the nail-biting matchup. Whether you're a working technician looking to step up your bending game or just enjoy some hilarious HVAC hijinks, this battle is one you don't want to miss! Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join us at the 5th Annual HVAC/R Training Symposium as Bert conducts an exciting booth interview with Brad Adcox from NAVAC. In this video, we discuss NAVAC's newest additions to their recovery machine lineup. Brad gives an overview of NAVAC's big commercial 4-cylinder unit, perfect for large equipment. He then shows off the slimmed-down 2-cylinder model, ideal for commercial/residential technicians. The star of the show is NAVAC's brand-new NR7 recovery unit. Weighing only 28 lbs, it features triple-stacked condenser coils and an oversized fan for maximum cooling and recovery speed. Stick around to hear Brad's real-world feedback from technicians testing these machines in the field. We also talk about the best uses and applications for each recovery unit size. This is an insightful interview you won't want to miss! Special thanks to Brad and the team at NAVAC for joining us at the symposium and showing their support for HVAC/R education and training. Let us know what recovery machine caught your eye in the comments! Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Bert is back at the 5th Annual HVAC/R Training Symposium, this time speaking with Mark Hucko at the INFICON Booth. INFICON is showcasing Everybody's Favorite Tool, their impressive line of leak detectors that technicians have relied on for precision and accuracy. Mark provides an overview of their variety of leak detectors for different applications and gases. He demonstrates their infrared refrigerant leak detectors that can not only detect leaks but also quantify the leakage amount in parts per million. This allows technicians to hone in on the exact location of leaks very quickly. Mark also shows how the detectors can be switched between different sensor types to test for various refrigerant gases. If you're in the market for an essential leak detection tool that technicians love, check out what INFICON has to offer. Don't forget to like, comment, and subscribe to HVAC School for more helpful videos and content! Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join us as Bert interviews Mark Hucko from INFICON at their booth during the 5th Annual HVAC/R Training Symposium. Mark highlights some of INFICON's latest innovative and disruptive tools for HVAC/R technicians. We discuss INFICON's new WayTech Pro scale, which allows precise charging down to 3 grams, can now handle larger commercial tanks up to 275 lbs, and has added ports to enable critical charging of small canisters - no more need for a separate scale! Also featured is INFICON's new FlueMax combustion analyzer, which was launched in October 2023. It provides a full-screen display of measurements and allows reporting via a QR code, eliminating the need for printed receipts. If you're an HVAC/R tech looking to upgrade your tools, you won't want to miss seeing these latest product launches from INFICON in action. Special thanks to Mark and the team at INFICON for showcasing these exciting new tools. Let us know in the comments if you have any questions! Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bert as he talks with Brad Adcox from the NAVAC Booth at the 5th Annual HVAC/R Training Symposium. In this video, Brad showcases some of NAVAC's quick, easy, and efficient tools, including their automatic tube flaring machine, which creates perfect flares every time without any guesswork. Brad also demonstrates NAVAC's new hydraulic tube expander, which has an automatic reset so you don't over-expand copper tubing. He also gets us primed to hear about NAVAC's new beast of a recovery machine. NAVAC has been a huge supporter of HVAC School events for years, and it's great to catch up with Brad and see the innovative new products NAVAC has on display. If you're looking to upgrade your HVAC/R tools, you won't want to miss this insider's look at what NAVAC has cooking for 2024. Drop a comment sharing your favorite NAVAC tool or any questions for Brad. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this booth interview from the 5th Annual HVAC/R Training Symposium, Bert moderates a conversation with Don Gillis from Chemours, a company that makes refrigerants. Chemours was formerly part of DuPont until 2015. Don is well-known as an educator in the HVAC/R field and has presented at the symposium multiple times. During the interview, Don discusses Chemours' new 454 series of refrigerants - 454A, 454B, and 454C. He explains that R-454B is designed for comfort cooling applications, replacing R-410A in new equipment. R-454A is optimized for medium-temperature applications under 200 lbs, while R-454C targets lower GWP for low-temperature systems over 200 lbs. Don highlights that while the components are the same across the 454 refrigerants, the ratios are adjusted by scientists to hit targeted GWP levels under different charge sizes. He also previews an upcoming main-stage A2L refrigerant presentation with a colleague. The discussion touches on refrigerant tanks being gifted to tie down sponsor tents this year, as well as the symposium's growth into a key industry education hub. Don expresses gratitude for the opportunity to give back through events like this. Tune in to hear the latest refrigerant insights from an experienced voice at a leading chemical manufacturer supporting sustainable HVAC/R solutions. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join us at the 5th Annual HVAC/R Training Symposium as Matthew Bruner conducts a booth interview with special guests from ESCO Institute, including Daniel Mendoza, Eugene Silberstein, and Ty Branaman. We discuss ESCO's recent growth and expansion efforts, such as translating educational materials into Spanish and reaching out to the Hispanic community. The guests emphasized the importance of bringing more resources and training opportunities to HVAC/R technicians in the field. They highlight the power of teamwork and communication in moving the industry forward. Stick around for a lively discussion about plans for the upcoming conference and predictions for a high-energy year ahead. If you're interested in learning more about the future of HVAC/R education from these passionate industry leaders, don't miss this insider's view from the ESCO Institute booth! Check out ESCO Institute's HVACR Learning Network at https://hvacr.elearn.network/. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bryan Orr as he interviews Copeland Compression experts Josh Souders and Lancelot Sharpe at AHR 2024 to learn all about Copeland's newest compressor technologies. Josh introduces Copeland's next-generation two-stage and variable speed compressors, explaining the benefits of each in terms of efficiency, comfort, and reliability. He also discusses Copeland's new variable frequency drive designed specifically for use with variable speed compressors. Lancelot then gives an inside look at Copeland's brand-new oil-free centrifugal compressor featuring a revolutionary air lift bearing system. He discusses the development process over the past 7 years and what makes this compressor stand out from typical magnetic bearing centrifugal compressors in terms of simplicity and reliability. If you're interested in hearing about the latest innovations in compressor technology straight from the experts at Copeland, don't miss this exclusive video interview from AHR 2024! You can learn more about Copeland compressors at https://www.copeland.com/en-us/brands/copeland. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join hosts Bryan Orr and the HVAC School as they sit down with Chuck Allgood and Nick Strickland of Chemours at the 2024 AHR Expo in Chicago. In this video, Bryan interviews Chuck and Nick about Chemours' new lower global warming potential A2L refrigerants - Opteon XL40 (R-454A), Opteon XL41 (R-454B), and Opteon XL20 (R-454C). Nick provides an overview of the key features and benefits of Opteon's new "ABC" refrigerants - XL40, XL41, and XL20. He explains how the naming and order make them easy to remember, with R-454B (less than 750 GWP) as the current go-to for AC and heat pumps, R-454A (less than 300 GWP) for chillers, and R-454C (less than 150 GWP) for the California market. The discussion covers capacity, efficiency, real-world performance, and the shifting regulatory landscape driving the adoption of lower GWP solutions, leaving behind the Freon legacy. The guests also address common contractor concerns around handling, installation, and service of these mildly flammable A2L refrigerants, including line set routing. They point HVAC techs and companies to Chemours and other industry resources for training and additional information to help ease the transition. Learn more about the new Opteon A2L refrigerants at https://www.opteon.com/en/. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this 3D animation, Bryan Orr with HVAC School explains how to test a run capacitor properly while the HVAC system is under load. He covers the importance of capacitors for motor efficiency and reliability. This video provides a step-by-step process for testing capacitors under load using a multimeter to measure amperage and voltage. Bryan shares the formula to calculate microfarads and explains what capacitor readings indicate a need for replacement. This easy-to-follow tutorial is useful for both maintenance and service calls. Bryan emphasizes safety and meter accuracy as critical factors. He also mentions the free under-load capacitor testing calculator available in the HVAC School mobile app. Whether you're a beginner or a seasoned technician, this 3D video provides valuable tips for assessing capacitor performance. Check out HVAC School for more in-depth training! Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Bryan Orr continues his residential heat pump maintenance training for the Kalos team. In this lesson, he covers condenser coil cleaning, checking condenser components, indoor unit inspections, and more. Key topics include: Properly washing condenser coils with water or cleaner Inspecting condenser components like mufflers, accumulators, crankcase heaters, contactors Suction line and liquid line filter driers Compressor plugs and terminals Splitting condenser coils on clogged multi-row units Indoor observations - supply ducts, air leaks, evaporator cleaning Cleaning evaporator coils, including cleaning in place vs. pulling and cleaning Customer communication around needed repairs and upgrades Media filters Bryan emphasizes doing quality work without throwing others under the bus when previous maintenance procedures weren't done very well. He challenges the team not to get bored with maintenance procedures but to dive deeper and find ways to improve each system. The goal is to provide real value to customers while continuously honing their expertise. Residential Heat Pump Maintenance Part 1: https://youtu.be/hyJ-tT8M3Kc Tech tip about coil cleaners: https://hvacrschool.com/coil-cleaners-a-guide-to-which-cleaners-to-use-in-various-applications/ Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Symposium 2024 Is Coming! Roman Baugh talks a bit about the 5th Annual HVACR Training Symposium, especially the compressor teardown class... with a special appearance from Bert. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bryan Orr of HVAC School as he leads part 1 of a residential heat pump maintenance training session for the staff at Kalos. In this info-packed session, Bryan covers best practices and key topics, including: Reviewing equipment history and service notes Best practices for client communication Interacting with customers about system performance Conducting pre-checks and visual inspections Filter placement Common drain concerns Safely disconnecting power Properly accessing equipment Thorough cleaning procedures Bryan shares wisdom gained from years of experience while also encouraging participation and input from the Kalos team. This is an excellent class for anyone looking to improve their maintenance skills or bring new techs up to speed on proper service procedures. Stay tuned for more parts in this ongoing residential maintenance series. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Join Bryan Orr for this HVAC-focused 3D animated video breaking down everything you need to know about using a multimeter. In this Multimeter 101 for HVAC 3D animation, you'll get a back-to-basics overview covering fundamentals, safety precautions, tool selection, the megaohm scale, and measuring volts, ohms, amps, and microfarads. This animation contains detailed graphics clearly demonstrating how to take measurements in different units and scales, including best practices for testing the functions of your multimeter. Learn how auto-ranging works and why it matters. Understand key electrical principles that will help you accurately interpret your readings and perform diagnostic tests, including wiring the meter leads in series with the flame rod to read microamps on gas furnaces. Whether you're new to the trade or simply need a quick refresher, this Multimeter 101 video has you covered. Bryan explains core concepts in an easy-to-understand way, along with clear visuals of meters in use. Gain the confidence to safely use these essential diagnostic tools on HVAC equipment in the field. Take your electrical troubleshooting skills to the next level and set yourself up for success by mastering the multimeter. This is an HVAC training resource to help technicians build competency with metrics and tools that impact system performance and customer satisfaction. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this video, Bryan and Bert install the Sensi Touch 2 smart thermostat, covering some of its unique features along the way. You can learn more about the Sensi Touch 2 at https://hvacrschool.com/touch2. The #Sensi Touch 2 comes with some energy-saving features, including the auxiliary heat lockout, which allows the heat pump to operate on its own without the backup heat if it can handle the heating load. There is also a balance point feature, which locks out the heat pump when the heat pump is less efficient than the auxiliary heat. You can also connect the #Touch2 to Sensi room sensors (RS01-SG), which pull temperature data from specific points throughout the home. The Sensi Touch 2 design is also sleek and lightweight and provides an improved user experience. You can also add #contractor contact information to the thermostat so that customers can easily contact you whenever they need help; this feature is part of Sensi's contractor branding initiatives. The thermostat comes with two accessory terminals (ACC+ and ACC-), which allow you to connect supplementary equipment, like dehumidifiers, to be controlled by the smart thermostat. When Bert replaces the thermostat, he pays attention to the wire colors and terminals, though you can apply labels to the wires to help you install them correctly on the new thermostat. The Sensi Touch 2 comes with a leveling bubble, which allows you to mount the thermostat perfectly level on the wall. After reconnecting the wires to the new thermostat, use an insulating material to cover the hole in the wall, as the temperature conditions inside the wall will affect thermostat readings. Once the thermostat has been powered on, you can configure the settings on the screen. Occupants can easily adjust the temperature with simple plus and minus signs on the large display screen. They can also easily access operating modes and fan settings, allowing them to manage their comfort and #hvac system without hassle. Introducing Sensi Touch 2 - The Privacy-First Smart Thermostat: https://www.youtube.com/watch?v=ZclYr0LahAA Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

Instructor Bryan Orr dives deep into the nitty gritty details of compression ratio in HVAC systems in this HVAC School video. He touches on the answers to the following questions: What exactly is the compression ratio? Why does it matter? How is it calculated, and what impacts it? Bryan covers all of this and more using real-world troubleshooting stories and examples to reinforce key concepts. He examines compression ratio in different system types, from air conditioners to heat pumps to refrigeration. The class learns how condenser coil size, evaporator temperature, multi-staging, and even airflow affect ratio. Most importantly, Bryan shares tips for properly diagnosing and troubleshooting compression ratio problems in the field. What causes a low compression ratio? What are the consequences? How do you identify issues with the compressor, reversing valve, or metering device? The Kalos team gets crucial knowledge they can apply to every job. HVAC professionals at any experience level will benefit from the information in this video. Join the class and take your understanding of compression ratio to the next level! Preparing for Heating Season playlist: https://youtube.com/playlist?list=PLjmMtP2_3aVvR7uOrvp9rgm326vEg6BAT&si=HtRxwLB3os4GqPaU Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this HVAC training video, we show the process of diagnosing a locked compressor in a 3D animation. A "locked" compressor is what we commonly call a compressor that fails to start and goes off on overload. Topics covered include: The internal components of a compressor Refrigerant-cooled compressors What causes a compressor to lock up Operational overheating vs. overheated windings Diagnostic steps Thoroughly inspecting electrical components Checking voltage Verifying proper wiring Testing the run capacitor Using hard start kits to attempt to unlock compressors The operation of potential relays and start capacitors Soft start vs hard start compressor starting Even if adding a hard start gets the compressor running again, there may still be an underlying issue that initially caused it to lock up. Proper diagnosis and communication with the customer is key. This 3D animation provides HVAC technicians critical knowledge for troubleshooting locked compressors in the field. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this HVAC School video, instructor Bert continues his training for the Kalos team on preparing heat pumps for heating season. Picking up where Bryan Orr left off in part 1, Bert reviews auxiliary heat, heat strip wire and breaker sizing, and interlock relays. He then dives deeper into testing heat pumps when it's cold outside - checking charge, what to look for in terms of frost and ice buildup, abnormal signs, and more. Bert shares manufacturer charging charts, rules of thumb for pressures, and how to accurately check charge using a charging jacket. Additional topics include: Normal coil frost vs ice-bound coils Defrost cycle Cooling and heating cycles Reversing valve function Checking the charge in heat mode Accurately reading discharge temperatures Approach method Temperature split As always, Bert peppers the lesson with real-world stories and examples from the field to drive home key points. The video strikes a perfect balance between technical knowledge and practical application. Whether you're a seasoned pro or just getting started in HVAC, you'll learn valuable skills from one of the industry's most engaging teachers. Join Bert and the Kalos staff by watching "Heat Pumps - Preparing for Heating Season Part 2"! Part 1: https://youtu.be/t0Mz-Rxqvk8 Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this HVAC training video, Bryan Orr covers key topics to prepare the Kalos team for the heating season with a focus on heat pumps. He starts by discussing the common "burning smell" complaint when electric heat first turns on and stresses the importance of testing and burning off heat strips during maintenance. Bryan explains proper wire sizing, breakers, and connections for electric heat. He also covers blower interlock relay wiring to prevent heat from coming on without the blower. Additional topics include: Testing heat pump defrost Testing heat strips with an amp clamp Energy cost of heat strips Heat strip wire and breaker sizing (including Inspecting heat strips by pulling blower or strips) Undersizing issues Heat sequencers Heating season PM best practices The video provides a practical overview to ensure technicians are equipped with the basic knowledge needed for heat pumps and electric heat as we head into the heating season. Bryan stresses the importance of testing to avoid costly mistakes and emphasizes using resources like system checklists when in doubt. Video about wire sizing: https://hvacrschool.com/videos/how-many-amps-can-a-wire-carry-conductor-ampacity-basics/ Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this HVAC training video, Bryan Orr continues his class for the Kalos team to prepare them to work on gas appliances during the heating season. In Preparing for Heating Season Part 2, he dives deeper into different types of gas ignition systems like standing pilot, direct spark, intermittent spark, and hot surface ignition. Bryan explains how to properly adjust gas pressure on standard and Gemini gas valves. He covers safety considerations like checking for gas leaks, carbon monoxide, flame rollout, and improper venting. The video provides an overview of service sequence steps for gas appliances and other common service topics: Inspecting and cleaning burners Checking CO monitors Inspecting flame rods Checking venting and combustion air Measuring gas pressure Inspecting flames and displacement Measuring CO levels This is essential training for HVAC techs servicing gas appliances. Bryan provides real-world advice and safety tips to ensure technicians are prepared to handle heating systems this season. The video equips techs with the key knowledge needed for gas heating systems in Florida. Presentation: https://hvacrschool.com/heating-prep-furnaces Adjusting Gas Pressure on a Standard and Gemini Furnace Valve 3D video: https://www.youtube.com/watch?v=d1L6Ut2pIYI #BertLife - Gas Leak https://www.youtube.com/watch?v=bjmsez6q2uM&t=2s Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).

In this HVAC training video, Bryan Orr teaches a class to Kalos staff on preparing for heating season, focusing on gas appliances. This is part 1 of a video series preparing HVAC technicians for heating season service calls and maintenance. Most systems in Florida use 80% open combustion furnaces, which is different than other parts of the country that use 90%+ high-efficiency or condensing gas furnaces. The main tools we use with gas appliances include a combustible gas leak detector (to find leaks), combustion analyzer (to test the flue gases for commissioning), manometer (to adjust gas pressure at the gas valve, also used to measure static pressure), and low-level CO monitor (for personal safety). Since we typically have metal flues in our market, drilling a hole into the flue for combustion analysis is difficult; we may alternatively stick the probe into the outlet of the flue. Low-level CO monitors measure ambient carbon monoxide levels (NOT carbon dioxide / CO2) to protect HVAC professionals when they work. The top skills you will need to work on gas appliances are carrying out a thorough visual inspection, examining the surrounding areas (not just a furnace), using a manometer to measure gas pressure (on either a standard or Gemini gas valve), using and selling low-level CO monitors, and using a combustible gas leak detector to find gas leaks. The gas furnace sequence of operation begins with a W call from the thermostat, which prompts the board to confirm that the pressure switch is open. If the pressure switch is closed, the inducer fan will start, which leads to the pressure switch closing. The board will confirm that the safety circuit is closed, which is an ongoing process, before the ignition sequence begins. The gas valve then opens to allow natural gas to come through, and then a flame should propagate. From there, the flame rod (or flame rectifier) will prove the flame. (The furnace must be well grounded, and the rod must be clean and immersed in flame.) The blower turns on as the final step in the sequence of operation. Topics covered in this video include: Uses of tools like combustion analyzers, personal CO monitors, and gas leak detectors Caps and leaking gas lines Common issues to look out for, including gas line leaks, corrosion, improper burner alignment, improper combustion air, etc. The importance of thorough visual inspections on gas appliances Some gas pool heater practices Practical skills like setting gas pressure, checking for ambient CO, and leak testing An in-depth look at each step of the gas furnace sequence of operation Silicon carbide vs. silicon nitride ignitors (for HSI modules) Flame rectification Signs of problems like scorching or heat damage What really causes back drafting and CO spillage Above all, it is important to be attentive to potential safety issues, protect the client, and use opportunities to suggest upgrades that keep the customer safe. Adjusting Gas Pressure on a Standard and Gemini Furnace Valve 3D video: https://www.youtube.com/watch?v=d1L6Ut2pIYI Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This 3D video will show the process of diagnosing a grounded compressor in a split residential HVAC system using isolation diagnosis. We may also call these compressors “shorted to ground.” When you find a tripped breaker, avoid resetting it; it may be tempting to reset the breaker and see what happens, but the breaker is tripped for a reason; closing the circuit again may cause the overcurrent condition to create a major arc or spark. Shorts at the compressor may also cause carbon and acid to enter the refrigerant and contaminate the system. Our diagnosis should start off with a solid visual inspection of high-voltage wires, terminals, contactor, capacitor, crankcase heater, breaker, and disconnect. At this time, we must take extra care to note wire rubouts or abrasions, signs of arcing, and loose connections. Then, we’ll inspect the compressor leads and terminals, wearing appropriate PPE. Before removing the compressor wiring, take a picture of the terminals so that you can remember how the compressor was wired when it’s time to put it all back together. With the wires pulled off, you can measure the resistance to ground at each terminal with a megohmmeter, using the suction or discharge line as your ground. The quality of the reading will depend on the quality of the meter you use. Low resistance values indicate a short, though a short may also be present even if your resistance values are within the acceptable range. Abrasions and black stains on the windings are also signs of a short. However, stains may also contain enough carbon to insulate the shorted area, causing a regular resistance reading. When high voltage is applied, the low resistance will show up when reading in the megohm scale. If you have evidence that the compressor is shorted to ground, you can isolate the compressor by taping or plugging the terminals so that they don’t touch anything. Then, you can reassemble the unit and run it without the compressor. If the breaker doesn’t trip, and everything runs correctly, you can be sure that the compressor is grounded. If the breaker still trips, then you can confirm that a grounded compressor is not the issue. Buy your virtual tickets or learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/symposium24. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

We look at the unique features of the 50E47U-843 Universal Hot Surface Ignition Module for #hvac and more by Copeland White-Rodgers. For more information about this product, visit https://hvacrschool.com/hsimodule. Similar to the other versatile White-Rodgers #universalcontrols, the 50E47U-843 replaces 325+ part modules for HSI modules, whether you're working with 24v, 120v, or 240v ignitors. You can use this universal HSI module in all sorts of gas-fired #heating appliances, including #hvacr equipment, pool heaters, boilers, and laundry equipment. It controls and receives inputs from all required components, including inducer fan motors, flame rods, pressure switches, and ignitors, with an easy-to-install harness. You can transfer your old wiring connections before removing your old module. Along with some of the other White-Rodgers universal furnace controls, you can program and diagnose the 50E47U-843 offline #furnacecontrol (and without having power to the module!) using the White-Rodgers Connect App, which uses NFC technology. You can select from several preloaded OEM settings in-app to program the module before installation. This module also displays the real-time flame current (DC microamps), which will give you an idea of how the flame rod and board are working together during diagnosis. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this 3D video, we show how to calculate heat losses and heat gains in a residential structure in accordance with ACCA Manual J, particularly a block load for an existing structure. We owe special thanks to Russ King, Ed Janowiak, Alex Meaney, and Adam Mufich for their contributions to this video. Heat and Comfort Basics 3D: https://www.youtube.com/watch?v=zVEkVL36Ni4&ab_channel=HVACSchool HVAC School Manual J Block Load Worksheet: https://hvacrschool.com/wp-content/uploads/2023/08/Block-Load-Worksheet.pdf Kwik Model 3D: https://kwikmodel.com/ Air Conditioning Contractors of America (ACCA): https://www.acca.org/home Load calculations require us to use math, and we can use Manual J software to do that work for us. However, we still need to obtain the data for the math in the first place; Manual J tells us which measurements we need to enter into the software for the load calculation. We can use Manual J to figure out block loads of an entire building or room-by-room calculations. Manual J may also be used in existing buildings or based on the plans of a new construction. When gathering data from walls, we need to know the area and the R-values of each material making up the wall, including drywall, insulation, and exterior building material. Higher R-values indicate better resistance to conduction; we can control the material thickness and insulation to minimize heat conduction into or out of a structure. You’ll need to deduct the studs, windows, and doors from the R-value of a wall. Partition walls between other indoor spaces, like a neighbor’s home or an unconditioned garage, have different temperature differences (delta T) than an exterior wall. To deduct the window area from the wall area, you’ll need to multiply the length and width of the wall and the length and width of the window(s) and subtract the product(s) of the window area from the wall area. The window will have its own calculated heat losses and gains due to its ability to allow for heat transfer via radiation. Heat gains via solar radiation will vary depending on the window placement and the time of day. We need to know the window size, material, framing, transparency number of panes, and placement of the windows to understand the U-factor, which is the inverse of the R-value; higher U-factors indicate higher rates of heat transfer. Roof overhangs can reduce incoming solar radiation, so we need to account for the height and depth of roof overhangs in our calculations. We should also know the roof type, pitch, and color. When accounting for exterior doors, we need to know the door size, material, and placement. We also need to know the elevation of the home and how many stories it is. The ceiling height and insulation (material and R-value) are also important for our Manual J calculations. Conduction also happens through the floors, so we must know about the material and possibly even the R-value of insulation (if applicable). When considering the impact of ductwork on heat gains and losses, we need to factor in duct location, insulation R-value (often R4, R6, or R8), and leakage (due to heat gains and losses via convection into or out of the ductwork). We also need to know if the air handler is in a conditioned or unconditioned space and how exhaust-only ventilation may be responsible for seasonal BTU gains and losses. Household appliances add heat, and Manual J has a default appliance heat load of 1200 BTUs. Electronics also add sensible BTUs, and dishwashers or laundry appliances may also add latent BTUs. We can also expect higher latent BTU gains in homes where occupants frequently run faucets, do laundry, or bathe/shower. Occupants add heat loads when they breathe or their bodies give off heat, usually about 200 latent BTUs per hour and 230 sensible BTUs per hour. Account for occupants by adding up the number of bedrooms and adding one (e.g., we would calculate a heat load for four occupants in a three-bedroom home). Appliances will not run all the time, and heat loads based on weather will vary throughout the year (and even throughout each day). There may also be more or fewer occupants than the load calculation accounts for at any given time, so we want to design homes to account for the most probable and common conditions, including the occupants’ lifestyle choices (see Table 6A). Once we have the data, we can finalize our load calculations with ACCA-approved Manual J software, like Kwik Model 3D as shown. You can also use HVAC School’s Manual J worksheet. Then, we can move on to equipment selection in accordance with ACCA Manual S. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

During 4th Annual HVACR Training Symposium Jim Bergmann and Chris Hughes teamed up to give their humorously titled session, “HVAC Commissioning on Steroids Without the Pimples.” They talked quite a bit about commissioning tools like measureQuick and Trueflow and showed how someone could use it to test for return duct leakage. Return duct leakage can significantly reduce system capacity and efficiency, and you can estimate it using two mixed air probes and measureQuick. Once you perform the test correctly, measureQuick will display the data picked up by your test instruments and estimate the leakage and capacity loss. By watching their full session, you can learn how to do that test and add some more game-changing commissioning strategies to your toolbox. Jim and Chris also covered: Impact of leaky ductwork How to sell the value of the work you do - with confidence Using commissioning to catch issues Workflow and Illustration of Workflow and Diagnostic Test Methods ( ANSI / RESNET / ACCA / ICC 310-2020 ) Equipment Capacity vs. Delivered Capacity mQ Vitals Score Pricing HVAC projects Finding gross revenue target Measuring airflow Steve Rodgers and Bill Graber class on Supply Duct Leakage from 3rd Annual HVACR Training Symposium: https://www.youtube.com/watch?v=03QDvytGjSE Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Matthew Taylor teaches the Kalos commercial HVAC/R professionals about Vacuum Practices for Large Jobs and does an evacuation demonstration (including pulling a vacuum on a water-filled pipe). This video is the final in our series on commercial HVAC/R pipefitting. After performing a nitrogen pressure test, you'll vent the nitrogen and prepare for your evacuation (deep vacuum). A vacuum pump creates an area of low pressure relative to the atmosphere; since molecules move from areas of higher pressure to lower pressure, unwanted air and water molecules will move out of the system and into the vacuum pump. Liquid water also boils off during evacuation. We use a very tiny unit of measure for evacuation, the micron (one-millionth of a meter of mercury column), and we need a gauge that can read microns. You should use a vacuum pump that can pull a vacuum as low as 50 microns when isolated from the system (micron gauge fastened to the pump). The pump should be sealed during storage to prevent oil contamination, and then you should use large-diameter hoses (more than 1/4") when pulling a vacuum. When you're dealing with a wet system, you can leave the gas ballast open to keep moisture from condensing in the vacuum pump oil. Using the gas ballast will cause smoke to leave the pump, which could fill the room and cause you to drain oil; it is also far less efficient to run with the gas ballast open for the full length of every evacuation. The vacuum pump oil should be clean and at the proper level for EVERY evacuation, and you may have to change the oil several times during a large market-refrigeration evacuation job. You can check the sight glass to see your oil level and cleanliness. If the level is low or the oil appears milky, you should drain out the old oil and replace it with clean oil. To pull a deep vacuum as deeply as possible, use a core removal tool with large hoses (not a manifold) and remove Schrader cores. To get the most accurate measure of your vacuum, connect your micron gauge as far away from the pump as possible. Then, you'll want to pull a vacuum below the manufacturer's recommended pressure (often 500 microns, but it can be as low as 200 microns for new systems). Once you've pulled a deep vacuum, valve off the pump and perform the decay test. The decay test will let you know if your system is clean, dry, and tight, and it can last anywhere from 24 hours to 30 days on large commercial HVAC/R equipment. During the decay test, the vacuum shouldn't "decay" past a certain threshold (usually 500 microns for new systems and 1000 for repairs on commercial HVAC/R equipment, though the threshold will vary by application). When you pull a deep vacuum, you will experience very quick gains at the beginning of the evacuation, and you will pull down a lot more slowly when you get closer to the target. You may have to valve off the vacuum and let the system stabilize before pulling down again, which is a best practice that descended from triple evacuation (we're just not breaking the vacuum with refrigerant or nitrogen). After valving off the vacuum pump, we can monitor the decay on apps like measureQuick. Once a system passes the vacuum test, you can charge it with refrigerant. Find another part of this class with Matthew Taylor on Pressure Testing Large Jobs here: https://www.youtube.com/watch?v=9VqlhaUQz5A&t=4s Buy your virtual tickets or learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Matthew Taylor gives a short presentation and performs a demonstration about nitrogen pressure testing for large jobs (commercial HVAC and refrigeration). Pressure testing with nitrogen will help you ensure that there are no leaks in systems with up to several hundred feet of tubing. Nitrogen is ideal for pressure testing because it's inexpensive, and its pressure doesn't respond significantly to changes in temperature. You can easily fill the entire system with nitrogen and determine if you have leaks in places you can't reach with a leak detector. You do NOT want to pressure-test a live system with refrigerant in it; you'll have to isolate the part you want to pressure-test. Before pressure testing, think through your application; you'll want to know if you have a new store, a new line set, new cases, or an active rack. Each one will require a unique approach. When starting the test, you'll want to make sure you have a gauge that you can leave attached to the system for a long time, sometimes upwards of 30 days for new systems; analog gauges are sometimes preferable for that reason, and they don't need to be perfectly calibrated as long as you can see that the pressure is maintained. The original pressure should be documented so that you will know how much the system has leaked when you return to it. When you pressurize the system, set the nitrogen regulator to the maximum test pressure as recommended by the manufacturer and apply a leak reactant (bubble solution) to the joints to check for bubbles and microfoam, both of which indicate leaks. When you've finished the test, you can release the nitrogen and either address the leaks and redo the pressure test or proceed with evacuation. Buy your virtual tickets or learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Nathan Orr and Roman Baugh teach a segment of the Kalos pipefitting class, focusing on the importance of purging and flowing nitrogen during the brazing process. They also focus on torch use. This video is the second in a short series about pipefitting practices for commercial HVAC/R. Purging and flowing nitrogen while brazing displace oxygen and keep it out of the copper tubing, preventing the formation of cupric oxide inside the tubing. However, if left uncapped or unsealed, the tubing may be contaminated before brazing, and we should do a visual inspection to check for foreign objects or contamination. To reduce the risk of contaminating the copper tubing with shavings, we should clean the copper before we cut it, use a proper tubing cutter, and be careful not to let the burr or shavings fall in after deburring. Failure to deburr or ream the copper can cause turbulent flow in the lines, leading to possible vibration leaks. Complacency during the tubing preparation process often leads to errors. When it’s time to insert the tubing, the depth of the fitting should be equal to the tubing diameter. There should also be very little space between the tubing surfaces; wide gaps between surfaces lead to poor penetration due to insufficient capillary action. We purge systems with nitrogen to displace oxygen inside the tubing before brazing; purging requires a higher SCFH output than flowing. After purging, we flow the nitrogen at a much lower SCFH output to keep oxygen from going back into the tubing, and we keep flowing during the actual brazing process. Note that flowing nitrogen is NOT the same as pressurizing with nitrogen, and we’ll want to keep from sending nitrogen through live refrigerant circuits and components (like valves, compressors, etc.). If we don’t purge the system and flow nitrogen while brazing, we’ll get black scale buildup, which can be mistaken for burning the pipe at first glance; heating the joint doesn’t cause black scale (cupric oxide) buildup; brazing without flowing nitrogen does. Brazing often happens near heat-sensitive components, including valves. We must protect those with heat-blocking putty and wet rags to avoid damaging them. When working with valves with sensitive seals or gaskets, we should ensure that those are in the mid-seated position before we start brazing. The main two factors that will dictate torch selection are piping diameter and application (i.e., accessibility and clearances). Some torch tips are designed to help apply heat evenly in tight spaces, like the Cap’n Hook tip. Rosebud tips are ideal for applying heat over a relatively large area. Torch tips that are too small cannot adequately heat a joint and can lead to leaks in the future, and tips that are too big expend oxygen and acetylene too quickly. When we set oxygen and acetylene pressures, we have to make sure the regulators are shut off and that you know which gauges are for your tanks and which ones are for your hoses. Bubble test the connections and hoses for leaks, and be sure to set the tank pressures at the regulator instead of the handle. Flames come in three varieties: carburizing, neutral, and oxidizing. Carburizing flames have excess acetylene and have large secondary feathers; these can cause chemical reactions on the surface of the base metal, so we want to avoid using these flames. The neutral flame, which has an even mix of oxygen and acetylene, is the most desirable flame we can have. Oxidizing flames have too much oxygen, have a small cone, and lack a secondary feather; these flames can cause cupric oxide to build up inside the joint. The ideal brazing technique is to start by brazing the joint closest to the nitrogen source. To begin heating the joint, start by applying the torch to the male end of the connection and then gradually apply heat to the whole joint. The torch doesn’t melt the alloy, as it doesn’t enable the alloy to draw deep into the joint; instead, the base metal should be hot enough to melt the alloy. When copper is hot enough to melt the alloy, it turns a cherry red color. While you’re heating the joint, move the torch slightly to keep the heat evenly distributed, but try not to move the torch too much; otherwise, the joint might not heat up properly. Some common problems pop up when we’re dealing with joints that are too hot, joints that are too cold, or tubing gaps that are too wide. Proper tubing preparation and torch use will help you avoid these problems and their consequences, including leaks and pipe damage. Buy your virtual tickets or learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This video is a Kalos Services training class about basic Brazing Techniques. The class was primarily aimed at commercial pipefitters and is the first in a series of classes. The words "brazing" and "soldering" are sometimes used interchangeably, but soldering really occurs at temperatures below 840 degrees Fahrenheit, and brazing occurs at temperatures above 840 degrees. We may end up brazing or soldering when joining or repairing metal tubing; to join metal tubing, we need to heat the base material to the point where it's hot enough to melt a brazing alloy and draw it into the joint via capillary action. Some technicians are afraid to burn through the pipe and end up not heating the joint enough to draw the alloy in, especially if they mistake cupric oxide formation for a burnt pipe. Repairing requires us to create strong bonds over leaks by patching them and requires a different technique from joining. Copper-to-copper brazing is one of the most common and straightforward pipefitting tasks, as it uses a phosphorus-based alloy and does not require a separate flux. You cannot use phosphorus-bearing rods when brazing or soldering copper with dissimilar metals, as different base metals have different properties. Each metal will have different compatible alloys and fluxes, conductivity, and melting points. Copper has high thermal conductivity (relative to other metals) and a melting point of around 1950 degrees Fahrenheit. Alloys are filler metals, and we want to pick ones that are appropriate for the base metal(s) and as ductile as possible; alloys with higher silver content tend to be more ductile than ones with lower silver content. Flux helps the alloy flow and also keeps oxides from forming on the base metal. Oxides form on the base metal when oxygen combines with the base metal; in copper, temperatures above 900 degrees allow oxygen to combine with copper and form a black scaly substance called cupric oxide. These oxides make it difficult to create a good joint, and oxides inside the tubing can come off the tubing with POE oil, which makes the oxides clog filters and screens. Along with using an appropriate flux, purging the system with nitrogen before brazing and flowing nitrogen while brazing are the best practices to prevent oxides from forming in the tubing. Nitrogen displaces oxygen before brazing and keeps it out while you're brazing. To be safe while brazing and soldering, we need to keep a fire extinguisher handy at all times, keep the work area clean, and wear proper PPE (including safety glasses of an appropriate shade). Oiling regulator threads can also increase the risk of combustion, and it should never be done. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this 3D video, we look at the causes and effects of freezing in HVAC systems (buildup of frost or ice on the equipment). Water freezes at 32°F or 0°F. When a surface, such as an evaporator coil, is below water’s freezing point and contains moisture, frost or ice may form on that surface. In many cases, freezing in HVAC systems starts at the evaporator coil and works its way out; freezing can happen when the suction saturation temperature stays below 32°F for an extended period of time. Some HVAC/R applications, such as commercial freezers and heat pumps in heating mode, need to operate under below-freezing conditions; the formation of frost or ice will hinder heat transfer over time, and periodic defrosting will be required. Evaporator coils in cooling mode should NOT freeze; when freezing happens, it will block system airflow. In general, evaporator coils will be about 35°F below the return air temperature. The rate at which freezing occurs will depend on the amount of moisture in the air, the length of time at which the evaporator coil temperature is below freezing, the temperature of the return air, the air velocity, and the overall coil design. When you encounter a frozen system, allow it to defrost completely before troubleshooting. You may allow the system to defrost by leaving it off with (or sometimes without) the blower running. In some cases, you may be able to use a heat gun or run the heat pump in heating mode for a short period. Be mindful of the water as the ice melts and take steps to prevent water damage. A low evaporator coil temperature may be caused by low load (low airflow and/or low indoor temperature), refrigerant undercharge, low outdoor ambient temperatures, blower issues, and refrigerant side restrictions. We can prevent low load by advising customers not to set their thermostats below 72°F in cooling mode on standard equipment. We can also prevent low airflow from being a factor by making sure we replace dirty filters and clean the evaporator coil and blower wheels as necessary. When freezing happens due to a low refrigerant charge or a restriction, we may also notice high superheat; in humid climates, freezing of this nature can cause the entire system to freeze up. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This video is David Richardson’s presentation from the 4th Annual HVACR Training Symposium: “How to Confidently Create a Duct Renovation Scope of Work.” He explains how to create a duct renovation scope of work and incorporate them into your company services. Residential air balancing is largely a development of National Comfort Institute’s (NCI’s) late, great Rob Falke, and it was a major step forward for performance-based HVAC system design. Nowadays, we can think of HVAC systems as puzzles with four large pieces and several smaller ones each; the four broad categories are design, installation, verification, and communication. HVAC professionals bring life to the system during the installation; incorrect installations lead to premature system failure. Duct renovation is not easy work, but it is a profitable upgrade for homeowners. Older duct renovation practices started and ended with repairs, but we can give customers much better HVAC systems by following a detailed process of testing, diagnosing, and prescribing a solution before repairing. During the starting phase, perfectionism is a common obstacle for many technicians who worry about missing their airflow targets; we need to prioritize progress over perfection. Other obstacles include customers that are unwilling to purchase duct renovations, expensive tools, and the labor shortage. Scheduling can mitigate some of these, as seasonal price fluctuations (lower in shoulder seasons and winter) and lighter winter schedules can make duct renovation more attractive for your company and the customer. There are two duct renovation approaches: air upgrades and duct optimization. Typical air upgrade features at the equipment include reducing static pressure drop across the filter, improving duct fittings, system cleaning, adjusting fan speed, and charging/recovering refrigerant. Air upgrades in the ductwork include adding one oversized return duct and grille into a large area, using 8” ducts with balancing dampers, sealing leaky ductwork, supporting the ducts with proper strapping, replacing restrictive fittings, and upgrading the grilles and registers. Duct optimization requires us to customize an existing duct system so that it can deliver individual rooms’ BTU targets, often including the installation of balancing dampers and grille and register upgrades. Testing is the starting point for a duct renovation. You can get a solid start by performing airflow tests. Thermal imaging cameras are also useful tools to look for signs of building envelope leakage that needs to be addressed. The five basic rules for duct renovation are (1) don’t renovate ducts on oversized equipment, (2) involve the customer in the process, (3) focus on one thing, (4) get paid for the time and effort you put into your designs, and (5) use all the puzzle pieces (i.e., go through all of the testing and steps required to produce a duct renovation scope of work). As with the basic rules, there are five questions to ask about any duct renovation: (1) Why are you there? (2) What are you trying to accomplish? (3) What does the customer want you to solve? What is their pain? (4) What access do you have? (5) How many people need to be involved in the renovation (for communication purposes)? For best results, make sure you know your customers’ goals and let them make decisions. You’ll also need to make sure information is communicated effectively between salespeople and installers (and anyone else who is involved in a duct renovation). As you serve your customers, you may have to renovate some systems you installed due to improvements in technology and our understanding of HVAC design over time; duct renovations on systems you designed should not be free. David presents seven steps for a duct renovation: (1) perform a visual inspection of the entire system and the building, (2) measure the system to identify duct inefficiencies, (3) diagnose your readings, (4) conduct an interview with your customer, (5) communicate the scope of work to the customer and your team, (6) perform the duct renovation, and (7) test out and generate an assurance report. A visual inspection gives you the opportunity to find issues in plain sight that you’ll want to address. After your visual inspection, start taking readings of the HVAC system’s “vital signs,” including total external static pressure, component pressures (coil and filter pressure drops), duct pressures, fan airflow, and system airflow. You will use those readings to diagnose the problem. . Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this 3D video, we show the differences between ACFM vs SCFM, also known as actual cubic feet per minute and standard cubic feet per minute, respectively. Both are means of quantifying airflow, but they show the difference between mass flow rate and volume flow rate. CFM represents cubic feet per minute, which can represent a 1’ x 1’ x 1’ box of air. The blower moves hundreds of these boxes per minute. That air may have varying temperature or humidity levels. The standard CFM (SCFM) conditions consist of air at 68.3 degrees Fahrenheit and 0% humidity at atmospheric pressure. A cubic foot of air will weigh 0.075 pounds under these conditions, but this weight will change when there are changes in temperature, pressure, and humidity. HVAC systems also move several boxes of air, with each one exerting force on the others. The air we breathe primarily consists of nitrogen (78%) and oxygen (21%), plus some trace substances. These molecules move faster when we apply heat, making them more spaced out and less dense, which reduces the weight of a cubic foot of air. Water vapor (humidity) weighs less than diatomic nitrogen and oxygen in the atmosphere, so higher humidity levels will reduce the weight of a cubic foot of air. Lower pressures, such as at high elevations, will make the air less dense, which will also decrease the weight of a cubic foot of air. For those reasons, the 400 CFM per ton rule of thumb is not applicable to all climates. We want to focus on maintaining a fixed mass flow rate, which accounts for the weight of each cubic foot of air. ACFM accounts for the weight of the air we’re moving to account for variations in humidity, altitude (pressure), and temperature. Arid climates are likely to have higher target ACFM rates, and humid climates are likely to have lower target ACFM rates. SCFM is a common reference point during the commissioning and testing of equipment, and ACFM is more likely to give us a nuanced idea of the pounds of air our systems are moving. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This video is of Joseph C Henderson’s presentation at the 4th Annual HVACR Symposium: Air Flow Diagnostics. Recently, the industry updated its testing standards (SEER2, EER2, etc.) to account for the static pressure of ductwork; previous testing protocols didn’t consider the effects of static pressure in the ducts. ACCA Manual D is the industry standard of duct design, and Manual Zr deals with zoning (which depends on the integrity of the ductwork). Systems designed with Manual D tend to have better performance and airflow than systems that aren’t designed with Manual D in mind. When measuring and optimizing airflow, we can only expect better results if we use the proper test instrumentation, not just the “handometer.” In the ductwork, we have two main sources of pressure: velocity pressure and static pressure. Air is always trying to expand, so static pressure is exerted on the surfaces of the duct and creates resistance because ducts can’t expand. When the static pressure is too high, the blower motor can perform poorly and even fail prematurely. We want just enough static pressure to ensure that we have a solid throw of supply air and smooth, quiet return air. We can measure static pressure with manometers. Manometers measure pressure differentials, and we can use them with static pressure tips (pointed into the flow stream) to measure static pressure. A static pressure tip does not have a hole in it and is NOT the same thing as a pitot tube. Alternatively, you can insert a straight piece of tubing into the duct and point at a 45-degree angle WITH the airflow. You want to account for all sources of resistance when measuring static pressure, so you’ll want to account for the filter and the coil. The airflow should be straight, also known as laminar airflow. You will need 3–5 feet of straight duct to ensure that you achieve that laminar flow. You can also see how the motor is doing by taking an amp draw reading. Lower amp draws indicate that a PSC motor isn’t moving the full amount of air. Full load amps will indicate that the full amount of air is being moved, but it will not tell you if the static pressure is balanced. (Ideally, the return static should be lower than the supply static.) Variable-speed and X13 motors tend to be more efficient, but their airflow capabilities are similar to PSC motors, and they still have their static pressure limitations. Constant-torque motors will have a slight increase in amp draw before dropping. Constant-CFM motors will pull far more amps than X13 and PSC motors. PSC and X13 motors may only deliver air up to 0.5” of external static pressure, so you’ll want to make sure you start off with a maximum of 0.3” (0.1” on the return and 0.2” on the supply) so that the blower can handle additional resistance from coils and filters as they get dirty. Constant-CFM motors may maintain their set airflow up to 0.8”–1” of static pressure, and you can typically start off with 0.35”–0.5” of static pressure; when the motor has to ramp up too much to maintain a constant CFM, the efficiency takes a hit. Constant-CFM motors are appealing because they tend to be quiet and efficient, but they can get louder and more inefficient under higher static pressure conditions. To keep the static pressure down in the ductwork, you’ll want to make the trunk line as straight as possible. You’ll also want to keep flex ducts straight and tight to prevent compression, which adds resistance. Mitering the inside turns is also best practice to cut static restrictions (unless you have turning vanes). Be mindful of duct fittings, as they can significantly affect the static pressure restrictions. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Jason Obrzut, Don Gillis, and Dr. Chuck Allgood give a flammable refrigerant update at the 2023 HVACR Training Symposium. They talk about the latest news regarding regulatory updates and the transition to low-GWP A2L refrigerants. The AIM Act mandates the phasedown of high-GWP HFCs federally (state regulations may vary a little bit, but all of them will have an HFC phasedown); in the end, production will be decreased by 85%, meaning that there is not a total refrigerant phaseout. Recovery and reclamation will be crucial. R-32, an A2L refrigerant, has been used in window and package units, and R-1234yf has also been used industrially and in automobiles. Most A2Ls going to market will include those refrigerants and refrigerant blends. Installation and design standards will be tailored to the A2L refrigerants. A2Ls are nowhere near flammable as A3s, including propane. ASHRAE Standard 34 establishes a lettering and numbering system based on toxicity (A or B) and flammability (1, 2L, 2, and 3). Non-toxic refrigerants have the letter A, and toxic ones have the letter B. Non-flammable refrigerants under test conditions receive the number 1, mildly flammable receive 2L, moderately flammable receive 2, and highly flammable refrigerants receive 3. We have largely been working with A1 refrigerants, like R-22 and R-410A. A2Ls are non-toxic but propagate a small flame under test conditions; A2Ls are significantly less flammable than A3s, like hydrocarbons, which is evident in Dr. Chuck’s flask test. Flammability also depends on properties like the minimum ignition energy, the heat of combustion, and the burning velocity. A2Ls take a lot more energy to ignite than A3s, and their heat of combustion and burning velocity values are quite low by comparison. The industry is moving to A2Ls to minimize risk (as opposed to A3s). Systems for A3 refrigerants typically have smaller charges than other systems with lower flammability to minimize risk. We will start seeing new tanks with special safety features, including ones with spring-loaded pressure relief valves that can open and close automatically if the pressure gets too high. You’ll likely see left-handed threads on some tanks, and adapters may become available for them. Recovery tanks will also have a red stripe, and you can decommission tanks by puncturing them (not with a ruptured disc). Refrigerant tanks will come in neutral colors and have shrink wrap to prevent counterfeit refrigerant from entering circulation, and the refrigerant name will be labeled on the tank. Some of the best (albeit not required) practices for A1s will be required for A2Ls. These include purging the system with nitrogen, evacuation, and leak/pressure testing. Otherwise, the refrigerants have very similar pressures to R-410A, and working on systems with A2L systems will be similar to working on R-410A systems. You can email questions to Don at [email protected]. You may also check out Opteon’s website at https://www.opteon.com/en, AHRI’s Safe Refrigerant Transition Task Force at https://www.ahrinet.org/advocacy/safe-refrigerant-transition-task-force, and educational resources on ESCO Group’s HVACR Learning Network at https://hvacr.elearn.network/. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bert teaches a class about failed compressors and what you should do when you encounter one; he also explains why you don't want to "just replace it." Acid can kill a compressor, and it is one of the most common causes of compressor death after replacement. Moisture contamination in the system mixes with POE oil to form acid, which degrades the oil's ability to lubricate the compressor and leads to premature failure. High heat and electrical burnout may also cause acid formation in the system. When you diagnose a compressor, you will want to follow an extensive diagnostic process, not just replace it. A thorough diagnosis will help you figure out if the system has acid. Some common signs of acid in the system include positive results on an acid test kit and a pungent odor when you remove your hoses. When addressing an acid problem, you will want to replace the compressor AND accumulator, do an acid flush or other form of acid treatment, and install a suction line filter drier (being mindful of the one-way flow and appropriate installation practices). You can either remove the contaminated line drier after 10-14 days or replace it with a fresh one after 10-14 days. Be mindful of system and condenser airflow when you diagnose a compressor; watch for inappropriate or multiple filters, damaged or improper ductwork, inappropriate blower settings, a dirty or clogged evaporator coil, a dirty blower wheel, or a dirty and impacted condenser. Poor airflow can cause high temperatures and pressures, which strain the compressor. Airflow issues at the evaporator can also prevent refrigerant from fully boiling off, which can lead to liquid going into the compressor and causing premature failure. It is important that you quote for these issues so that customers can make educated decisions. You'll also want to be mindful of the refrigerant charge and how it may contribute to early compressor failure. Low refrigerant charge can cause the superheat to be higher than usual; coupled with longer runtimes, a low refrigerant charge can be a problem when we're dealing with refrigerant-cooled compressors. We can use a P-T chart, do a standing pressure test, or weigh out the refrigerant to check for a low refrigerant charge. Leak detection can help you find a leak, which is a common cause of low refrigerant charge. It's also a good idea to be prepared to complete a full test after installing and starting up the new compressor. Electronic issues may also be involved in compressor failure. Failed capacitors, especially on hard start kits, can cause the system not to run; you will want to make sure that you have tested all of those accessories. If a compressor has a factory hard start kit, you will want to replace the hard start kit with the compressor; an aftermarket hard start kit may just need to be removed, not replaced. Pitted contactors, switch problems, poor connections, and wire damage can also cause the compressor to run continuously or short-cycle the compressor, both of which lead to early compressor failure. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Eugene Silberstein teaches his class based on his book, "Pressure Enthalpy Without Tears," at the 2023 HVACR Training Symposium at the Kalos HQ in Clermont, FL. Eugene is the Director of Technical Education and Standards at ESCO and is a current co-author of the RACT manual. Many people are intimidated upon their first exposure to pressure enthalpy, and there are barriers to understanding that prevent us from troubleshooting systems. It's helpful to think of a pressure enthalpy diagram as a picture that represents an entire system and provides value to technicians. When you plot a pressure enthalpy diagram, you can get an idea as to whether a system is functioning as efficiently as designed. A pressure enthalpy chart can tell you about the system's net refrigeration effect (NRE), total heat of rejection (THOR), heat of compression (HOC), coefficient of performance (COP), mass flow rate per ton (MFR/ton), system mass flow rate (MFR), compression ratio, theoretical horsepower per ton (THP/ton), Energy Efficiency Ratio (EER & EER2), Seasonal Energy Efficiency Ratio (SEER & SEER2), evaporator and condenser capacity (in BTUs/hour), and compressor volumetric efficiency (in CFM). To plot a system on a pressure enthalpy chart, you need to know the high-side pressure, low-side pressure, condenser outlet temperature, evaporator outlet temperature, and compressor inlet temperature. You're already picking up many of these readings when you measure superheat and subcooling, which you already do during a typical service or maintenance procedure. The vertical axis of a pressure enthalpy chart shows the pressure (in PSIA, not PSIG); therefore, horizontal lines represent constant pressure. If you are using gauge pressure, you will need to add 14.7 to your numbers to get the PSIA. The horizontal axis represents enthalpy, and the vertical lines on a pressure enthalpy chart represent constant enthalpy; enthalpy is a measure of the total heat content. The saturation curve or "thumbprint curve" on the pressure enthalpy chart represents the values on your P-T chart; the refrigerant in that range is a mix of liquid and vapor; anything to the left of the curve represents subcooled liquid, and anything to the right is superheated vapor. If a point is closer to the left edge of the saturation curve, it is mostly liquid but still a liquid-vapor mixture; points closer to the right edge of the curve are mostly vapor but are still at saturation. To the right of the curve, the lines that bend toward the x-axis outside of the saturation curve represent lines of constant temperature; other curved lines that trend slightly upward are lines of constant volume, and the more steeply upward-curved lines represent lines of constant entropy. A completed chart contains a parallelogram that represents the system. The compressor is represented by a diagonal line (of constant entropy) trending up and to the right. Typically, a horizontal line on top will represent the condenser, and a horizontal line on the bottom will represent the evaporator. A vertical line connecting the horizontal lines typically represents the metering device; the heat content stays the same, but the pressure and temperature change. The position of the parallelogram will indicate potential problems with the refrigerant charge. (Overcharged systems are up and to the left, and undercharged systems are down and to the right.) The shape and size of the parallelogram can also indicate airflow or metering device problems. When we use a pressure enthalpy chart to think about efficiency, we can think of the input-to-output ratio. High outputs from low inputs indicate higher efficiencies, whereas low outputs from high inputs indicate lower efficiencies. The coefficient of performance is an indicator of efficiency and is related to EER and SEER, and we can use the net refrigeration effect and heat of compression to think about performance and cost, respectively. To plot a system, start by drawing a horizontal line through the point with the condenser saturation temperature. Then, do the same for the evaporator saturation temperature. Locate the condenser outlet temperature right outside the curve and draw a vertical line that intersects both horizontal lines. Then, plot the evaporator outlet temperature and compressor inlet temperatures; use them to draw a diagonal line along a line of constant entropy. Learn more about Eugene's book at https://www.escogroup.org/training/pressureenthalpy.aspx. Use the code hvacschool22 or hvacschool23 to receive a 10% discount. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan introduces the Sensi Touch 2 smart thermostat for #HVAC. He covers its capabilities, including its ability to connect to up to 15 room sensors and its privacy-first approach to data collection and storage. Learn more about the Sensi Touch 2 at https://hvacrschool.com/touch2. The Sensi Touch 2 is thin and sleek, has a bright display, and comes in white and black versions. It also helps you monitor your system performance by generating usage and efficiency reports. In addition, it will allow customers to receive alerts and maintenance reminders. The actual thermostat has all of the typical control terminals, including ACC+ and ACC- to allow you to connect accessories like dehumidifiers. You may also purchase the common wire kit if there isn't an existing common wire. The Sensi Touch 2 integrates with the Sensi app, which allows you to set up the Sensi Touch 2 and receive data in a single platform. You can also add your company information to the thermostat via the app, which lets your customers know who to call when they receive an alert or reminder. The app also allows you to set schedules and has optional geofencing capabilities. Sensi room sensors measure temperature and humidity, allowing customers to prioritize certain rooms or seek a balance across multiple rooms. Unlike some other manufacturers that may sell user data for marketing purposes, the Sensi Touch 2 will not sell the data that it collects, and the company has a privacy pledge. If you're interested in becoming an #HVACpro and want to learn more about #contractor branding for the #SensiTouch2 #smartthermostat, visit https://hvacrschool.com/sensi. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this 3D video, we show how a typical refrigeration cooler works and focus on pump down refrigeration. This video is narrated by Corey Cruz (BadTXV on TikTok) and shows the refrigeration cycle and automatic pump down for a medium-temp R-404A walk-in cooler. Automatic pump down is a common control strategy used in refrigeration. It automatically pumps refrigerant on the low side of the system into the condenser and receiver whenever there isn't a call for refrigeration; common scenarios include the defrost cycle and when the box temperature has been satisfied. Pumping a system down protects the compressor by preventing refrigerant migration during the off cycle and keeping vapor refrigerant from cooling and condensing to a liquid in the compressor. Liquid refrigerant in the compressor can severely damage the compressor, including causing mechanical wear and flooded starts. An automatic pump down system has three main control components: thermostat, liquid line solenoid, and low-pressure controller. The thermostat is typically mounted at or near the evaporator head unit in the box. Its sensor reads the return air temperature. The thermostat's relay contacts close on a rise in temperature, causing power to pass through the contacts to the liquid line solenoid. The liquid line solenoid (or pump down solenoid) is installed on the liquid line of the system and may be at the evaporator or condenser. During a call for refrigeration, the liquid line solenoid will be energized and will open to allow the flow of refrigerant. It closes during the off cycle and prevents refrigerant flow. The receiver, liquid line filter drier, and sight glass usually come before the liquid line solenoid; a receiver stores excess refrigerant, a liquid line filter drier removes contaminants, and a sight glass will let you know if there is a full line of liquid going to the liquid line solenoid and metering device. The low-pressure controller is installed at the condenser and will be wired in series with the contactor coil. It will cut in or out based on pressure conditions. When setting the cut-in and cut-out setpoints, you will need to consult the manual and be aware of the refrigerant used in the system. To obtain the cut-out setting, subtract the differential from the cut-in setting. When the box temperature rises above the thermostat set point, the thermostat relay's contacts will close and allow power to travel to the liquid line solenoid, which will then open and allow refrigerant to pass to the evaporator. With refrigerant flowing and the pressure rising, the pressure on the low side should then exceed the cut-in setting on the low-pressure control. The contactor coil should then close, completing the circuit and allowing the compressor and condenser fan motors to start operating. During the off cycle, this process is reversed, and the contacts open to remove power to the liquid line solenoid. Pump down begins with the compressor and condenser fan still running. When the suction pressure reaches the cut-out setting, the contacts in the pressure controller open and de-energize the contactor coil, turning the compressor and condenser fan motors off. Many medium-temperature applications don't have a defrost clock and merely defrost during the off cycle. 120v single-phase line power will energize the evaporator fans, liquid line solenoid, and thermostat; the evaporator fans will continue running during the off cycle, and it will supply power to the terminals and their respective wires to the components on the low side of the system. The condenser will receive 208v three-phase power. When the box setpoint is satisfied, or the system is in defrost, the thermostat will prevent power from energizing the liquid line solenoid. Refrigerant will not pass to the evaporator coil, and excess refrigerant will collect in the liquid line receiver. The pressure will drop on the low side of the system; the pump down procedure will continue until the pressure reaches the cut-out setting. The power will then be removed from the compressor and condenser fan motors. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Chris Hughes, Dustin Cole, and A-Team Adam show how to do a real-life blower door test on a house. Chris starts by doing a depressurization blower door test. He installs a speed controller to let the fan cruise itself. He sets the square footage of the house and opts to view the ACH50, or air changes per hour under the test pressure conditions. (ACH represents air changes per hour under normal conditions.) The test conditions allow us to set a baseline and interpolate those measurements and draw a line on a graph when we do multipoint tests. You can connect the TEC Auto Test app to the gauge on a TEC blower door, run the tests according to the standards you set in the app, and receive a report through the app. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Chris Hughes from The Energy Conservatory (TEC), Adam Mufich, and George Hughes show how to measure duct leakage to the outside using a blower door. This test is also know as DLTO (Duct Leakage To Outside) Measuring the duct leakage to the outside requires us to use a blower door and a duct blaster. The thermal envelope should be -25 Pascals in reference to the outdoor pressure, and all registers and return grilles should be masked. The test creates something of an air barrier due to the neutralization of pressures; some of the duct leakage stays in the thermal envelope, and not all leakage goes outdoors. Duct leakage that stays inside the thermal envelope leaves occupants with discomfort, but leakage to the outdoors leaves occupants feeling uncomfortable and leaves the building vulnerable to moisture problems. To get the house down to -25 Pascals, you must start the blower door under all of the correct parameters. For this video, the blower door must be set to depressurize inside the building and be configured for a model-3 fan. Once you hit "play" the first time, you want to start the baseline and change the flow to 25 CFM before hitting "play" again. You'll also want a gauge on the duct blaster; you can set the cruise to 0 Pascals and turn on your speed controller. That selection ramps up the duct blaster to pull the duct system under -25 Pascals of pressure to match the building envelope pressure. When the pressure reaches 0, the CFM reading will show you the leakage outside the thermal boundary (leakage to the outdoors). In this case, we're losing 60 CFM to the outdoors. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bert teaches the Kalos techs some strategies for finding target superheat on systems with fixed-orifice metering devices (not TXVs). Whenever we take readings, we should start by knowing what we want our readings to look like; we should know what to expect of a system that is working properly so that we can recognize abnormalities in our readings. Superheat is an especially critical reading because it can let us know a system's risk of flooding the compressor, if the evaporator coil is being fed efficiently (as opposed to overfed or underfed), and the evaporator load, and it can help us diagnose problems with TXVs (on TXV systems). We can measure superheat on the suction line or discharge line, but those superheat values are very different and can tell us different things about the system. Suction line superheat readings that are too high can indicate that we are starving the evaporator, and low superheat readings can indicate that the system is feeding too much refrigerant into the evaporator coil (or that the coil is otherwise not absorbing heat sufficiently). When you have a metering device problem, like a wide-open TXV, the saturation point is a lot higher than it should be because the pressure stays higher and keeps the evaporator coil warmer. To find our target superheat, we need to take the outdoor dry-bulb temperature (sensible heat) and the return wet-bulb temperature (sensible heat + latent heat). You will need a psychrometer, a target superheat calculator (such as on hvacrschool.com or the HVAC School app), and a manufacturer target superheat chart; measureQuick can help you take these measurements. Once you know your target superheat, you can set the charge accordingly. A common rule of thumb is to achieve a 10-degree target superheat for fixed-orifice systems, but the target is variable because the superheat isn't constantly monitored and manipulated by the metering device (unlike a TXV system). On a fixed-orifice system, the target superheat will decrease as the outdoor dry-bulb temperature increases. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan goes over all the features of the White-Rodgers 70 Series thermostats for #hvac, including contractor branding opportunities, and demonstrates a simple, easy thermostat install. The WR 70 Series thermostats come in programmable, non-programmable, conventional, and heat pump varieties. You can get your company name and phone number on the thermostat with contractor branding; to get contractor branding, visit procontractorbranding.com, select the thermostat type you'd like to brand, and upload your logo or fill in your company's name and phone number. You will receive an imprint number that you can take to your local distributor, and they will order thermostats with your branding information; you must order a minimum of 12, and the printing and shipping are free. The White-Rodgers 70 Series thermostats are exceptionally user-friendly. These thermostats come with easy-to-find mode selector switches on the side of the thermostat. They are also easy to install, as they come with level bubbles for easy mounting. Programmable thermostats can also easily have their programming disabled and operate the same as non-programmable thermostats; they come with internal selector switches for the most common operating options. As with all thermostat installations, the first step of the process is to disable the power. Then, you'll want to identify all of the conductors before you start wiring anything up. Once you identify the conductors and make sure you have all of them, you can read the manual and begin installing the thermostat, which can take as little as 5 minutes. The thermostat comes with screws, drywall anchors, and good-quality batteries. Start installing the thermostat by aligning it with the hole; then, you may start putting the screws in. You can then trim the conductors as needed and connect them to the thermostat appropriately. Once the face is back on, you can put batteries in the thermostat and go through the installer setup (if needed), including minimum and maximum temperatures. Be sure to let us know how #contractorbranding has turned out for your company and what you think of the #70series #thermostat! Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bert teaches a practical training class on manometers. In air conditioning applications, we commonly use manometers to measure static pressure, but they may also measure gas pressure in furnaces and pool heaters. Static pressure refers to the pressure acting on the inner surfaces of the ducts in HVAC systems, and it is affected by airflow resistance; we can think of static pressure as an indicator of airflow. The filter and the coil are also sources of airflow resistance, so we often see static pressure drops across those components. Static pressure may either push against the ductwork (positive, on the supply side) or pull against it (negative, on the return side). Manometers measure this static pressure in inches of water column. We can find the total external static pressure (TESP) by placing one manometer probe above the filter and another just above the blower and adding the readings to see how much airflow resistance that blower has to overcome. You can compare the measurement with the TESP on the data tag, which shows the static pressure conditions under which the unit was tested by the manufacturer. The MERV rating on the filter can affect your return static pressure reading; higher MERV ratings can reduce the static pressure on the return side; we can test the actual resistance by measuring static pressure across both sides of the filter: in the return and between the filter and the coil. Dirty coils or filters can reduce the supply static pressure and will make the TESP low if you measure static pressure before the filter in the return, which can be a misleading airflow indicator. Evaporator coils will always cause a pressure drop, but clean coils usually cause a pressure drop of less than 0.1 inches of water column, so a large amount of soil can increase that pressure drop significantly. Manometers have pressure probes with holes on the side; the probes should point in the opposite direction of airflow to yield the most accurate readings. When using a manometer as a diagnostic tool, you can take readings with and without the filter to see how much it may be contributing to the static pressure drop. We typically want to see a static pressure of less than or around 0.5" WC; once we reach 0.8" WC or higher, we start to see reduced blower motor efficiency, shorter blower lifespans, and more issues. You can also use manometers to locate duct restrictions; collapsed ducts will cause the static pressure to skyrocket as the airflow reaches the restriction, but visual inspections may be more useful if you suspect that the ducts may have collapsed. If you want to figure out the static pressure drop across the coil and place your manometer probe before the filter or immediately before the blower (above the coil), you will have negative static pressure. Some diagnostic apps may have trouble calculating TESP readings in those locations, so you may have to do the math yourself to figure out the pressure drop across the coil. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan and Bert unbox and install THE integrated furnace control for every service van: the White-Rodgers 50M56X-843 IFC. This IFC comes with a hot surface igniter, can be easily configured with the WR Connect app, and replaces over 550 OEM parts for systems with PSC and ECMx motors. Learn more about the 50M56X-843 at https://hvacrschool.com/wrhsi. Inside the box, you will find the actual control, the 120v silicon nitride hot surface igniter, mounting screws, mounting screws, mounting standoffs, spade terminals, and an instruction sheet. You can configure the control without a power source before installation using near-field communication (NFC) technology with your smartphone. The White-Rodgers Connect app allows you to configure the control using the cross-reference part numbers. Prior to installation, shut off the power and confirm that there is no power going to the unit. Then, you can remove the old board; it is a good idea to take a picture of the board prior to removal so that you can see how everything was plugged in, but the unit's wiring diagram will also come in handy. Once you have configured the board using the WR Connect app, you may begin installing the control by using the mounting standoffs and screws to mount the IFC in the unit. Once the IFC is in place, you can begin wiring it in. The box comes with wiring instructions to help you wire the transformer, neutral, and low-voltage wiring. Then, you can add the plugs. The board doesn't require you to use harnesses; you can simply plug the OEM plugs into the control. If you install the control on a system with a PSC blower, you'll plug wiring into the top of the control; wires for ECMx blower motors will be plugged into the right side of the control. The control also has one low-voltage plug where all of the low-voltage wires connect, allowing every low-voltage wire to be connected and disconnected from the control all at once via the plug. The board also allows for a two-stage setup on units that require it. The board has a digital display, allowing it to show error codes easily. The board face contains a list of error codes and run codes, which allows you to understand the status of the board. With the board in place and fully configured, you can install the hot surface igniter. Once the board and igniter are installed, you may test the unit. When you restore power, the IFC will take a moment to understand the OEM's logic and adapt to its current application. Then, the furnace will go through its sequence of operations. The digital display shows the operating mode (heating or cooling) and reports the flame sensor microamp reading. Buy your virtual tickets or learn more about the HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This video is of a presentation from the 4th Annual HVACR Training Symposium: “Demystifying the Thermostatic Expansion Valve” by Jim Jansen from Parker-Sporlan. He also talks about the role of the distributor and goes over some Sporlan TXV designs. The refrigeration circuit has four key components: compressor, condenser, metering device, and evaporator. We can use a few different types of metering devices, including thermostatic expansion valves (TXVs or TEVs). TXVs have a sensing bulb and capillary tube, which make up the powerhead. The valve itself has an inlet and an outlet, a diagram, two push rods, a pin working in conjunction with a port, and a closing spring that adjusts the inlet size. Some of them come with a removable strainer assembly to help control contamination. A few valves have a stem that allows you to adjust them. The TXV responds to the temperature at the evaporator outlet to modulate the orifice size. The sensing bulb will pick up the suction line temperature and apply pressure to the diaphragm accordingly, which provides an opening force. A closing force that acts against the opening pressure is provided by the spring and an external equalizer. The orifice size is determined by the way these three forces act on the valve. TXV manufacturers typically want to prevent inlet pressure from acting on the valve. TXVs control superheat by controlling the size of the orifice—and the way it meters refrigerant. Adjustable valves allow you to control preload from the spring, which doesn’t change the valve capacity but does allow you to control the superheat that the TXV aims to maintain. We want to make sure the superheat allows us to maximize capacity without flooding the evaporator. Some TXVs have bleed ports, which allow inlet high-side pressure to bypass the part of the valve that regulates the incoming refrigerant pressure. This feature comes in handy when the compressor has a low starting torque; it allows the high and low sides of the system to equalize on the off cycle. You will want to make sure that you don’t replace non-bleed TXVs with one that has a bleed port or vice versa. Valves may be internally or externally equalized. Internal equalization requires the valve to sample evaporator pressure, typically at the outlet fitting of the expansion device. External equalization requires a third fitting on the valve for an equalization line that samples pressure on the suction line. Mounting the valve properly will allow you to tap into the suction line properly, and it will allow you to get solid contact with the suction line to control the superheat most effectively. Residential HVAC superheat values tend to be within the 8 to 12-degree (Fahrenheit) range, and evaporator temperatures may be as high as 52 degrees or as low as 40 degrees depending on the manufacturer. Commercial refrigeration evaporator temperatures can reach subzero temperatures (Fahrenheit). Common issues with TXVs include starving, overheating, or hunting. Starving results in high superheat, and overheating results in low superheat (or none). Hunting refers to excessive modulation and may indicate problems with your TXV setup. TXVs may also leak and prevent the bulb from responding to the suction line temperature; leaking valves need to be replaced. Distributors help mix the vapor and liquid coming out of the TXV, and there is an additional pressure drop associated with them. Systems with distributors require externally equalized valves. Buy your virtual tickets or learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This 3D animation goes over heat and comfort basics, especially as those things relate to heat transfer in residential structures and HVAC systems. Heat losses occur when heat leaves a structure, and heat gains occur when heat enters a structure. When there are significant heat losses, a furnace or heat pump adds BTUs of heat to compensate for those losses. When there are significant heat gains, an A/C system or heat pump removes BTUs to balance out the gains. BTUs (British thermal units) are units of heat equivalent to the amount of energy it takes to raise the temperature of 1 pound of water by 1 degree Fahrenheit. Heat transfer occurs in three different ways: conduction, convection, and radiation. Conduction occurs when two substances of different temperatures make direct contact with each other; the hotter object will transfer its heat to the cooler object until both objects are at the same temperature (equilibrium). We use insulation to oppose conduction and reduce the rate of heat transfer. Convection occurs when molecules of fluids (vapors and liquids) move and bring their heat with them. Our homes experience temperature changes due to convection when we have gaps or cracks in the structure or leave windows or doors open; we refer to air movement via these sources as infiltration and exfiltration. Radiation occurs when objects give off or absorb heat via electromagnetic waves. When the sun shines on surfaces in the home through glass windows, the room gets warmer because the heat from the sun's electromagnetic waves passes through the glass and warms the surfaces in the room. Our bodies also give off heat via radiation, which is why you feel cooler when you stand near a cold wall; your body gives off heat to the cooler surface of the wall. Heat can be sensible or latent. Sensible heat is heat that we can measure with a thermometer, and latent heat cannot be measured because it refers to the heat required to complete a phase change (the temperature does not change). It takes 1 BTU to raise the temperature of a pound of water by 1 degree Fahrenheit, but it takes about 970 BTUs to change a pound of 212-degree liquid water to 212-degree water vapor. There is a lot more energy involved in phase changes than mere temperature changes; the latent heat required to change solid ice to liquid water or vice versa is the latent heat of fusion (144 BTUs), and the latent heat required to change liquid water to water vapor or vice versa is the latent heat of vaporization (~970 BTUs). Larger heat sources (including flames or electric heat) transfer more heat than smaller ones, meaning that they transfer more BTUs and can make phase changes happen more quickly. Latent heat is important for HVAC applications because most HVAC systems in temperate or humid climates also remove moisture from the air. Many people will notice that cooler air sinks and warmer air rises. Cooler air is denser than warm air, which perpetuates the common but slightly misleading idea that "heat rises;" heat itself doesn't rise or fall. Warm air will rise and go into the return, where it will pass over the evaporator coil. The refrigerant in the evaporator coil can absorb a lot of heat because it is boiling and requires a large number of BTUs to complete its phase change to a vapor. As heat transfer happens, some of the moisture in the air will also condense on the coil; the coil must be cold enough to be below the dew point for this to happen. We can calculate how much heat enters and leaves a home by using ACCA Manual J. This manual allows us to use local climate conditions and consider the structure to design an HVAC system tailored to a home's BTU gains and losses. However, the real conditions may vary due to human activities, especially because our bodies add heat to structures via conduction (touching surfaces), convection (movement), and radiation. Humans also add latent heat when they exhale. Heat gains added by humans or animals in a structure are known as internal gains. Buy your virtual tickets or learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bert goes over some of his top callback prevention tips with the Kalos techs. He covers some bad habits and goes over the attitude, training, and knowledge necessary to prevent callbacks. We can prevent callbacks by focusing on our mindset; having the willingness and taking the time to close out everything completely stops us from making silly, preventable mistakes during service. Managing our habits and having the right knowledge/skills are important, but the mindset allows us to keep perfecting our work and staying positive over the years. It's also possible to have a great mindset and bad habits, like poor organization habits, or you can have a great mindset and lack the training or experience needed to complete a job without a callback. Those can hold you back temporarily, but a positive mindset can help you overcome those obstacles. When we combine a positive mindset with good habits, we lay down patterns of work that keep us in the right mindset to prevent callbacks. Habits include things we do at work as well as before and after work. Making a habit of checking a call the night before and doing a final walkthrough before leaving the job can help you prevent callbacks. On the other hand, allowing head trash to accumulate is a symptom of a negative mindset and can also hold you back significantly, especially as you spend more time in the industry. A negative mindset will keep you from enjoying your job, makes you susceptible to making mistakes that result in callbacks, and creates a cycle of negativity. Buy your virtual tickets or learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Jim Bergmann from measureQuick compares volume flow rate and mass flow rate as those topics relate to air movement in HVAC/R. This video was shared with us by Adam from HVAC Overtime; you can subscribe to HVAC Overtime at https://www.youtube.com/@HVACOvertime. One of the most fundamental equations that drive the work we do is Q = mass x specific heat x ΔT. This is the equation we use to find BTUs. We can use a similar equation to figure out how many pounds of air we're moving if we already know how many CFM we're moving. Air density will affect the mass of the air and CFM, so that requires us to differentiate between standard CFM (SCFM) and the actual CFM (ACFM). ACFM differs from SCFM in that it factors in the effects of relative humidity, temperature, and barometric pressure on the mass of the air. Depending on the type of fan you have, you may really have a variable mass flow rate with a constant volume. SCFM measurements are based on air at sea level, 68.3 degrees Fahrenheit, and 0% relative humidity (0.075 lbs/ft cubed). Higher relative humidity levels will reduce the density of the air, as water (H2O) is lighter than nitrogen (N2) and oxygen (O2), which make up most of our air. MeasureQuick's ACFM accounts for those humidity changes as well as pressure and temperature deviations from the sea-level, 68.3-degree standard. Fans move a constant volume of air (SCFM), but the mass flow rate (ACFM) is much more variable based on location and climate. You can also use a psychrometric chart to help you with ACFM. The line of specific volume for 68.3 degrees and 0% relative humidity on a psychrometric chart also happens to be the inverse of the 0.075 lbs per ft cubed, which is the SCFM. (The ACCA manuals use SCFM for equipment design.) ECMs work off RPM and torque; changes in air density affect the torque and affect ECM outputs. Since we're cooling the mass of the air, not the volume, it also helps to think about ACFM beyond ECM outputs. Buy your virtual tickets or learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Eric Kaiser and Bill Spohn team up to give their HVACR Symposium presentation about thermal imaging theory & practice in HVACR applications. They highlight the uses and limitations of thermal imaging to set realistic expectations for using it. Thermal imaging is especially useful for making temperature comparisons because it helps us and our customers visualize the temperature differences between multiple points. A thermal imaging camera looks at surface temperatures by picking up infrared waves and turning them into visual light images, so it can’t “see” temperatures through glass or other surfaces. When you’re using thermal or IR cameras, you need to make sure you can use them safely; you don’t want to stick your hand inside of operating equipment and can use tripods, wireless technology, etc., to keep yourself safe. You also want to be aware that certain surfaces respond differently and must make a few corrections for some surfaces. Setting the span and the level is also important for the proper use of a thermal imaging camera; the level sets the range for the color palette on your screen, and the span is the differential; these will determine how the camera interprets temperature, especially when measuring reflective surfaces with low emissivity. Unlike span and level, focus cannot be changed in software, so you must make sure your image is focused before you take it. You’ll also want to follow a pattern or path to keep track of your work. Most importantly, you’ll want to know what your equipment should look like under normal operating conditions vs. abnormal conditions so that you can verify problem areas. You will want to make sure that your pictures are in focus. Thermal imaging cameras can be useful for helping you identify heat in electrical components and could help you identify a loose connection. However, the camera could also be picking up a heat source near the electrical parts, including your own body heat. A thermal imaging camera can show you purely thermal images, fusion images (thermal and visible), and visible. It is important to use the visible image as a reference to the thermal image, as the thermal images could show reflected heat signatures of people or things that aren’t actually in the frame. A picture-in-picture image mixes a larger visible image with a smaller thermal image; in these images and fusion images, the alignment is critical. Thermal imaging is a valuable tool for qualitative data and allows you to compare surface temperatures quite effectively, but it can get tricky when you get into quantitative measurements because of the emissivity. Emissivity allows us to evaluate a surface’s ability to emit heat (vs reflect it) compared to a perfect black body, which has an emissivity of 1; all other emissivity values are less than 1. Tape can have a different emissivity than the metal you’re measuring, so you need to keep that in mind when you’re trying to take pictures of things with two different thermal masses. When you’re dealing with reflective surfaces, you can put a target spot on the surface with a known emissivity in the editing phase. Thermal and fusion images are exceptionally good at helping you find loose electrical connections, misaligned belts, air leakage, and overheating (poorly lubricated) bearings. Temperature differentials between the indoors and outdoors as well as level and span adjustments can make these issues easier to see. You can also use thermal imaging cameras on entire buildings to see which spots are hotter than others. Buy your virtual tickets or learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Jim Jansen from Parker-Sporlan gives his presentation, “Contaminant Controls System Clean-Up with Filter Driers,” at the 4th Annual HVACR Training Symposium. He explains the parts and functions of filter driers and covers some Sporlan products. The basic refrigeration circuit includes an evaporator, compressor, condenser, metering device (which comes in many varieties), and the tubing between those main components. Even large DX refrigeration systems have those components (though often with multiple evaporators or compressors and other ancillary components). Contamination happens when we get unwanted material in an unwanted location; it can happen in many different ways and often disrupts the proper operation of the controls in a refrigeration system. Filter driers in various locations can help protect the system components from contamination. A filter drier on the liquid line is often positioned close to the metering device (and liquid line solenoid in circuits that have those). These filter driers catch contaminants to ensure that only oil and refrigerant circulate through the system, not acids, wax, or varnish. Moisture is a common source of contamination, and acids can form from it as well. Catch-All is Sporlan’s brand of liquid line filter drier. As a result, filter driers contain a desiccant core to remove moisture, acid, or wax from the system via adsorption; the desiccant material will dictate what the desiccant can remove, and these materials include molecular sieve (water), activated alumina (acid), and activated carbon (wax or oil). Different desiccant types also have different pore structures, which also contribute to contaminant removal. Sporlan makes replaceable cores of all materials. Filter driers are often used to help clean up a system after a burnout. When you suspect a burnout, an acid test kit (manufactured by several companies including Sporlan) will let you compare an oil sample to a color chart that confirms or denies the presence of acid. Using moisture indicators can also help prevent the formation of acid before the system experiences a burnout. Suction filters go on the suction line and may offer optional bypass; these can protect your compressor and stay in the system for an extended period of time. Suction filter driers, on the other hand, tend to be used immediately after burnout for cleanup and are not permanent components. Liquid line filter driers will need to be added or replaced when there is a new system installation or replacement, the system is opened, the pressure drop exceeds 5 PSI, there is moisture or acid in the system, and after burnout cleanup. An oversized liquid line filter drier should be installed during cleanup, and severe compressor burnout should also warrant the installation of a suction filter drier. To remove a filter-drier, use a proper tubing cutter whenever possible, and you’ll want to use the typical brazing best practices when brazing a new one in. Many filter driers can remove contaminants as small as 20 microns in diameter; being able to remove these tiny contaminants will have a significant impact on the lifespan of the bearings in the compressor. Abrasive particles as small as 5 microns in diameter can reduce bearing life. Sporlan also makes oil filters to protect reciprocating and scroll compressors from contaminants in the oil. However, we don’t want to remove moisture with the oil filter because that could dry out the oil, so we want to make sure we’re removing system moisture from the refrigerant in the liquid line. Buy your virtual tickets or learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan gives a product overview of the White-Rodgers Integrated Intelligent Valve Retrofit Kit (50I56D-905). Like other White-Rodgers products, the Integrated Intelligent Valve Retrofit Kit is a universal part that replaces many OEM controls; this control works for ICP and Lennox brands. This kit replaces outdated first-generation smart valve systems with a modern, reliable gas valve, control board with selectable OEM blower delay DIP switches, and 120v hot surface igniter with a flame sensor. The kit also has a fault recall feature and allows for advanced diagnostics with standard furnace troubleshooting. This kit is a cost-effective solution and comes with a 5-year warranty. Compared to its competitors, the White-Rodgers Integrated Intelligent Valve Retrofit Kit comes with everything in the box, including a durable silicon nitride igniter and reliable standard mechanical gas valve, and it has a longer warranty, comes with a fault recall feature, and is generally more cost-effective. To learn more about the White-Rodgers Integrated Intelligent Valve Retrofit Kit and watch the official installation guide, visit https://hvacrschool.com/intelligentvalve. You can also use the White-Rodgers app to look up more information or visit our partner page at https://hvacrschool.com/partner/emerson-white-rodgers/intelligent-valve-retrofit-kit/. Buy your virtual tickets or learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

The 4th Annual HVACR Training Symposium hosted an electrification panel with Kimberly Llewellyn (METUS), Bill Spohn (TruTech Tools), and Jim Bergmann (measureQuick). They answered audience questions and discussed some possible opportunities and areas of concern as the HVAC industry faces electrification. The conversion to electrical vehicles and appliances is inevitable, and that will likely result in a shift toward heat pump technology in the United States, among other technologies like heat pump water heaters. However, there isn't really a solid definition of what electrification entails, and many contractors have reported that their customers haven't asked them about it yet. When it comes to educating customers, the industry needs to be able to give non-technical answers about the benefits of electrification and what they can expect from electric appliances and HVAC equipment. Electrification has brought a lot of frustration to the trade, especially because the movement is largely being led by smart, well-intentioned people who are, unfortunately, out of touch with the realities of the HVAC industry. Mass electrification may strain communities and make for a rocky transition if it happens too quickly. The industry as a whole also doesn't have the skill set to install electric heat pumps that maintain comfort the same way that a furnace or A/C system can. Improvements to our tool technologies can help, but we need to train HVAC professionals to install heat pumps correctly for the tools to reach their full potential. Hybrid solutions could help, but there may be energy costs associated with those systems. However, dual-fuel systems have the potential to offer long-term savings and provide a backup system for extreme weather in retrofit systems. Sometimes, the buildings need to be improved; insulation and other sorts of modifications could support heat pump technologies by upgrading the building envelope. Duct leakage is a significant problem in many HVAC systems, and heat pumps won't function as they should when the duct leakage is significant. In many places, the building envelope and electrical infrastructure need to be upgraded. The supply chain issues and costs of upgrading the infrastructure are also current challenges to electrification. In places where natural gas is cheap, there may not be a clear benefit to installing heat pumps for your customer. However, the savings tend to be gradual, and mass electrification isn't happening everywhere all at once. In areas that still use steam boilers (which have dynamic losses), heat pumps can support existing technologies in shoulder seasons, especially if they're used in lieu of an A/C system. Energy banking could support electrification efforts, but it could be relatively limited to commercial HVAC. The lack of training is a tricky challenge to tackle, especially amid a race to the bottom from a pricing standpoint. Certification is also tricky due to the lack of consistent, mandatory standards in the industry. Even though there are some organizations that set standards, those standards are largely voluntary. In too many cases, technologies like measureQuick are seen as a burden rather than a tool; however, technicians who understand the value of their work and take pride in it will be more likely to embrace those technologies and the literature at their disposal. When people feel like they can make a difference, we may see a change in morale and a shift for the better, but we're just not there yet. Buy your virtual tickets or learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Ty Branaman gives some of his insight about educating & training Gen Z. He gave this presentation at the 4th Annual HVACR Training Symposium, and you can still buy tickets to access all sessions virtually. To be able to educate, train, and recruit Gen Z, we need to be able to understand them. Their interests and communication styles differ from the generations before them because they grew up in different environments. Previous generations also tend to romanticize the past, including previous generations’ work ethics, which leads them to have a negative outlook on the new generation; this is a pattern we’ve seen for over a century, and we must be careful not to slap that label onto Gen Z. At the end of the day, Gen Z is here to stay, and they’re just people who deserve to be viewed with empathy and open-mindedness. Generation Z is especially connected and tends to be adept with technology, but they’ve been exposed to more school violence than previous generations. Gen Z has also experienced two major economic recessions, which have shaped their outlook, and they want to make sure they have job stability, flexibility, and good compensation. That means the HVAC industry needs to think about how Gen Z employees are compensated, especially if they also have to buy tools and can earn almost as much money in a food service or retail job. Gen Z needs a career path and frequent evaluations with specific feedback. Those things show that HVAC business owners care about Gen Z and are invested in their well-being. Gen Z’s world moves quickly, and the HVAC industry will need to adapt to that. Instead of being interested in being told WHAT to do, Gen Z also tends to want to know WHY they should do something. That combination of practices will be more likely to keep Gen Z-ers interested in their work if they decide to enter a career in HVAC; they want to be in charge of their life and be treated with respect. Members of Gen Z tend to be more individualistic and are more likely to choose nontraditional postsecondary paths; they want to write their own stories and understand that a traditional 4-year college education isn’t always the right choice for them. As they learn more skills, they learn and grow, and they are likely to find a trades job that suits them and be fulfilled by a skilled trades career. Part of that job fulfillment comes from responding to events that are important or require a sense of urgency, and they want their good work to be acknowledged. Connectivity is important to Gen Z, and we would be wise to embrace their enthusiasm to share their work on social media or make videos of their workmanship. When they take pictures or make TikToks of their work, they’re showing people that the trades are cool, which can help with the recruiting aspect of educating and training Gen Z. Embracing diversity will also help the HVAC/R trades recruit Gen Z, especially as more women and other traditionally underrepresented groups want to start getting into the trades. When we respect people who have different backgrounds, beliefs, and characteristics, we can work together to get jobs done. Gen Z is more culturally diverse than previous generations, and we would be wise to embrace that diversity and welcome people from all walks of life. Consistent positive communication will be crucial when it comes to keeping Gen Z. Being able to set expectations for incoming Gen Z-ers, welcome them, and show them a possible career trajectory will go a long way. The same courtesy we show our customers should also be shown to our fellow tradespeople. As long as we’re empathetic and appreciate Gen Z-ers for their unique abilities and good work ethic, the HVAC/R industry will have a better time recruiting, educating, and training them. Buy your virtual tickets or learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bert the trainer and Kyle introduce the NEW Viper WetRag Heatshield pad from Refrigeration Technologies. The flame-resistant Heatshield pad is flame-resistant and withstands temperatures up to 2500 degrees Fahrenheit, making it the perfect protector for the air handler while Kyle is brazing after replacing the evaporator coil. You can also get it wet for added heat absorption and flame resistance (it can be used wet or dry). The pad folds around the line set or filter drier and can cover the heat-sensitive PVC of condensate drains. Refrigeration Technologies will officially release the Heatshield soon, and you'll be able to find it at a supplier near you. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bert brings you Top Takeaways from HVACR SYMPOSIUM 2023. He interviews several symposium attendees, including some speakers and sponsors, to hear about some of their 2023 symposium highlights and tips. Ty Branaman was a returning speaker at this year's symposium. He keeps coming back because he enjoys seeing so many dedicated people come together to learn and connect with each other. Ty's top tip for people in the industry is to never stop learning. He's always learning about airflow and feels that the symposium challenges him to keep learning and growing. Dr. Allison Bailes spoke at this year's symposium and enjoyed seeing so many field professionals come to the symposium with the intent of putting everything they've learned into practice. Dr. Bailes's tip is not to believe everything you're told and to consider the bigger picture. Longtime contributor Eric Kaiser enjoys learning new things, seeing old friends, meeting new friends, and having great conversations at the symposium. His top tip is to throw your ego out the window and be willing to learn. His wife, Rachel, is also amazed by how much the attendees want to learn and how engaged they are. RACT manual co-authors Jason Obrzut and Eugene Silberstein are excited to see attendees who want to leave the trade better than they found it. Andy Holt, Bill Spohn, and Mike Pastorello also shared their symposium highlights in this video. Buy your virtual tickets or learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bert installs the Emerson White-Rodgers Universal Heat Pump Defrost Board (47D01U-843) on a Carrier heat pump. It is a single-stage universal defrost control that replaces a wide range of OEM parts and can be configured to do time/temperature or demand defrost. The Emerson White-Rodgers single-stage universal defrost board comes with the outdoor temperature lockout thermostat, an LED display, short-cycle and brownout protection, self-tapping screws, and sensors in the box. It also has error code recall, so you can see recent error codes. The cross-reference chart is located on the packaging and contains several brands and model numbers. Bert starts by plugging in the thermostat wiring, outdoor temperature sensor, and coil temperature sensor to the board straight out of the box. Before working on the unit, he makes sure the power is off. Then, he takes a picture of the layout so that he can remember how the wiring is configured and what the OEM board's orientation was. In some cases, the OEM will have a thermostat sensor that will be rendered obsolete by the outdoor and coil temperature sensors of the Emerson White-Rodgers universal board. He then mounts the board with the self-tapping screws to secure the board in the best possible orientation. With the board in place, Bert secures the unit's thermostat wires to the corresponding wires on the board with wire nuts. The board allows you to stop the thermostat from bringing on auxiliary heat in some scenarios, so you can break the auxiliary heat signal through the defrost board; you would include the brown wire at the WIN terminal. Otherwise, you would just secure the white wire at the WDX2 terminal under the wire nut. With the low-voltage wiring hooked up, Bert begins wiring the safeties, contactor, and reversing valve. He uses wire nuts on those connections as well, though male spades may also be used. There is also a loss of charge pressure switch in the circuit, which hooks up to the low-pressure switches and will open when there are conditions that resemble low refrigerant charge. Bert makes sure that the fan relay is wired so that it is energized constantly with the high voltage. Then, Bert puts the sensors in optimal locations; the outdoor temperature sensor should be away from direct sunlight, and the coil sensor should make contact with the coil. When everything is in place, Bert cleans up his wiring with some zip ties. With the board fully wired in, Bert restores the low-voltage control power. The board flashes H, indicating that it's in heat (H) and in time delay (flashing). He cancels any calls for heating and cooling and goes through the options until he reaches OE, which allows him to configure the board to match the original manufacturer's defrost cycle. He sets it to 1, which is the setting for Carrier units, and describes the various manufacturer settings compared to the default Emerson White-Rodgers settings. The customizable codes on the LED display include Er (error), Fr (fault recall), OE (quick setup), and then the individual configuration options: dF (defrost type), Et (enable temperature), tt (termination temperature), SS (short-cycle time), r (reversing valve power), Sd (reversing valve shift delay), dt (maximum defrost time), hL (auxiliary heat lockout), Lt (low-temperature compressor cutout), rt (random start delay), LP (low-pressure switch on/off), HP (high-pressure switch on/off), and Bo (brownout protection on/off). Then, Bert tests the system operation to make sure the heat pump will actually switch to defrost mode; he bypasses the time delay and forces defrost. He also runs the unit and heat mode without the fan to cause frost to appear on the coil, which causes the unit to go into defrost by shifting into cooling mode and sending hot discharge gas through the coil. When you're working on systems with these defrost boards, Bert recommends doing a visual inspection and testing the sensors by ohming them out. Check out our recent video all about heat pump defrost at https://www.youtube.com/watch?v=R_gNKOapR7I&ab_channel=HVACSchool. Buy your virtual tickets or learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Andy Holt from Outdoor University is at the 4th Annual HVACR Training Symposium for the first time and Bert asks him some questions about life and HVAC trade. Learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Jim Fultz from Emerson White-Rodgers demonstrates new 50M56X-843, Integrated Furnace Controls Universal Replacement. The new board is two previously released boards 50M56U-843 and 50X57-843 put together into one new product. Learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Mallory David from Parker Sporlan demonstrates ZoomLock MAX and ZoomLock PUSH fittings. Learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Eugene Silberstein and Jason Obrzut from ESCO Institute are back to the 4th Annual HVACR Training Symposium. They stop by to have a conversation with Bert about the event and also share some valuable practical tips for HVAC techs. Learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Creators of A/C Easy Tee Solution Technologies Inc. have brought new Shop Vac solutions they have been developing recently to the 4th Annual HVACR Training Symposium. Chris Eads the President/founder of the company demonstrates them in this video. Learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/

Tony Gonzalez is back speaking and training at 4th Annual HVACR Training Symposium. He talks a bit about the tried and true Job Link tools and also Introduces the all-new Fieldpiece Combustion Analyzer! Learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/

Dr. Allison Bailes from Energy Vanguard is at the 4th Annual HVACR Training Symposium to give his talk ''Solving the Ventilation Puzzle''. He stops by to talk his new book “A House Needs to Breathe... Or Does It?" that covers a lot of the basic building science. Learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Andrew Greaves from NAVAC (He also has Youtube Channel @AKHVAC) demonstrates the new NTB7L Power Tubing Bender. Andrew bends some copper tubes live using NTB7L at the 4th Annual HVACR Training Symposium! Learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/

At the 4th Annual HVACR Training Symposium, Bert catches up with Josh Teekell, the CEO of SmartAC.com, to talk about Smart Maintenance and the company’s low-fault fault detection platform for residential A/C. SmartAC.com is the symposium’s food and beverage sponsor. The program comes with magnetic sensors that are deployed in the supply vent, return vent, and evaporator drain pan. These leads measure the delta T between supply and return, and it measures the condensate to determine the health of the system. This technology can be used to sell maintenance agreements and make them more efficient, which can strengthen customer relationships. The SmartAC.com system allows technicians to analyze data in real-time and contact customers when something goes wrong, allowing them to take a proactive approach. It also allows them to predict problems, especially outside of peak failure times. SmartAC.com has been endorsed by Jim Bergmann. Jim has recently been integrating the SmartAC.com software with measureQuick, which allows technicians to show the customers the performance data and educate them about why it matters, which also builds trust and relationships. SmartAC.com’s program allows HVAC/R technicians (partners) and customers to view an app and watch the performance data. When issues arise, the app offers leads and allows technicians to make the first move if a notification looks concerning; it also gives the customers confidence in the technician’s judgment, as they will be able to see the performance. Learn more at https://smartac.com/. Learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

At the 4th Annual HVACR Symposium, Bert checks in with Nick Stojkovski with INFICON to watch a demonstration of the D-TEK Stratus leak detector and monitor. INFICON is a sponsor and loyal supporter of the HVACR Training Symposium. The D-TEK Stratus makes leak detection easy by measuring and displaying the PPM, meaning that you will see higher numbers as you get closer to a leak and lower numbers as you move the probe away from it. This sort of guidance, cloud hunting, makes it easier to pinpoint a leak. You can also make use of Pinpoint Mode, which auto-zeroes the detector in high concentrations of refrigerant or CO2 to identify a notable concentration that might indicate a leak. The product is also highly serviceable and comes with a replaceable hydrophobic filter and a removable probe, which is also field-replaceable. D-TEK Stratus leak detectors also come with replaceable lithium-ion batteries and a charging cradle. The D-TEK Stratus has three different sensors for refrigerant, hydrocarbons (R-290 and R-600), and CO2. These sensors can be switched out depending on what you need, use infrared technology, and are also more robust than previous models. Learn more about the 4th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Check out the INFICON D-TEK Stratus at https://www.inficon.com/en/products/d-tek-stratus-refrigerant-leak-detector. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Learn everything about heat pump defrost with this video lesson and unboxing video from Bryan and Bert. This video features the Emerson White-Rodgers Universal Heat Pump Defrost Control, and you can learn more about that defrost control at http://www.hvacrschool.com/wrdefrost. Heat pumps have to operate in cooling mode to melt the ice; the reversing valve switches to send the discharge gas to the outdoor unit (as it would in cooling mode). The coil has to be colder than the ambient temperature to absorb heat from the outdoors, and there is often moisture on the coil; under those conditions, frost accumulates on the coil. A little bit of frost is to be expected, but excessive frost indicates that a heat pump's defrost cycle isn't working as it should. Bryan and Bert force the unit into defrost, and they start off by running it in heating mode. The outdoor unit blows cool air, not hot air, in heating mode because it is absorbing heat; the reversing valve is also de-energized, and you would not pick up voltage between O and Common on the defrost board. Some units have thermostats that monitor the coil temperature; other units may use thermistors. Regardless of operating mode, the contactor must pull in, so there should be around 24v between Y and Common. In this particular unit, a bimetallic disk will snap shut at 32 degrees Fahrenheit (0 Celsius) to initiate defrost. You can check the defrost board to see if the disk is opened or closed by checking for 24v power; if it's missing, then the disk has closed. You can jumper out the pins on the board and speed up the unit's operation to test demand defrost, but that method doesn't allow you to troubleshoot the thermostat. The board in this video (White-Rodgers Universal Defrost Control) can be programmed to go into defrost for a maximum period of time (10 minutes, in this case) or come out of defrost at 65 degrees Fahrenheit. You can also use the board to set defrost at timed intervals (in this case, 30, 60, or 90 minutes). The speedup function on the White-Rodgers universal defrost control allows you to bypass the short-cycle delay or initiate defrost to test the board. To initiate defrost, the board energizes the O terminal, which allows hot discharge gas to flow through the coil with frost buildup without the fans running. When the target temperature is hit, the defrost will end. While the unit is running in the equivalent of cooling mode in defrost, the defrost board also brings on the auxiliary heat strips to keep the occupants from getting cold. Some boards also have a quiet mode to make the defrost process quieter. The Emerson White-Rodgers Universal Defrost Control replaces most single-stage defrost controls and comes with a comprehensive guide for user-friendliness and education. It also comes with two thermistors for demand defrost and a chart with the corresponding temperature and resistance readings; you can test thermistors by ohming them out and comparing them to that chart. This control also has time delays to prevent short cycling, a user-friendly and interactive display, and brownout protection. Learn how a reversing valve works at https://youtu.be/lFV3xT5HCH0. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Craig Migliaccio, aka AC Service Tech, returns to the podcast to share his knowledge about mini-split install & service. He also talks a bit about his upcoming book, “Inverter Mini-Split Operation and Service Procedures.” Mini-splits are unique because they are compartmentalized in ways that traditional central-air ducted systems are not. Mini-splits come in many varieties, including ducted and ductless types, as well as multi-zone types. Many are inverter-driven and have more electrical efficiency as a result and can vary their capacities based on load variation. Mini-splits have metering devices at their outdoor units, and these devices may be electric expansion valves (EEVs) or capillary tubes. Inverter mini-splits also don’t have filter driers because their PVE oil doesn’t have the same acid concerns as POE oil, and they don’t have traditional liquid lines. Flare connections are also critical when installing ductless systems, especially because you want systems to be tight to prevent leaking and contamination. Craig likes eccentric flaring tools with offset cones, and he recommends using flare nuts from the equipment manufacturer, not the line set manufacturer. He covers other flaring best practices as well. The charge is quite small in mini-splits, so weighing the charge and being careful and deliberate during charging is critical. Refrigerant leaks can also be highly problematic; corrosion and poor flare connections are common causes of leaks. Craig and Bryan also discuss: Hyper-heat systems Coefficient of performance (COP) and BTU output Moving between PSC and ECM or inverter technologies Mini-splits vs. VRF/VRV technologies Pressure testing and leak detection Compressor diagnosis Thermistors and electrical resistance Heat sinks and mounting circuit boards Selecting a location to install a mini-split Things to consider when checking the charge Why measure superheat and subcooling? Cleaning and maintenance best practices Check out Craig’s YouTube channel at https://www.youtube.com/@acservicetechchannel. Starting January 1st, 2023, you can buy Craig’s book on his website, which has a bunch of other good resources. Visit that site at https://www.acservicetech.com/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this video, Dirk Nauman, the creator of the HVAC Simulator, shows you the proper installation of the Emerson White-Rodgers All-Spark ignition module. You can learn more about the All-Spark at https://hvacrschool.com/allspark. Dirk is replacing a Honeywell intermittent-pilot igniter with a round spark connector, also called a rajah. To configure the All-Spark to the original igniter’s settings, Dirk uses the Emerson White-Rodgers Connect App. Then, he simply installs the All-Spark wire by wire. After installing the All-Spark, you simply have to start up the furnace and test it. You can then use the White-Rodgers Connect App to help with troubleshooting and diagnostics, or you could simply use it to keep an eye on the system’s status. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Dr. Allison Bailes from Energy Vanguard joins the podcast to answer the age-old question: do houses need to breathe? He also talks about his new book, “A House Needs to Breathe... Or Does It?" You can purchase that book directly through the Energy Vanguard site at https://energyvanguardstore.com/ or on Amazon. HVAC professionals can benefit from learning about building science because there is a lot of overlap between the two, and an HVAC technician who knows about building science can set themselves apart in the market. In short, Dr. Bailes doesn't think a house needs to "breathe," especially if a house brings in low-quality air, especially humid air, through gaps and cracks. Some people also use the term "breathe" differently; some may be referring to leakiness, and others may refer to drying out a house. It is necessary for a house to be dry, but we want to make sure that fresh air is controlled. If you build a home tightly, you have to ventilate it correctly. We have to control air, liquid water, water vapor, and heat. Heat is especially complicated, as it has three different ways of moving and can come in sensitive and latent varieties. One way of controlling those is through control layers like vapor barriers, though these aren't always needed; we must understand the vapor flow to determine if a vapor barrier is necessary. Dr. Bailes and Bryan also discuss: Energy Vanguard's resources The chapters of "A House Needs to Breathe... Or Does It?" IAQ - filtration, humidity control, ventilation, and source control Challenges with attic air Dr. Bailes's book-writing process The HVACR Training Symposium and other events w/ Dr. Bailes Keep up with Energy Vanguard, read the blog, and subscribe to the weekly newsletter at https://www.energyvanguard.com/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bert shows his Carrier Infinity blower diagnostic process using a multimeter. In a Carrier Infinity system, the blower is in constant communication with the board. However, when the blower motor doesn't communicate back, an error code shows up. In this case, we have an error code 44, which may point to a failed module or board. Instead of replacing the module and using the process of elimination to diagnose the problem, you can use your meter to see how much voltage the board is actually sending to the module. In this case, Bert reads ~240v going into the blower motor. Then, Bert checks the control voltage and sees if there is between 12 and 13 DC volts of power between the red wire and common at the blower plug; the readings are right on target. The reading between the common and yellow wire should be around 5 DC volts; Bert reads ~1.6 volts, so the board isn't sending the proper communication voltage. In the end, Bert would have replaced the wrong part if he had immediately replaced the module without testing it with a meter. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This 3D animation shows how a typical 40VA residential or light commercial transformer works. Transformers can either step a lower voltage up to a higher voltage or step a higher voltage down to a lower one. In this case, the transformer primary has three taps: common, 208V, and 240V; you will tap a transformer to match the voltage of the power entering the transformer. Power enters a transformer through the primary. The primary and secondary windings don’t touch each other; they rely on an electromagnetic field to transfer energy from the primary to the secondary (induction). The primary and secondary are both coils of copper wire wrapped around an iron core. The ratio of wraps between the primary and secondary determines how much a transformer steps up or steps down the voltage. When there are 10x fewer wraps on the secondary winding in a transformer with 240V incoming power, the stepped-down voltage will be 24V. You may also use an ohmmeter to ohm out the primary if the transformer is de-energized and has its primary and secondary disconnected; on a step-down transformer, the resistance will be higher on the primary than on the secondary due to the greater number of wraps. The resistance will also be higher on a transformer tapped to 240V than 208V with the same secondary voltage. In the case of a failed primary, the ohmmeter would read OL. If there is a short, you will read a path between the terminals and the transformer casing. Blown fuses are commonly misdiagnosed as failed transformers. You can also measure the voltage inputs and outputs while a transformer is energized to help troubleshoot it. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this unboxing video, Bryan goes over the features and functions of the Emerson White-Rodgers All-Spark ignition module, which can replace over 1000 direct-spark and intermittent-spark modules. He also shows how to use near-field communication (NFC) to sync the module with the White-Rodgers Connect app. The NFC capabilities of the White-Rodgers Connect app don't require wi-fi or cellular data; you just link a nearby module to your mobile device and receive configuration, troubleshooting, and diagnostic resources for that module. The All-Spark module doesn't need to be turned on, either. Each All-Spark box comes with a QR code that will direct you to the White-Rodgers Connect app on your phone's app store. The app automatically configures your All-Spark module based on the part number of the OEM module you're replacing. The box comes with a cross-reference and timings booklet for manual configuration, installation instructions, the multi-connector, screws, heat shrink, terminal ends, and the fault code sticker. The All-Spark may also operate as a thermostat; it has an onboard temperature sensor and doesn't require an additional thermostat in many cases. Learn more about the Emerson White-Rodgers All-Spark at https://www.hvacrschool.com/allspark. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bert and Sam teach a class about ductless system install and maintenance practices. They particularly focus on wall-mounted mini-splits and do some flaring and cleaning prep demonstrations. When installing a ductless system, you will need to think about the placement of the head, condenser, drain, line set, and high-voltage components. Before installation, it is best to review the scope of work, make sure you have all the necessary supplies in your van, read the manufacturer's manual, determine the placement of the components, and communicate all necessary information to the customer. It is also important to have appropriate PPE for procedures like cleaning and drilling, and you'll want to make sure you don't strain yourself while you work. Flare joints are prone to leaking if we don't thoroughly test them, so we need to make sure we make flare connections that are tight and have strong copper. Make sure the copper has been deburred after being cut to avoid causing turbulence in the lines or creating ridges and cracks. You also want to use a high-quality flaring tool, whether you use a flaring block or power flaring tool; that way, the flare should have the proper diameter and depth. When torquing the flare nut, use a torque wrench set to the proper specs for the best results. All line sets should also be insulated, though some technicians have reported that some sheaths may contribute to premature leaking. Cork tape and thumb gum are also inadequate for insulating ductless line sets. Pressure testing is also critical for identifying leaks early on. You will want to coat the joints in a bubble solution, wait for a little while, and make sure you inspect each joint with a flashlight and a mirror to check for microbubbles. Vacuum practices are very similar to the best practices for traditional split A/C units and heat pumps. The decay test can also help you realize that a system has a leak. Ductless mini-splits usually have a relatively small charge compared to other types of systems. Be sure to follow the manufacturer's instructions and account for line length when setting the charge. You'll also want to make sure your condensate disposal methods are appropriate and working properly at the end of the installation. Generally, you will use either a gravity drain or a condensate pump. In many cases, gravity drains are ideal because they are quiet, have little maintenance compared to pumps, and have a lower chance of causing damage indoors. Condensate pumps may be the only feasible option when the unit is on an interior wall. When you close out an installation, be sure to explain the most important aspects of equipment and remote operation, maintenance expectations, and condensate pump noise levels to the customer. Regularly maintained ductless systems often don't take long to maintain, but they need attention to that they don't smelly and dirty quite quickly. PMs require you to talk to the customer and work inside their home, so customer service is critical. Ask the customer about their system, go over the scope of work with them, and show care for their home by wearing shoe covers and placing down drop clothes. The maintenance process can be broken down into roughly five stages: pre-inspection, communicating issues, cleaning, confirming operation non-invasively, and having a closing conversation with the customer about what you did. Before testing the system, let it run for at least 10 minutes. Then, do non-invasive testing, including checking the delta T. Watch out for things like low suction, ice on the expansion line, low split, or sloshing noises. When it comes to cleaning, you will want to pull the filters and clean them with water. Try to wash condensers with water only unless they get impacted by soil, animal hair, or other debris. You'll probably have to expose the evaporator coil, drain pan, and blower wheel. You will likely need to remove the blower wheel for cleaning. When the evaporator coil is only a little bit dirty, you might use a rag or soft bristle brush, but you may need to clean the evaporator coil in place if there is significant soil. You can clean an evaporator coil in place using a bib kit. To clean a gravity drain, flush and vacuum it and clean out the pan. You may need to remove the pan to access it. To clean a condensate pump, clean the reservoir, tubes, and screen, ensuring that the float is positioned correctly. Avoid using cleaners on pumps. To finish up a maintenance job, make sure you leave the customer's home exactly how you found it. Check the make sure the system runs as it should. Communicate everything with the customer and allow them to raise questions or concerns. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches the Kalos techs a class about Flares and Preventing Leaks on Ductless Systems, covering important tips and rules for making leak-free flares along the way. When tightening a flare nut, it’s a good idea to use a special flare wrench; flare wrenches are specifically designed to grab a flare nut and will let you tighten the flare nut without deforming it. You will, however, still need to apply the right amount of torque. Torque wrenches can be difficult to use in tight areas, so you can simply use them to check the torque and let a regular or flare-nut wrench take care of most of the tightening. A wide variety of flaring tools can be used to flare copper tubing. Although you need to deburr the copper to prevent turbulence from happening inside the tubing, you don’t want to over-ream the copper and weaken it; over-reamed copper may crack when flared. Flares should also be made in the correct size; the goal of a flare is to have a clean, smooth finish on its face with as much contact area between the face and the cone as possible. Do a visual inspection to make sure a flare is round, properly sized, and smooth before you use it. Hold the flare against the cone to verify its shape and size. The tension should go towards the connection, not away from it. So, pre-bending copper is an advantageous practice when you have to make a flare connection in a tight or tricky spot. We also put a tiny bit of Nylog on the mating surfaces, threads, and back of the flare. Although Nylog will affect the torque a little bit due to the reduced friction, it is a good practice to use an assembly lubricant as long as you know how to adjust the torque and don’t overdo it. You should thread the nut with the copper in place, as you will establish the contact at the connection. Once you tighten the flare nut, you will want to do a pressure test to ensure that there are no leaks; these pressures should be quite high. Ductless systems with hard shutoff TXVs can be tricky, as the pressures may become unequal between the high and low sides; you don’t want a differential between the high side and the low side during the pressure test because the bleeding-through action could look a bit like a leak. When you add a leak reactant to check for bubbles, you want to lay the reactant on flat, coat the flare connection, and let it sit for a substantial amount of time. The pressure test time may vary depending on the system type and size. Once you return, check for bubbles, including microfoam bubbles, using a mirror and a flashlight. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This training class gives an intro into Rack Refrigeration, particularly with a focus on market HVAC and refrigeration for facilities staff. A basic HVAC/refrigeration circuit usually has four main components: the evaporator, compressor, condenser, and metering device. The evaporator absorbs heat, and liquid refrigerant boils inside of it. The compressor significantly increases the pressure of the cool, low-pressure vapor. The condenser takes the hot, high-temperature vapor and rejects heat until it turns into a liquid. Then, the metering device drops the pressure of the warm liquid. Basic laws of thermodynamics allow the refrigerant to move heat the way it does; the core idea driving HVAC and refrigeration systems is the idea that heat moves from areas of higher temperature to lower temperature. Latent heat, which is heat that contributes to a phase change rather than a temperature change, also allows the refrigerant to absorb or reject large amounts of heat during phase changes. Once a refrigerant has become a vapor from the liquid state, its temperature can rise; the number of degrees above the saturation point is called superheat. When a refrigerant has become a liquid, its temperature can drop below saturation; we call that subcooling. All refrigerants also obey the pressure-temperature relationship, meaning that temperature and pressure rise and fall proportionally to each other. Refrigerants have their advantages and drawbacks related to their effectiveness, flammability, and toxicity. The four major components of the refrigeration circuit are connected by lines, usually the suction line, discharge line, and liquid line. The suction line carries cool superheated vapor from the evaporator to the compressor. The discharge line carries hot, high-pressure superheated vapor from the compressor to the condenser. The liquid line carries warm, high-pressure subcooled liquid from the condenser to the metering device. Some systems have additional accessories; the receiver on some refrigeration systems stores liquid refrigerant after it leaves the condenser. Sight glasses are common in refrigeration systems; instead of measuring subcooling, a refrigeration technician can look at a sight glass to ensure a full line of liquid in the liquid line. Filter driers keep solid contaminants from continuing to cycle through the system; if you start getting too much pressure drop across the drier, you'll want to consider changing it, as it might be clogged. Accumulators prevent liquid refrigerant from reaching the compressor, and they are common in HVAC and smaller refrigeration systems. Accumulators also have orifices to pick up some oil to prevent it from getting trapped at the bottom of the accumulator. In supermarkets, commercial refrigeration racks are often kept in motor rooms. These are loud, and ear protection is recommended when working on them. Motor rooms can be intimidating and appear to be small spaces, so safety is critical, and it's best to use caution when working inside them. Even though motor rooms often have exhaust fans, leaks can happen and pose a danger; technicians should leave the motor room if there is an evident leak; oil spots may indicate a leak and warrant a leak detection. Hot, exposed lines are common, so it's best to avoid touching those. The racks allow multiple compressors and evaporators to share capacity; the motor rooms usually contain compressors and suction and liquid lines. Condensers are often outdoors, and the evaporators are usually present in the grocery cases on the sales floor. Parallel racks also usually have oil return systems with reservoirs, separators, and sight glasses to manage the oil. Ice machines are special refrigeration applications that may be present in grocery stores. Makeup air units replace exhausted air in commercial HVAC systems, and they're common in spaces like kitchens to balance the pressures from the exhaust. Commercial RTUs usually bring in and condition fresh air; they may make use of economizers to assist with that fresh air mixing. Commercial refrigeration systems may contain several different controls to manage performance, including evaporator pressure regulators (EPRs), SORIT valves, pressure controls, constant cut-in controls, three-way valves, and defrost controls. Failures may occur in the main refrigeration components, and the superheat and subcooling can tell us quite a bit about the charge. In the case of superheat, we can learn how well the evaporator is being fed with refrigerant. Common compression problems include flooding and slugging, which can occur when liquid gets into the compressor. Mechanical wear and washed-out bearings can also present problems in the compressor. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This 3D video demonstrates the differences between two types of HVAC Brazing torches: oxygen-acetylene (oxyacetylene) and air-acetylene (air-swirl). Both setups can be used for HVAC brazing and soldering. The approximate temperature of an oxygen-acetylene torch at the tip is usually significantly higher than that of an air-acetylene torch. As a result, oxygen-acetylene torches heat the base metal faster than air-acetylene torches. Air-acetylene torches have a larger and broader flame, and oxy-acetylene flames tend to be more concentrated and precise. However, when using an air-acetylene torch, you must be careful because they give off more convective heat, which can damage surrounding components in the work area or cause injury. You may need a heat-blocking substance like the Refrigeration Technologies WetRag HeatShield. In general, it takes a bit longer to set up an oxygen-acetylene torch with the proper amount of oxygen and acetylene because you have to set that ratio manually. You also need to use a striker to light an oxygen-acetylene torch. Air-acetylene torches achieve the proper ratio automatically, as they draw in air and mix it with the acetylene gas. Many of these also have a sparking mechanism built into the handle. Overall, air-acetylene is less likely to burn through the tubing but more likely to cause heat damage to surrounding components. It cannot weld steel, but oxy-acetylene torches can. They have more of a wrap-around flame and tend to be less expensive than oxygen-acetylene torches, and they're often lighter because they leave you with fewer cylinders to carry (and without a pressurized oxygen tank, which can be dangerous). Overall, air-acetylene torches are best for newer technicians, and oxygen-acetylene torches work better in the hands of experienced techs in tight, concentrated areas. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bert teaches a gas furnace class. He covers components, the sequence of operations, diagnostics, and safety. Many of the concepts he covers can also apply to gas pool heaters, which we often come across in our Central Florida market. Furnaces come in multiple types. One of the more rudimentary types is the natural draft furnace, which doesn’t have an exhaust blower and relies on the rising hot air to draw in more air for open combustion. Induced draft furnaces also draw in air somewhat similarly to natural draft furnaces, but they have an inducer fan motor that pulls air in. High-efficiency condensing furnaces create their own condensation and have closed combustion. Unlike heat pumps, furnaces have fire. To create a fire, we need fuel (like natural gas or oil), oxygen, and heat. We get a flame when there is the rapid oxidation of fuel, resulting in the release of heat. Since furnaces bring fire into our customers’ homes, we need to keep safety in mind. Furnaces have many parts that are integral to proper operation. One is the inducer fan blower, which is powered by 120v and pulls in air for combustion. It also allows negative pressure to “push” air out of the exhaust. The pressure or safety switch proves that there is adequate airflow by closing under a vacuum created by the inducer blower. Limit switches are normally closed and open under abnormally high heat; you may have to reset these manually, but bimetal limit switches reset automatically. There are a few different ignition strategies, including hot-surface (HSI), intermittent-spark (ISI), and direct-spark (DS). HSI tends to be the most common, though some manufacturers still make systems with direct-spark igniters. In the Central Florida market, ISI is common on pool heaters. Gas valves, which supply the gas, are normally closed and open when 24v power is applied to the coil. The gas valve also drops gas pressure to the manifold. Flame sensors detect if there is a flame; when a flame is present, a small DC current passes from the rod to ground via the flame, and that signal gets picked up by the board. Flame sensors need to stay clean to work properly, so we should avoid touching the metal. Each part has a role in the sequence of operations. First, the furnace receives a W call on the control board from the thermostat. The control board then confirms that the pressure switch is open to ensure that the switch hasn’t failed. Then, the inducer fan starts, causing the pressure switch to close. All the while, the board checks to make sure the safety circuits are closed. Then, the ignition sequence begins; some ignition sequences have delays. Then, the gas valve opens, and the flame sensor proves the flame. Once the flame has been proven, the blower starts. Bert then demonstrates the sequence of operations on a training unit at the Kalos HQ. When getting into diagnostics, a diagnostic chart will be your best friend. It will contain error codes and a list of possible causes, as well as things to look out for when solving the problem. Furnaces need an adequate combustion air supply, and we need to look at the infrastructure to make sure there aren’t any possible pressure or venting problems that could cause dangerous conditions like carbon monoxide production or flame rollout. Some of the most common diagnostic issues include a blocked flue vent pipe, a jammed blower wheel, a damaged or loose hose, a failed inducer blower, a failed switch, loose wires, or a failed board. Limit lockout error codes are also common, and there are a number of things we should be checking, including flame rollout conditions, broken boards, loose wires, and partially blocked exhaust pipes. Failure to prove ignition is another common problem, and we have to look for issues with our gas valve, flame rod, damaged wires, and the igniter itself. Many of the same diagnostic concerns, especially regarding flame rollout and gas valve failures, are also applicable to gas pool heaters. When working on gas appliances, some of the most common safety concerns include gas leaks, carbon monoxide, and flame rollout. When someone smells gas, you should take those concerns seriously. Carbon monoxide, on the other hand, is odorless and can be a silent killer; we can reduce CO in a house by advising customers to have a heat pump installed and use a CO detector. We can also make sure the heat exchangers are in good condition—not rusted out or cracked. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bert teaches the Kalos technicians Troubleshooting & Install of a flame sensor. The flame sensor he uses in this installation video is the Emerson White-Rodgers Universal Premium Flame Sensor. You can learn more about it at https://hvacrschool.com/flamesensor. First, make sure there is no power going to the unit. To remove the old sensor, loosen the screw holding it in place. Once you remove the screw, the sensor should come right out. Check to see if it’s dirty or otherwise would benefit from being changed out. You can also use your meter from end to end to do a continuity test and check for cracks. When replacing a rod, the new one should have the same angle so that it can make contact with the flame. If you are using a universal sensor, check the manufacturer-provided charts to make sure you bend and cut the new sensor correctly. The White-Rodgers Universal Premium Flame Sensor comes with a bending sleeve so that you can bend the sensor without dirtying it with the oils of your fingers. Be sure to know how far you need to bend the rod and use the manufacturer’s instructions as a reference. Place the rod against the edge of a surface with the flange pointing up and bend it according to the chart. After you bend the rod, you can cut it if necessary. After you mount the new sensor, you can test a flame rod using the microamp scale on your meter. This test will tell you if the rod is sending a DC signal to the board; you will generally pick up between 1 and 10 microamps. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this video, Bryan teaches the Kalos techs about the things to keep out of the HVAC system. You'll want to keep water, dirt, air, solvents, copper shavings, the wrong refrigerant, and nitrogen out of the copper tubing of an operating system. We only want oil (lubricant) and the correct refrigerant inside the copper tubing of a system. However, POE and PVE oils are hygroscopic and can form acids when they interact with water, so we need to make sure there is no moisture in the system. In the Central Florida market, we push copper underground and through chases, and we have to seal the tubing shut when we do that to keep contaminants from getting into the system while we're pushing it. Pushing the copper is not a desirable installation method, as the soil can corrode the copper tubing, especially in coastal markets, and pushing copper in difficult places can cause the insulation to tear, which reduces performance. In colder markets, the oil and refrigerant can condense and pool in lower, colder areas of the tubing, which can lead to oil seals and issues when the compressor starts up. Airflow issues can make these problems worse, as the refrigerant velocity moves the oil around and is hindered by poor airflow. In many cases, you'll get solid contaminants in the system when installers aren't careful while finishing up their pipe work on the outside. If you drop something into the tubing, blow nitrogen through the other side or use a pipe wiper. Whenever we reuse copper, we make sure to use pipe-wiper tools to get rid of excess oil, moisture, and other contaminants that may have gotten into the system due to poor original installation practices. It's also important to tip the copper tubing downward while deburring or reaming and to flow a small amount of nitrogen while brazing. Other good installation practices that prevent contaminants from getting into the system include nitrogen pressure tests and pulling a deep vacuum. If you pull a vacuum on a leaky system, you're likely drawing in water vapor, which is something we want to keep out of the system. Reaming and deburring are also important, as copper burrs can cause turbulence in the lines and create leaks due to the excess friction. You'll also want to maintain your tools, especially your hoses, core remover tools, and vacuum pumps, to keep contaminants out of the system. You should be checking your tools, especially your vacuum pump, to make sure they're clean and performing their very best. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan unboxes an Emerson White-Rodgers Premium Flame Sensor and shows how to bend it. This is a universal flame sensor that can be adjusted and used for a wide range of applications. The Emerson White-Rodgers Premium Flame sensor is versatile and can work in many different appliances. It comes with a wire, a bending sleeve, and a high-temperature rod that can withstand high temperatures. It’s a universal flame sensor that replaces over 100 different parts. a Flame sensors (or rods or rectifiers) conduct a very small DC current to ground through the flame. Some electrical potential is fed from the board, and that potential is then allowed to move from the rod to ground. This process is caused by a size difference between the rod and the burner, changing the alternating current to the direct current. You can only measure that current in series, and you’ll only be able to read it in the microamp scale. Because the current is so tiny, flame rods need to stay clean. Dirty or damaged rods should be replaced with new rods when possible, as cleaning them can cause them to get scuff marks. If rods consistently get dirty, look at the quality of the flame, do a combustion analysis, and make sure there are no chemicals that might be causing premature fouling. The Emerson White-Rodgers Premium Flame Sensor comes protected and with its instructions on the top. Try to avoid touching the rod directly or damaging the ceramic. The instructions contain color-coded tables showing how you can modify the flame sensor (whether you need to bend it, cut it, do both, or leave the rod as is). To bend the rod, you will need to have an edge to brace it against. The instructions show you how to bend the rod to the degree you need. The flame sensor also comes with a screw and a bending sleeve, but it also has a 3/16” terminal in addition to the standard ¼” terminals. This flame sensor also comes with a 3-year limited warranty and works very well when paired with Emerson White-Rodgers HotRod universal ignitors. For more information about these flame sensors, please visit emerson.com/white-rodgers or the White-Rodgers mobile app. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Mike Klokus and Jeff Crable go over Kalos light commercial PM maintenance procedures. This class mostly focuses on light commercial HVAC PM best practices. First, you will want to make sure you and the customer are clear on the agreement. Then, you can start the PM with a thorough visual inspection. Lower the thermostats, test the float switches, and take copious notes about things that look concerning. Unlevel or insecure condensers are also major issues. Once you’ve done a visual inspection, you can start cleaning the condensers; your readings will reflect system performance more accurately if the condenser is clean and allowed to reach its full potential. When cleaning a condenser, try to use only water when possible; otherwise, you may need to use a safe cleaner. When cleaning microchannel coils, be especially careful about water pressure and chemical usage. RTUs may also have split coils with multiple rows; those need to be separated and cleaned. Check the electrical components of the condenser. Make sure the wires are neat and have tight connections, and make sure your readings are within their appropriate ranges. This is also the time to check the capacitor and make sure it doesn’t need to be replaced. Amp draw is another critical electrical reading. When you need to replace the electrical panel and condenser top, make sure you use all the right screws and make sure everything is secure. Then, you’ll want to check your system’s refrigerant temperatures and pressures. Check the c, subcooling, and pressures throughout the system and record those. Once you finish doing everything you need to do outdoors, go indoors and check the filter. Replace it in accordance with your agreement; in our case, we write the changeout date on the filter. We check to make sure we can safely insert and remove the filters, and we may need to present solutions to the client, even if we need to propose costly solutions like making modifications to the system if we can’t safely access, add, or remove the filter. Do another visual inspection at the air handler, paying special attention to blower wheel cleanliness, panel insulation, and wire routing and connections. You’ll also want to clean the drain pan; whatever is in the pan will eventually find its way into the drain line, so the pan MUST be cleared of any debris. When cleaning drain pans, you’ll want to run water through the pan and the drain until the water is completely clear. When cleaning the evaporator, we want to try to stick with water or self-rinse cleaners. We want to make sure that we use very mild chemicals, and any foaming cleaners should be diluted appropriately and rinsed entirely. In some cases, we may need to pull and clean the blower wheel; you can quote for this if it isn’t in your agreement. In some cases, you may have to clean a condensate pump or a common drain. The common drain is often the responsibility of the plumber; HVAC technicians should definitely clean the drain leading to the common drain, though. However, you need to know where the common drain leads, so be sure you know where it goes before you use compressed air or cleaners to flush the drain. HVAC technicians do, however, have to clean condensate pumps on PMs. Also, check for double traps and to make sure that the drain lines are properly pitched, trapped, and vented; vents should be uncapped, but cleanouts must be capped. It’s also a good idea to check the float switches, especially if you have multiple; multiple float switches should be wired in series. At the end, make sure you fill the trap. Some of the units may have heat strips; we test these during our fall PMs. You just have to be mindful of possible smoking as the dust burns, and you may have to clean those manually before testing them. When you finish a job, make sure you leave the site exactly as the contract states. Some customers may have specific requests for thermostat settings, so you must heed those. Do a final inspection, make sure all disconnects are back in, clean up all trash and tools, and share any notes with the customer. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This 3D video demonstrates how we do oxy-acetylene brazing for residential HVAC equipment. We show how to braze copper at both the air handler and the outdoor unit, and we cover some considerations when brazing and soldering other metals. Start by removing Schrader cores, which can cause pressure to build up in the system when you flow nitrogen. If you’re working on a system that already has refrigerant in it, you will need to use proper recovery practices. Before cutting copper, be sure to clean it. Then, ream or deburr the copper tubing to remove the burr. Cutting copper causes a burr to form on the rim of the tubing, which can cause turbulence or deform your flared connections if it stays in the tube. Make sure the burr doesn’t fall in and that you don’t over-ream your copper. Fit the tubing together and ensure that there isn’t too much of a gap between the male and female ends. If the gap is too large, you risk making a weak connection and ought to consider using reducers or bushings. First, purge the air from the system with nitrogen. Then, flow nitrogen at 3-5 SCFH, which is a very tiny amount. Before brazing, make sure you have your PPE and a fire extinguisher. Protect components with a wet rag or a heat-blocking putty, like Refrigeration Technologies WetRag. Your oxy-acetylene torch rig should NOT have any oil on the threads. First, connect the oxygen regulator to the oxygen tank, and then do the same for the acetylene tank. Connect and tighten your hoses to the regulator and torch handle assembly. Make sure you use the appropriate torch tip, including specialty tips in special applications. Then, close off the regulator adjustments and open the tanks. Bubble-test the connections and hoses to check for leaks in your torch rig. Set the pressure at the regulator with open torch handles, which may vary. Use a proper striker to light the torch; you may light it with acetylene first or with oxygen and acetylene already mixed. You will want a flame that’s as close to neutral as possible. Carburizing flames have large secondary feathers and have too much acetylene, and oxidizing flames have no secondary feathers and have too much oxygen. Heat your copper to a dark cherry red color, moving your torch to conduct heat into the joint. That will allow the alloy to be drawn into the joint. You’ll want to make sure you’re flowing nitrogen when you’re brazing copper, as cupric or copper oxide can build up on the inside otherwise. When you’ve finished, shut off oxygen first and then acetylene. In the field, you might shut them off simultaneously as quickly as possible. Copper is the most common brazing metal, and it can be annealed. It’s also easy to estimate its temperature by color, and it can be fluxed with phosphorus-bearing alloys. However, some “copper” components are actually copper-plated steel, so you have to treat those components as steel when you reach the steel. Brass is softer and often used for cast parts like valves. It has a lower melting temperature and doesn’t conduct heat as well as copper. It’s best to use a high-silver rod with a paste flux (or a flux-coated high-silver rod). Steel is common in compressor stubs. When working with steel, avoid phosphorus-bearing rods. Stick with a high-silver flux-coated rod or a high-silver rod with a paste flux. Aluminum has a low melting temperature and doesn’t give you temperature indicators, so it can be tricky. You will also not use the same alloys or flux you’d use for the other metals. Usually, the flux will be your temperature indicator. When patching an evaporator coil, you will have to solder aluminum. It’s a good idea to use an air-acetylene torch or MAPP gas torch. Repairs can be done within the coil pack or on the U-bends. Heat the tip of your rod and dip it in the flux. Heat the base material and melt the flux on top of it. Heat the flux until it goes clear and quiet, add the alloy, heat the alloy until it goes clear and quiet, and then pull the torch back. Then, clean off the flux to prevent corrosion. You can also use an indirect heating method with a separate flux. Heat the base material, apply the flux, heat the flux until it bubbles, and back off and apply the alloy. Pressure-test and bubble-test your system to check for leaks. When you’ve finished brazing, allow your connections to cool for a bit before cooling them with a wet rag. Inspect your connections with a mirror. If everything looks good, you can add your core remover tools and do your pressure and bubble test in preparation for your vacuum. Again, check your connections with a mirror. You don’t want to see bubbles or microfoam, and you don’t want a pressure drop. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This video is Bryan’s full-length electrical basics class for the Kalos technicians. He covers electrical theory and circuit basics. Volts, resistance, and amps all affect the behavior of electricity in circuits. These are also critical factors in electrical safety. Watts and kilowatts come from the multiplication of the volts and amps, though not every volt-amp does work; the power factor indicates how much work the volt-amps are actually doing. Some of the volt-amps are reactive (kVAR) and don’t do the real power of watts. Electrons move by interacting with other atoms. Substances can be conductors or insulators, and conductors have very few valence electrons, which move in and out of other atoms easily. Insulators have many valence electrons and are more stable. Insulators have high resistance, and conductors tend to have low resistance. Circuits consist of loads, switches, and power supplies. Loads actually do things and consist of light bulbs and motors. Switches pass power and don’t do work. Power supplies can be finite, like batteries, but also include transformers that take power from the utility company. Open circuits don’t move electricity, but closed circuits create a complete path that allows electrons to move. Electricity takes all available paths, not just the path of least resistance. Bryan also covers: Electricity and the body GFCIs and AFCIs Shock and arc flash protection Lockout/tagout Electricity and fall hazards Energy transfer Resistive vs. inductive loads Magnetism and flux Direct current (DC) vs. alternating current (AC) How power companies and generators work Open vs. short circuits “Path of least resistance” Tripping breakers Electrical units of measurement Step-up and step-down transformers Electrical frequency (hertz) Variable frequency drives (VFDs) Microfarads and capacitors Parallel and series circuits Becoming more proficient at reading diagrams Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This video is Bryan’s full-length electrical basics class for the Kalos technicians. He covers electrical theory and circuit basics. Volts, resistance, and amps all affect the behavior of electricity in circuits. These are also critical factors in electrical safety. Watts and kilowatts come from the multiplication of the volts and amps, though not every volt-amp does work; the power factor indicates how much work the volt-amps are actually doing. Some of the volt-amps are reactive (kVAR) and don’t do the real power of watts. Electrons move by interacting with other atoms. Substances can be conductors or insulators, and conductors have very few valence electrons, which move in and out of other atoms easily. Insulators have many valence electrons and are more stable. Insulators have high resistance, and conductors tend to have low resistance. Circuits consist of loads, switches, and power supplies. Loads actually do things and consist of light bulbs and motors. Switches pass power and don’t do work. Power supplies can be finite, like batteries, but also include transformers that take power from the utility company. Open circuits don’t move electricity, but closed circuits create a complete path that allows electrons to move. Electricity takes all available paths, not just the path of least resistance. Bryan also covers: Electricity and the body GFCIs and AFCIs Shock and arc flash protection Lockout/tagout Electricity and fall hazards Energy transfer Resistive vs. inductive loads Magnetism and flux Direct current (DC) vs. alternating current (AC) How power companies and generators work Open vs. short circuits “Path of least resistance” Tripping breakers Electrical units of measurement Step-up and step-down transformers Electrical frequency (hertz) Variable frequency drives (VFDs) Microfarads and capacitors Parallel and series circuits Becoming more proficient at reading diagrams Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Jesse Claerbout, VP of mechanical operations at Kalos Services, teaches a class about negotiating with vendors. A vendor is NOT the manufacturer of equipment; vendors merely purchase, receive, and locally distribute equipment from manufacturers. Vendors are not responsible for equipment quality, pricing trends, warranty guidelines, or the supply chain. They can, however, control the products they choose to carry and the markup on products from the manufacturer. Contractors need to rely on vendors to make their jobs easier, as vendors are the ones who make equipment and materials easily accessible. It would benefit the contractor to have some traits that are attractive to vendors. Attractive contractors will have more negotiating power than those who aren’t. Contractors that have a high volume of sales are attractive because they can help the vendors to move as many products off the shelves as possible. The vendor’s goal is to move boxes, so they want to work with contractors who will buy or rent lots of equipment from them. Consistent, reliable payment history is also a must on the contractor’s side. To respect vendors, we must understand what they do and their challenges and responsibilities. When contractors respect vendors, deliver on promises, and have mutual goals, vendors will be more likely to go the extra mile for those contractors. Having respect for vendors doesn’t mean reducing your standards of service; you might just need to show some compassion and be willing to work with vendors. Vendors will also be more willing to do their best for contractors who develop strong relationships with them. When identifying potential new vendors, contractors ought to consider if a vendor is within their service area, has the right product mix, and has competitive prices. The vendor’s business model should also be consistent with the contractor’s. Contractors should consider is they become priority customers if they start a relationship with a vendor; they need to be able to bring enough to the table to make a vendor prioritize them. It would also be wise to steer clear of vendors who have a poor reputation. Communication can help us identify ideal vendors. We can prevent many conflicts if we provide clear dates as to when we will need certain products. It’s also worth noting that vendors should make a profit. However, contractors should be skeptical when vendors claim the inflation excuse when they hike up their prices but rake in much larger profits than normal. Vendors must make money, but it should not happen at the contractor’s expense, which can happen if contractors don’t negotiate the pricing. Negotiating is not easy, and it may require approval from leaders in your contracting business. To negotiate with vendors, you need to set aside time to have meetings and conversations. These can happen once a year or once every couple of years. These conversations are critical to have with potential new vendors as well. You’ll want to see if those new vendors are competitive, and if they give you a competitive price, you can use that as a starting point for negotiations with current vendors. If you need to negotiate with vendors, you need to know your products and who you’re talking to. Some people may not be qualified to change the pricing, or they might not be as knowledgeable as someone higher up in the vendor’s company. It’s also great to ask the vendor questions if you don’t understand their pricing choices. You also want to be smart when considering the perks; discounts are worth a lot more to the business than a golf trip or free donuts. Go into negotiations knowing your budget and numbers so that you can make evidence-based decisions and introduce facts to the discussion instead of making promises that you might not be able to keep. You need to know if your contracting company can bring value to the vendor and what that value would look like for the vendor. If you become close with a vendor, then you must be careful about their prices and not excuse price hikes that happen after rewards like fishing trips or golf trips. When contractors get good pricing and can save on materials, it enables them to invest in vehicles, employee compensation, and bonuses. Discounts add up and are definitely worth negotiating with vendors. Vendor relationships should be win-win situations, and it’s possible to respect the vendor and maintain a good relationship while keeping the company’s own needs in mind. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Good news! Another video w/ Bert. He finds a breaker tripping periodically in the field and has reason to believe that it's a case of the breaker overheating. He explains how to diagnose and repair that type of situation. If you find a point of high temperature in an electrical circuit, keep in mind that those are points of resistance. Those single points don't cause the entire circuit to overheat. However, undersized wires have higher temperatures over a length of space, and the heat is a bit more widespread. Overheating happens where the increased resistance is, but that doesn't increase the overall current of a circuit. The voltage drops, and there's less current overall in the entire circuit. When a breaker trips periodically, Bert checks for poor connections due to loose or corroded connections. In those cases, the amp draw may be normal, but the wires will run hot, and the breaker will pick up heat. Bert removes the breaker and checks connection points; in this case, he notices discoloration on one side. That indicates a loose connection or a pitted contactor, both of which cause overheating and intermittent breaker tripping. Only licensed electricians should do work on electrical components like breakers; the Kalos techs are licensed electricians and can do that type of work inside panels. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan and the Kalos techs talk about head trash and how it prevents us from being the best HVAC professionals we could possibly be. Sometimes, saying that something is "easy" or "straightforward" can create head trash; if you struggle with a task that someone else calls "easy" or "straightforward," you could start to think that a person doesn't care or that they're trying to pick on you. When undesirable things happen to us because of interactions with our leaders, dispatchers, or fellow technicians, we all too often start building unproductive narratives about those people. Those narratives can spiral out of control and draw in lots of negativity. When we read into people's motives (especially unfavorably), we forget the facts. We assume so much, but we often don't realize how little people often think about us. It's a good idea to take out that "head trash" so that it doesn't keep piling up and turning us into negative, unproductive people. Sometimes, we need to have conversations to establish that we're on good terms with others, and that's okay; it could help us get rid of that head trash. Managing your expectations is a good way to stop head trash from building up. That can go for our personal lives and our professional lives. Set expectations in a way that avoids disappointment and over-promising. That way, you can prevent head trash from forming in your head or others' heads. In the end, we all just really want growth. Head trash gets in the way of that, and it's up to us to keep our head trash in check and check in with people when we're not sure where they stand with us. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches the Kalos apprentices about electrical current (amperage). He covers some basic electrical theory and troubleshooting practices that may require you to measure amperage in the field. Current, not to be confused with “power,” refers to the movement of electrons in an electrical circuit. Electrons don’t “flow” through a circuit like water through pipes, but they behave more like little forcefields, which is what does the work and is picked up by the amp clamp of a multimeter or ammeter. Voltage, on the other hand, is like a source of electrical pressure. The more voltage behind a current, the stronger the field. There needs to be electron motion for there to be current; voltage doesn’t necessarily indicate the presence of current. Voltage and current make up Ohm’s law, which states that voltage is equal to the multiplication of current and resistance. In other words, current increases as resistance decreases and vice versa. If you’re verifying that a system is off, you’ll clearly want to measure voltage with the equipment off; however, you’ll want to measure voltage under load if you’re checking equipment operation. If you’re working on a conductor and notice that the current is higher than it’s supposed to be with normal voltage, then the resistance is low. That could happen because the windings or conductors touch another surface and make an undesigned path. We call those situations “shorts.” To make this concept easier to understand, Bryan uses a traffic analogy; a highway with potholes will make it harder for cars to pass through, but an exit that allows traffic to bypass the slower path on a superhighway and move a lot more cars. That superhighway behaves like a short. High amperage should cause breakers to trip or fuses to blow. In the case of a thermostat, the R terminal has a path in, Y has a path out, and there is a contactor coil. Then, that contactor coil connects back to C, common. When the contacts close, current may flow; your amp clamp should read roughly the same amperage at all points on the conductor. Contactors that don’t pull in properly could draw higher current than normal. Also, the amperage along the conductor should match the current inside the thermostat; the temperature could rise if another component of the low-voltage circuit is drawing higher current than normal. So, a failed thermostat could be caused by higher current elsewhere in the circuit, To get a proper amperage measurement, you will want to make sure you center it inside the amp clamp. If the conductor is too close to the edge of the jaws, you could read a higher amperage than what’s really there. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Pierre and Cameron talk about lockout/tagout procedures, also known as LOTO. They also demonstrate the procedures in action. LOTO is an OSHA-mandated way to control hazardous energy sources. There are 8 main steps to the LOTO procedure. The first step is to notify affected employees that the equipment will be shut down and undergoing repairs or maintenance. Next, you want to identify the procedures and hazards of the work, especially because the hazards can vary across electrical, hydraulic, or thermal energy sources. Hazards can also vary in their magnitude and the way they can be controlled. The third step is to shut down the equipment and isolate the energy source from the machine, keeping in mind the equipment hazards, components, and shutdown procedures. Verify that the power is off. Then, you apply your LOTO devices. LOTO devices consist of locks or tags. In cases where you apply a physical lock, the idea is that nobody can open it without the key—and only the person(s) working on the equipment should have the key(s). These locks can vary, consisting of traditional locks and straight-line locks with bits at the end. When you’re working on machines with multiple circuits, you may have to lock out more than one point. It’s also a good idea to have written instructions and records related to lockouts so that superintendents and other people on the job site understand what to do during a lockout/tagout situation and why it’s going on. You must also tag out the equipment to notify people in the area that someone is working on the equipment. Tags should also include the name of the person(s) who locked or tagged the equipment out. These tags often explain why the equipment is being shut off and when normal operation can be expected to resume. After locking/tagging the equipment out, you will want to verify that all stored energy has been released. In electrical systems, you want to make sure that there is no voltage behind the system. Other systems could have pressurized contents that could cause injury, so that blanket term covers hydraulic, thermal, etc., systems. In the case of electrical systems, you will want to check for voltage from leg to leg and from leg to ground. The equipment should also not turn on once the power has been isolated. Once you’ve verified that stored energy has been released, you will also want to ensure that you have an arc flash kit and a fire extinguisher at your disposal. (ABC fire extinguishers are standard for general use, though electrical fire extinguishers can be good for electrical applications.) Arc flash kits include a face shield, safety glasses, safety gloves, and fire-resistant clothing. When it’s finally time to bring the equipment back online after you’ve done your repair or maintenance procedure, you will want to start by clearing the area. Once you remove the LOTO kit, you can bring the breakers back on and then re-energize the equipment. Then, once you successfully start the equipment up again, verify that the machine or system is working properly. Over time, LOTO procedures may change. OSHA provides the main framework for LOTO, but individual companies can adjust procedures that aren’t explicitly provided by OSHA. It’s the responsibility of company leaders to communicate changes to the company policies, reinforce the rules in place, ensure that workers have the proper PPE, and call out improper use of LOTO. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Kalos leaders Dan Riggs and Nathan Orr explain some rooftop unit (RTU) install best practices and talk about some common changeout considerations. Rooftop units, or RTUs, are commercial HVAC units and may sometimes be called "package units" when the application is on the ground. When installing or changing out an RTU, you need to think about the unit's size (including weight), the area around the unit, adapters or curbs, orientation, climate conditions, duct configuration, and if the unit requires reheat. In many cases, you'll need a crane to get RTUs on top of buildings. To operate a crane, you'll need to know the basics of rigging and signaling. Rigging refers to the connection of a load to a crane, and signaling refers to the process of controlling a crane with visual gestures or audio cues. When rigging, you want to try to minimize damage to the unit, especially by doing close visual inspections throughout the process. Certification is often required for rigging and signaling. When thinking about crane picks, location is perhaps the top concern; you don't want cranes to stand over grease traps, drainage, soft ground, uneven terrain, or other potentially catastrophic areas. Some areas may require permits or further consideration, including near power lines or trees, too close to airports or runways (you may need a permit), or inside a structure. You'll also want to consider the weight of your load (plus the rigging) and the crane's distance from the load. Weather (especially high winds) and the need for a spreader bar are other things to keep in mind. Commercial units may be subject to ventilation standards, so we need to size units for the appropriate fresh air intake to hit the required air changes per hour. In our market, a common assumption is that there should be one building occupant per 200 square feet, and 17 CFM of outdoor air is required per occupant. In some cases, you may have to consider the effects of economizers, exhaust fans, vestibules, and makeup air units on the fresh air intake, air mixing, and air pressure. There must also be sufficient distance between fresh air intakes and exhaust structures. Cooling towers also introduce humidity and should be placed away from fresh air intakes to prevent the fresh air from picking up extra moisture. Intake openings should also not be positioned near lot lines or other buildings on the same lot. The electrical side of RTU installation also requires a lot of thought. For example, on changeouts, you'll have to determine if existing wires and breakers meet the correct sizing requirements per the MCA and MOCP. If you change the unit's orientation during the changeout, you also have to make sure your wires can reach their new location. You may also have to weatherproof electrical penetrations and extensions to prevent moisture from posing a hazard to the electrical equipment. When thinking about condensate drainage, you must consider the unit's tonnage, roof pitch, putting in an appropriately sized and placed trap and air gap, and the drain pipe material (especially. The diameter should be at least 3/4" and no smaller than the drain pan outlet diameter, and the slope should be at least 1/8" of fall for every foot of horizontal run (1%). Drains also need to discharge to different types of areas depending on what they may contain; for example, drains that may contain oils may need to drain into a grassy area instead of a gutter. Tie-down specifications also matter, especially in windy or hurricane-prone climates. These specs may vary wildly based on location, but the ultimate goal is to keep the RTUs from coming off the buildings in extreme weather. Curbs allow you to affix an RTU to a building. In changeout scenarios, you may either need to introduce a new flat curb or install an adapter to the existing curb. Flat curbs typically connect the RTU to the building envelope, not supported by the roofing material. Curbs must also be leveled properly so that the RTUs can drain appropriately, so you may have to shim the curbs. If you decide to use an adapter with an existing curb, you'll have to keep in mind that the specs will usually be customized, though the manufacturer can often help you out. The curb, however, is usually NOT custom-made, and that's what we need to pay attention to. You also can't install adapters to other adapters or shim the adapters. Minimum steel requirements are usually the points where the peak load at first concrete cracking matches the ultimate load after steel yielding. In other words, the steel must support the load but not overload the concrete. Steel reinforcement must be done thoughtfully with careful attention to curbs, adapters, etc. The supply and return dimensions refer to the outlet and inlet sizes of an RTU. You must ensure that curb submittals take these dimensions and duct sizing into account. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches the Kalos technicians how to troubleshoot locked compressors in an HVAC system. He also talks about the appropriate usage of aftermarket and factory hard start kits. Although the compressor is the main focus, you can apply some of the practices to other types of motors inside an HVAC system. A locked compressor typically draws locked rotor amps for a short period of time. The rotor rotates around the stator, and a “locked” rotor draws higher current and doesn’t spin. In those cases, the resistance (inductive reactance) is lower, resulting in a higher current. Inductive loads produce back EMF at the beginning and create inductive reactance, which is why you see higher current at the start and higher resistance later on. That differs from a resistive load in which the resistance stays fixed. When the windings don’t have that resistance, they become hot and set off existing overload safeties. Locked compressors often overheat due to the hot windings. However, overheating may also happen due to an undercharged system, which is an operational overload. Operational overloads, including conditions that result in high compression ratios, tend to heat up the entire compressor more than the windings. Locked rotor amps, by themselves, don’t usually produce particularly useful measurements when it comes to troubleshooting. In some cases, we might be able to stop a compressor from locking by adding a hard start kit. However, we should first verify that the capacitor is performing well, that we have sufficient incoming voltage, and that the system has been wired properly before resorting to a hard start kit. If a new system has a locked compressor but works with a hard start kit, then we can diagnose the issue (under-voltage, long line sets, etc.). Sometimes, we can use a factory hard start kit permanently, especially if the manufacturer specifies so. In many cases, it’s better to get a factory hard start kit than rely on an aftermarket hard start kit for a long time. Aftermarket start kits are designed to work for a wide range of compressors, whereas factory hard start kits are tailored to specific systems and can take the start capacitor out of the circuit at a more appropriate time. You may need to look at the system warranty to see if a factory hard start kit is worth adding or if an aftermarket hard start kit is good enough to keep an old unit running a bit longer. It’s worth noting that hard starts are NOT the same as soft starts, which modulate current into the compressor and produce more of a gradual startup than an immediate start with a current spike. Soft starts work well with systems that rely on generators or solar power. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan and Eli show off the battery-powered BreakFree® Power Tube Expander by NAVAC (NTE11L). The BreakFree® Power Tube Expander won gold in the Hand Tools category of the Dealer Design Awards because it's fast, long-lasting, and compact, and it lets you make perfect swaged fittings in the field. You can use the BreakFree® Power Tube Expander on copper lines between 3/8" and 1 1/8" in diameter. The tool also comes with instructions right on the side, which lets you know that you can only use it with soft or annealed copper, copper must be reamed or deburred, operation can be stopped at any time by pressing the sole button on the tool, and you can reset the tool at any time by pushing the slider forward. The battery is also long-lasting, meaning you can get many uses out of the tool before you need to recharge it, and the tool also has a battery life indicator to let you know roughly how much longer you can use the tool before you need to recharge it. This tool makes swaging very easy in the field, and it comes with a light to help you see the copper tubing in dark places or at night. To use the tool, merely ream or deburr your copper, insert the expander head into the copper, press the button, and hold the copper in place. The tool will expand the tubing and stop automatically once it has finished. You can get the NTE11L at many supply houses or order it online at https://www.trutechtools.com/navac-nte11l-breakfree-power-tube-expander-kit.html. Be sure to use the code GETSCHOOLED at checkout for a discount! Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches the Kalos techs a few more callback prevention tips. This time, he focuses on some specific installation, commissioning, and technical practices that reduce the likelihood of receiving callbacks. When it comes to brazing, you have to use enough heat to draw the alloy into the joint, but you don’t want to use too much, either. If you braze too long or use too much heat, you could end up burning surfaces or components. You can avoid burning components in the work area by using a heat shield. An air-acetylene torch has a larger heat area, but it has a more convective flame than an oxy-acetylene flame; the actual flame isn’t as hot, but the area around the flame tends to be hotter. In any case, you will want to heat the joint to a dark cherry red color, not bright red, and apply the brain rod. To protect heat-sensitive components, use a wet towel or a heat-blocking putty, like Refrigeration Technologies WetRag. Thorough leak detections also prevent callbacks. Start with a visual inspection, using a mirror to check all the joints. Then, pressurize the lines with nitrogen and apply a leak reactant (bubbles) to the joints and look for microbubbles. Follow up with a nitrogen pressure test lasting at least 20 minutes (though longer is better). Make sure to remember your starting pressure to get an accurate idea of the PSI drop. Once you’ve done your pressure test, pull a deep vacuum. If you can, pull below 300 microns; use large hoses and pull your cores to get a deeper vacuum. Then, valve off at the core tool and do the decay test. The system should not decay to 500+ microns in 10 minutes, though there may be some variation depending on system conditions. A failed decay test may indicate a leak. You will also get different decay rates when you use a one-hose evacuation instead of a two-hose evacuation because the methods cause different rates of equalization. Sound, sensible system infrastructure will also help prevent callbacks. You need the drain line and system to be placed far enough away from each other (about 2 feet), and the system should be away from walls or shrubbery. If you have to use long line sets, you need to make sure you charge the system appropriately; you can use the long line calculator on the HVAC School app. To ensure that you have the proper refrigerant charge, try to use non-invasive testing to minimize losses through hoses. Make sure the superheat and subcooling are within appropriate ranges for the system. If you have to add or recover refrigerant, make sure you use a scale to know how much refrigerant you’re adding or removing from the system. If a system is low on charge, fit a leak detection into your quote to prevent future heartbreak. Drains are also common reasons for callbacks. We need to make sure that the drains are clean and properly pitched (at least ⅛” of fall for every foot of horizontal run). Bacterial zoogloea cases need to be resolved, as those can cause recurring problems in systems with all-aluminum coils. Drains also shouldn’t have double traps, and cleanouts and vents should be accessible. When cleaning a drain, be mindful of toxic chemicals, and handle those carefully. If you use a cleaner, flush the drain with a lot of water. Although some callbacks happen due to exotic system problems, many callbacks can be prevented by being thorough when brazing, doing pressure tests, pulling a vacuum, and cleaning drains. Learn more about Refrigeration Technologies products at https://www.refrigtech.com/. Learn more about Asurity Pro-Treat Line Guard at https://www.diversitech.com/en-US/item/maintenance-chemicals/pan-treatments/disinfectants/pro-treat%C2%AE-pan-strips--PTLG-100. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan shows installation and testing the Emerson White-Rodgers SureSwitch (49M11-843) Step by Step. The SureSwitch is a multi-voltage contactor that can replace a wide range of OEM contactors for 24v, 120v, 208v, and 240v applications. Before installing the SureSwitch, disconnect the power. Then, confirm that the power is off by checking the voltage from leg to leg and from leg to ground. Once you’ve confirmed that there is no power, use the diagram on the SureSwitch to determine which contacts you will use. Cover the unused contact. Remove the old contactor and begin mounting the SureSwitch, attempting to use existing holes. Wire in the contactor using the two uncapped contacts. With the contactor coil in place, connect your line and load power according to the sticker on the SureSwitch. Then, use a torque wrench set to the correct specifications to torque your wires according to their size and the sizing chart on the SureSwitch. Once you have wired and torqued the connections, you may reinsert the disconnect and restore power to test the SureSwitch. Keep in mind that the SureSwitch is energized by line voltage in addition to the 24v power. The rapid flashing light indicates a start delay, and a solid light indicates that the SureSwitch is fully operating. Check the voltage to confirm that you have the appropriate line voltage. Then, check the compressor and condenser fan motor amperages. Use the 5-second test mode by pressing and holding the “test” button for one second. Once you have confirmed that the SureSwitch is operational, apply the aftermarket sticker to a blank spot within the electrical panel. To get an idea of the cycle count, press and hold the “count” button. Each flash count and color corresponds to 10,000, 1,000, or 10 cycles. Add up the corresponding flashes to get the number of cycles. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this Kalos Leadership meeting, Kalos founders Robert Orr, Keith Huntington, and Bryan Orr talk about planning and executing projects. Kalos is an HVAC business, but it also focuses on commercial refrigeration, electrical, and construction projects. In the early days of the company, the founders settled on the name "Kalos" because it means ''integrity'' in Greek. The principles behind the name have set the tone for Kalos's practices in its HVAC, electrical, refrigeration, and construction projects. Overall, the Kalos business model is about being up-front about pricing, doing the very best work possible, and treating others how we'd like to be treated. All of those things establish positive relationships and set expectations. The Kalos vision for the future focuses on communication and continuous improvement. Kalos wants to give its employees room to grow and allow them to establish a good work-life balance. As employees experience growth in their personal and professional lives, Kalos can do better work. When doing construction projects, it's important that the projects are completed on time, stick to the budget, and satisfy the customers. Those things make up the project mission, which is the priority of the project leader and superintendent. The best project leaders and superintendents don't accept excuses and ensure the project is seen through and done right. They also examine the context and data surrounding a project to plan and execute the project mission. Wide-narrow-wide thinking, which we apply in troubleshooting, also applies to planning and strategizing construction projects; strategies and plans require tradespeople to consider the big picture and the details. To plan a project, Robert and Keith consider the entire site. The drawings often don't represent the reality of the site, so we need to catch inconsistencies and anticipate issues before they occur. To do that, the founders build the projects in their head as they factor in the job specifications and challenges with the location, including obstructed areas, heavily populated spaces, and places without drainage. Asking questions early and getting the labor, materials, and equipment prepared from the beginning are also key factors of successful projects. Once all preparations are in place, project leaders can lay out the tasks and objectives for each day. Everyone has a role in determining a project's outcome, not just the leaders. Trainees and apprentices can do their part during the execution phase by arriving on time and being ready to begin working. Following directions, learning how to read plans, and keeping the work area clean and safe are also critical responsibilities for trainees and apprentices. Reading plans and specs will come naturally with practice; a single class on reading plans likely won't prove useful without an outside commitment to keep learning. Taking correction readily is another key to success. Tradespeople and journeymen can also contribute to a project meaningfully by arriving on time and ready to work, applying best practices, and following plans and specs. They can also communicate with leadership to ask questions and request clarification as needed to do the best possible job. Foremen and superintendents can execute a job well by making the tradespeople and journeymen commit to the job. They can achieve that by arriving with a clear plan for the day, enforcing best practices, and navigating issues that the tradespeople and journeymen might not see. They communicate clearly and constructively, set firm requirements, and follow up with their team and the customer. The founders also discuss the best tools for planning and communication, including Loom, Google Calendar, Trello, and others that have made Kalos operations run smoothly for years. Loom videos are great for communicating within an organization. Google Calendar is great for keeping track of events and deadlines in your personal and professional life. Trello also allows you to track the progress of a project. You have to give these platforms special attention and follow up with people while you use them to make sure your communication is clear and to prevent team members from making excuses. Good project leaders know how to keep their teams doing their best work and offer specific praise and credit where it is due. They know how to get engaged early and have productive conversations to prevent issues before they start. It's everyone's job, however, to stay engaged and resolve interpersonal conflicts with humility. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this unboxing video w/ SureSwitch, Bryan gives us a look at the Emerson White-Rodgers SureSwitch (49M11-843) and explains why this is a contactor upgraded. He also shows us what the multi-volt contactor comes with and how it works. The multi-voltage nature of the SureSwitch allows it to be used as a contactor for 24v, 120v, 208v, and 240v applications. So, the SureSwitch can be used for a wide range of residential, commercial, and refrigeration equipment. It has a 1+ pole connection, meaning it has one contact and one connect-through pole. The SureSwitch has up to 5x the life expectancy of a typical contactor, partially because it has a sealed switch that prevents insects from getting inside. It also has integrated compressor protection for conditions like brownouts and short cycles, and it can replace many types of OEM contactors. The SureSwitch comes with a sticker that you can place on the electrical panel. This sticker contains guides for equipment testing and flash codes. It primarily exists to notify future technicians that the contactor is NOT an OEM type. “Load out” and “line in” are clearly indicated on the contactor out of the box. The control coil comes with different connections based on the line voltage, mounting screws, and a terminal multiplier flag terminal (for multiple connections). The SureSwitch has a random start delay to prevent current spikes in applications with multiple SureSwitch contactors (such as multi-family residences). You can run a 5-second compression test by pressing the “test” button for one second. To get an idea of the cycle count, press and hold the “count” button. Compared to a regular contactor, the line and load connections are relatively close together (as opposed to on opposite sides). Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan explains why you would measure discharge line temperature. He goes over the information that you could learn from discharge line readings and how to reduce excessive discharge line temperatures and compression ratios. The discharge line is the smaller line that exits the compressor and eventually feeds into the condenser. On a heat pump, it normally goes into the reversing valve from the top. The discharge line should not be confused with the liquid line, which goes out of the condenser. You can expect the discharge line pressure to be a bit higher than the liquid line pressure, but its temperature will be way higher than the liquid line temperature. That’s because the condenser desuperheats that very hot vapor, condenses it to a liquid, and cools it below the saturation temperature (subcooling). Like the suction line, the discharge line contains superheated vapor. However, the temperature of the discharge line is much, much higher than that of the suction line. You can use Bluetooth probes to measure the discharge line. Several things impact the discharge line temperature, including the location. Normally, we want to measure the discharge line temperature about six inches away from the compressor; the temperature can vary quite a bit depending on where we take our measurements, so the industry standard is typically lower than 225 degrees six inches from the compressor outlet. However, individual units may have higher or lower specifications. (The compressor may be around 70 degrees hotter, and the area near the condenser will be significantly cooler.) Normally, when the compressor exceeds 300 degrees, oil breakdown may occur. Higher temperatures result in oil with reduced viscosity, meaning the oil becomes thinner and cannot lubricate the bearings as well as it should. Mechanical wear in the compression chamber is another problem that can be discovered by finding a high discharge line temperature. So, we want to run compressors as cool as possible. High compression ratios may cause compressors to overheat. So, we want to do whatever is in our power to reduce the compression ratio. We can find the compression ratio by dividing the absolute head pressure by the absolute suction pressure, and we typically want that quotient to be ~3 for modern air conditioning equipment (refrigeration equipment tends to have higher compression ratios). We can reduce compression ratios by keeping the compressor cooler, such as by using interstage cooling or liquid or vapor injection to reduce discharge temperatures. Dirty condensers that restrict airflow also raise the head pressure, increasing the compression ratio and resulting in higher discharge pressures. Significantly overcharged systems may also raise head pressure. Low suction pressure also leads to higher compression ratios; low suction pressure may be caused by low loads or metering devices that feed the evaporator coil poorly. However, cooler suction lines don’t necessarily cause the discharge line to be cooler, especially if the mass flow rate is also low. Copeland Mobile can show you how operating a system outside its operating envelope can contribute to poor system performance (assuming you’re working with a Copeland compressor). You can adjust the conditions within the app to see what the discharge temperature, compressor capacity, and mass flow rate will be under various operating conditions. You may find it exceptionally helpful when used with the AE Bulletins app, which contains useful information about Copeland compressors. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches a class about callback prevention with an emphasis on communication and priorities during service calls. Callbacks aren't profitable, and they're often a source of frustration for customers as well as techs, so our goal is to avoid them. Whenever a customer calls us back a short time after the last service (within ~30 days), that classifies as a callback. In many cases, callbacks happen because of miscommunication; often, the customers don't have realistic expectations for the system. So, thorough communication can prevent many callbacks. Customers should feel like their concerns and complaints have been heard and acknowledged. When they feel like their concerns have been dismissed, they're more likely to call back. Customers may complain about warm rooms, a muggy home, more dust than usual, and long runtimes. It's our job to listen to the complaints, make sure we understand the customers' concerns, and address their concerns by checking the thermostat, testing the equipment, and taking readings. While we could explain what's going on in detail, we don't want to talk the customers' ears off and act like we're dismissing the customer's concerns. Ultimately, the customers care about getting their house cooled down and feeling comfortable above anything else. So, we could show customers the delta T readings to show them that their system is indeed working. You can explain the procedure to show the customer what you're doing, and you make the customer feel heard while establishing trust. We can also stop callbacks by closing out jobs thoroughly. Making sure you take detailed notes is only part of the procedure; you can help many property managers by sending them pictures of the system. Other customers benefit from written or visual guides that help them understand what you've done to their equipment. Above all, we want to make sure our customers' needs are addressed and that they have the tools they need to keep their homes comfortable. It's best to close out jobs slowly and ask customers if we can do anything else to improve their experience. If customers still have comfort complaints, it's a good idea to go into the attic and look for obvious sources of their discomfort, including kinked, poorly sealed, disconnected, or poorly strapped ducts. We sometimes avoid having conversations about ducts, but we can quote minor problems and readdress them in the cooler season. If the customer allows us to push back minor procedures, that may also prevent callbacks, as the customers expect to have imperfect conditions for a while. Above all, we need to make sure we're checking the equipment thoroughly after an installation. In some cases, the equipment may only be running one stage of operation, or it may not be set up for multi-stage operation. We must confirm the settings for DIP switches, motors, and controllers, and we need to verify that they're operating properly. We also need to clean the drain well and commission the system by checking the airflow BEFORE the charge. Looking at airflow indicators (like static pressure), using the TrueFlow grid to measure system airflow (if you have it), and carrying out full visual inspections will help us ensure we have proper airflow. Visual inspections can help us find problems with the ductwork, jammed filters, and other potential causes of poor airflow. Beginners can get better at testing static pressure with experience and repetition. We also want to minimize turbulence and take other practical measures that improve airflow. Whenever we make changes to the ductwork, it's our policy to add balancing dampers to help control the airflow. However, we also need to check the static pressure across the balancing dampers each time we make adjustments. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan covers Low AC Refrigerant Charge, How to be SURE about it and Does it really need Freon?. He describes the role of superheat and subcooling to verify that a system is low on charge so that you don’t add refrigerant unnecessarily. Subcooling tells us how much liquid is stacking in the condenser, with higher numbers representing more liquid and lower numbers indicating less liquid. We need to feed the metering device with a full column of liquid, but we don’t want excessive subcooling; too much liquid in the condenser will raise the head pressure and the compression ratio. In refrigeration, there will be a sight glass to indicate that you have a full line of liquid going to the metering device, so connecting gauges to check the subcooling is less important. Superheat indicates how much liquid we’re feeding the evaporator coil. High superheat indicates a starved evaporator, whereas low superheat may bring liquid back to the compressor. The superheat should be high enough to ensure that we won’t deal with compressor flooding, but it shouldn’t be high enough to indicate a starved evaporator coil. A visual inspection is also critical; filter restrictions, dirty coils, and improper thermostat settings may cause your readings to be off. Once you’ve verified that there are no obvious airflow issues, you can check the superheat and subcooling to begin verifying the charge level. Subcooling will generally be the main indicator of the charge level for modern residential systems. After subcooling, suction pressure warrants the most attention. You can figure out the suction pressure by figuring out the evaporator TD. You can then use that temperature to refer to a P-T chart to get the corresponding suction pressure. If the TD is lower than the design temperature difference (DTD), the system will have a lower suction pressure than normal. If the suction pressure is low, double-check to make sure that the coil isn’t frozen and that there are no airflow restrictions. We can also look at the condensing temperature over ambient (CTOA), which is usually more variable than the suction pressure. The CTOA refers to the difference between the saturation temperature at the condenser and the ambient temperature. In cases with a 15-degree design CTOA, the condensing temperature would be 15 degrees higher than the ambient temperature (105 degrees on a 90-degree day). We can then use the condensing temperature with a P-T chart or app to figure out the head pressure. A low delta T may also be an indicator of low charge. The telltale signs are a low condensing temperature, low evaporator temperature, low subcooling, and high superheat. To get the most accurate readings, you should ensure that there are NO airflow restrictions and that the Schrader cores have been depressed if you take your readings with gauges. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

RACT manual co-author Eugene Silberstein joins Bryan to talk about the titular topic of his book, “Pressure Enthalpy Without Tears.” “Pressure Enthalpy Without Tears” is a book that introduces engineering concepts to HVAC technicians in a way they can understand and apply in the field. Enthalpy is a fancy way of saying “heat,” and we use it to refer to the total heat content (BTUs). The pressure-enthalpy chart shows the relationship between the refrigerant pressure and enthalpy in a system; it’s like a P-T chart that shows the relationship between heat content instead of temperature. Each refrigerant has its own pressure-enthalpy chart, but the points and lines on the chart usually form a right trapezoid. Dirty air filters and other less-than-ideal conditions can distort the trapezoid or shift it on the chart. Each side of the trapezoid represents the refrigerant inside a major component of the HVAC system: evaporator, compressor, condenser, and metering device. The pressure-enthalpy diagram allows you to get a look at individual components while keeping the entire system in mind. To plot points on a pressure-enthalpy chart, you need the high side pressure, low side pressure, condenser outlet temperature, evaporator outlet temperature, and compressor inlet temperature. Pressure is usually measured in absolute units (rather than gauge units), but ballpark estimates are typically sufficient. Entropy is another concept we need to consider. Compression theoretically leaves no additional entropy and is reversible. Crossing a line of entropy means that a process is no longer reversible. Eugene and Bryan also discuss: Technicians vs. engineers Temperature vs. heat content Psychrometric and pressure-enthalpy charts Using the pressure-enthalpy diagram to assess operation costs Electrical measurements Predicting compressor failure Putting passion into learning and trades education You can visit https://www.escogroup.org/ to purchase “Pressure Enthalpy Without Tears” and access all of ESCO Group’s resources. You can also use the code HVACSchool22 for a discount on ESCO Group’s eLearning services. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This 3D video shows how to do an air handler install for a heat pump system. It is a companion piece to our condenser 3D install video ( https://www.youtube.com/watch?v=dwrbJKlHw6o&t=1949s ) and is primarily based on best practices for our Central Florida market. Before you leave the shop, ensure that you have the proper equipment, tools, and supplies. The model number needs to match the one on the proposal, and you need to make sure that you have all of your duct fabrication materials. When you arrive at the job site, recover the refrigerant from the old system. Purge hoses and weigh out the charge. Close the refrigerant lines once you’ve finished. Ensure that you have proper eye protection and that you wear a respirator when working in contaminated areas or are cutting duct board. Lay down drop cloths and make sure you have a means of disposing of garbage responsibly. Before you remove the old equipment, the circuit breaker should be off, and you need to test each leg of power to ground. Clean and cut the copper tubing. Cut the drain with PVC cutters and disconnect all of your low-voltage control wires. Use a level and mark the duct board where it needs to be cut to get the squarest possible cut. Once everything has been cut and disconnected, you may remove the unit. Since the line set is open, now would be a good time to flush the copper tubing. We often replace the return box, and we replace wooden duct board supports with metal studs. To cut duct board properly, you need to account for the thickness of your duct and understand how the tools work. As such, be sure to measure the inside dimensions when planning and making your cuts. Once you’ve made your cuts, you can assemble the box. Once you’ve got the box assembled, tape it at the edge where it all comes together with silver tape. Use alcohol to clean the duct surface, if necessary, and use a tape squeegee to get the best possible connection. Then, go over the silver tape with fab tape and use an outward-cinching staple gun on the taped surface. With the duct assembled, you can make your endcaps with plenty of overlap. Once the duct and endcaps have been put together, you can apply mastic over the joints. Extend the new copper and PVC through the platform. Then, seal the chase. Once the PVC and copper are in place, you can assemble the plywood platform. The plywood should have openings for the unit and the copper and PVC. To assemble the platform, you would put the return box in its place and add the plywood faces around the platform, ensuring that the plywood is level. Fasten the plywood platform with basic screws. Using the large hole you just made in the plywood as a guide, cut an opening in the return box. Allow the unit to have a little bit of height over the return opening so that you can access the filter more easily. Apply mastic to the top, and then add the filter base and unit. Clean the existing supply duct with alcohol and a rag. Then, cut some more duct board and use it to connect the supply duct to the unit. There should be plenty of foil overlap, and we recommend going over that foil overlap with some outward-cinching staples. Apply silver tape, fab tape, and masking tape before applying mastic. Remove the tape before the mastic is allowed to dry. In some cases, the unit will be directly underneath the duct, but it’s more common for it to be offset. You will need to cut the duct board at an angle with precise measurements in the latter case. We also recommend sealing the base of the unit. Then, flow nitrogen while brazing in a new filter-drier and the air handler. Protect heat-sensitive components with a wet rag or a heat-blocking putty. Using a neutral or slightly carburizing flame, heat the base material to a cherry red color and draw the alloy into the joint. Do a pressure test and use a leak reactant to check for leaks. Pull a vacuum and ensure that the system passes the decay test. Ensure that you have the correct breaker size. Then, install the high-voltage wiring and auxiliary heat strips; the wires should be appropriately sized for the minimum circuit ampacity (MCA). Pipe in the PVC drain using a pipe sealant. Then, make sure your drain has a trap, vent, and cleanout. Assemble PVC connections with medium-duty PVC cement. Wire in the low-voltage connections at the unit. Set the ECM blower board to match the system tonnage as necessary. Make sure the connections are appropriate at the thermostat and seal the opening with putty. Test in heating and cooling mode, making sure to check your heat strip amperage. Then, you can set the charge after letting the system equalize by running for at least 20 minutes. Weigh in the charge with a scale. Check the system delivered capacity, delta T, total external static pressure, system airflow, and other important test measurements. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches a class about how to identify and rectify HVAC problems that stem from overcharge with refrigerant. When we charge systems, we typically add refrigerant via the suction line when the system is running. (You can only add refrigerant when the system is off if the system is under vacuum and has no refrigerant at all.) It's easy to overcharge systems with accumulators, as the accumulator may store liquid refrigerant before it gets to the compressor. People also may overcharge systems if they don't let the system equalize, if it's cold outside, or if the airflow is poor. You can't tell if a system is low on refrigerant from suction pressure alone, and some technicians may overcharge a system with refrigerant if they see low suction pressure. Technicians are also more likely to overcharge a system if they don't weigh in the charge with a scale and don't give a system time to equalize. Systems that have different stages of operation also need to be run at the highest stage during charging; failure to do so may lead you to overcharge a system. When you add refrigerant, it boils in the suction line and goes to the compressor, where it becomes pressurized. It becomes a subcooled liquid in the condenser and goes to the metering device. As the pressure drops in the metering device, some of the refrigerant will boil off. The metering device ensures that the evaporator is fed with refrigerant (and maintains superheat in the case of a TXV). When there is too much refrigerant in the system, some of that refrigerant will back up against the metering device and "stack" in the condenser. So, the head pressure increases, and the condenser becomes less efficient. As a result, the main symptoms of refrigerant overcharge are high head pressure and high subcooling. (However, a clogged condenser coil may also result in high head pressure and high subcooling. A visual inspection will often allow you to distinguish dirty condensers from overcharge; finding the differential between the liquid line temperature and the ambient temperature can help.) Low suction pressure is NOT a telltale indicator of low charge and likely indicates a restriction or poor airflow. So, we need to focus on multiple refrigerant readings and focus on the state of the airflow if we come across low suction pressure. Suction pressure is also not a good charging indicator. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Matteo Giovanetti from Micro-Air joins the HVAC School podcast to talk about the differences between soft starts vs. hard starts. Matteo explains how Micro-Air’s EasyStart works and how it differs from traditional hard start gear. Micro-Air’s “EasyStart” provides a soft start rather than a hard start. A hard start abruptly ramps up the voltage and current to the motor start; the EasyStart causes a much gentler start that results from a gradual voltage and current increase on the start AND run windings. The EasyStart marks a paradigm shift in how we think about “saving” compressors. It attempts to avoid drawing unnecessary inrush current, which is very common with hard starts. Hard starts may even lead to premature failure if the potential relay fails and can’t take the start capacitor out of the circuit. EasyStart has a different wiring configuration compared to hard start kits. A hard start kit consists of a start capacitor wired in series with a potential relay, which increases the torque on the compressor and removes the start capacitor from the circuit. The EasyStart has four wires; the black and white wires (L1 and L2) connect directly to the contactor, a brown wire that splices directly to the run winding, and an orange wire to the HERM terminal of the run capacitor. EasyStart also records information about the compressor during the first few startups to optimize its performance. It also monitors overcurrent and fault conditions with phase detection; when it detects a stall, it shuts off the compressor and doesn’t attempt to restart it until a few minutes have passed. Matteo and Bryan also discuss: EasyStart models Solar, generator, and RV use Impedance Positive temperature coefficient resistors (PTCRs) Compressors running backward EasyStart’s Bluetooth capabilities Tech support and product education Offering useful upgrades to customers Running and starting watt specifications for generators Learn more about EasyStart or purchase it directly from https://www.microair.net/. You can also contact the manufacturer by email at [email protected]. You can view the EasyStart home installation video at https://www.youtube.com/watch?v=bp4U-husy1o&ab_channel=MicroAir. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches a class about diagnosing poor compression, which is a less common fault than shorted and grounded compressors. In modern compressors, poor compression may happen due to stuck or active safeties. You’ll notice that the suction pressure may be high, and the head pressure will typically be low; there will be a smaller pressure differential between the suction and head pressure. However, those symptoms are also consistent with refrigerant bypass through a stuck refrigeration valve. The reversing valve relies on a solenoid to shift the pilot valve, but pressure differential primarily help shifts the valve. There are cases when poor compression makes the valve unable to shift fully. Good compression ratios for residential HVAC equipment are typically around 2.3-2.7. Higher compression ratios contribute to inefficiency due to a reduction in mass flow rate. However, a low compression ratio (below 2) indicates that the compressor isn’t pumping refrigerant. The compression ratio is the fraction of absolute discharge pressure over absolute suction pressure (at the compressor). MeasureQuick can calculate that ratio automatically. Compressors that don’t pump properly also often have low current, usually less than 50% of the rated load amps (RLA). However, a bypassing reversing valve may result in a normal or higher current. Potential causes of poor compression include broken valves or cylinder wear (on reciprocating compressors). In rotary or scroll compressors, you could be dealing with significant wear inside the compression chamber. However, the most common cause of poor compression is a tripped or stuck safety. You have to let a compressor power off and equalize the pressure to prevent poor compression caused by bypassing. Compressors might also run backward, meaning that it doesn’t pump properly. Overall, it’s best to shut the compressor off, let it sit, and make sure everything is connected before letting the compressor start up again. Before replacing the compressor, make sure you can rule out every other possible cause of poor compression. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan and Joel go out to an NBA Player’s home to solve a total duct DISASTER. They visit the home of Bo Outlaw and try to diagnose the root cause of an uncomfortable upstairs portion of the home and high power bills. Bryan starts off using the FLIR thermal imaging camera to check out the temperatures across the ceiling and look for potential insulation issues (conductive gains). When the A/C is off, the camera shows that the vents are significantly hotter than the surrounding areas. Some vents are hotter around the edges, and others are hotter in the center; a heated center indicates duct gains (radiant gains), and warm edges indicate infiltration (convective gains). The recessed lights also have some heat around the edges, though they’re not nearly as bad as the vents. When Bryan goes into the attic, he immediately notices that the ductwork is black. Black ductwork results in increased radiant gains, which would explain the hot vents. The duct is also unstrapped and sagging, and some of it goes into an open chase. There are also patches where the insulation is insufficient. Rather than having a plenum, there is just a piece of flex that leads into a duct triangle, which could result in undesirable static pressure and poor performance. Despite everything, the return box appears to be in good shape, and the evaporator coil is clean. However, the filter’s static pressure drop is higher than the equipment’s test static, which doesn’t even consider static pressure in the ductwork. With the gauges connected outdoors, Bryan and Joel check the refrigerant pressures, superheat, and subcooling. The suction pressure is very low, and the superheat and subcooling are also out of range. The delta T is 20 degrees, which indicates a likely airflow problem because the other readings aren’t within range. On the other unit, there is water in the return box, which likely indicates that the evaporator coil has frozen and melted. There is also what appears to be a supply plenum, but that’s really just a facade for some more flex duct. An ECM was able to compensate for the airflow restrictions, but it did so at the cost of a higher power bill. Bo’s main goal is for the upstairs to be comfortable without having to run the fans AND the A/C at the same time. The findings discovered by the Kalos team are high-value items for Bo and his comfort goals, so it’s important for technicians to investigate the entire HVAC system and bring any abnormalities or upgrades to the customer’s attention. That way, the customers can make informed decisions to meet their goals. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

John Ellis gives his HVACR Training Symposium presentation, "Selling IAQ Solutions" He explains how HVAC contractors can sell indoor air quality solutions ethically and make customers' homes as healthy as possible. We work in a process-driven industry; we have processes for installations, warranty claims, service calls, and so on. When we create an IAQ process that allows us to investigate the customer's home, analyze the customer's situation, and then quote the customer for a tailored solution, we can significantly improve a customer's quality of life, especially if they have debilitating conditions like COPD, severe asthma, etc. When it comes to IAQ products, our industry has a bad habit of just quoting the customer for a product instead of investigating and analyzing the customer's situation. To create that process, we need to start by collecting data during the investigation phase. We can source that data from customer questionnaires and several measurements. We also need to assess the effects of poor IAQ on the inhabitants, keeping in mind that these effects are often delayed and cumulative. When we take measurements, we need to remember that concentrations of pollutants and particulates can change over time. Once we've gathered that data, we need to analyze it. We compare the measurements to the information and feedback that the customer gave us. At this time, we also need to determine if the pollutant can be removed from the space; some pollutants are behavioral, and others can't be controlled as easily. Pollutants may also originate in the space or infiltrate the space from beyond the building envelope. We need to consider either removing the pollutants or diluting them. After we've analyzed the data, we can finally tailor a solution to the customer and give them a quote with several options and explanations as to how they work. The scope of work may include ventilation, filtration, air sealing, or a combination of those. When we approach customers as HVAC professionals, we have to keep in mind that medical conditions are often involved in conversations about IAQ, and emotions can run high as a result (especially when young children and their health conditions are involved). It's unethical to prey on those emotions, but we can be more effective if we understand just how invested customers are in their children's health. In some cases, we can improve the customers' quality of life significantly and reduce their reliance on pharmaceuticals to control respiratory conditions aggravated by their indoor environment. Overall, we need to recognize that mere IAQ add-ons and cookie-cutter IAQ solutions just don't work. We need to have a diagnostic process that allows us to create a tailored solution. Otherwise, we're no better than doctors who commit malpractice. Individual contractors who focus on delivering those solutions can also stand out by using their profitability to do good things for their community and provide better service. A lot of care needs to go into an ethical IAQ sale; IAQ jobs tend to take longer as a result. During installation, it's best to use the safest possible cleaning products, keep the area clean, make sure ducts don't leak, and make sure that no loose insulation or fiberglass can get into the airstream. It's also our job to educate the customer (and listen to the customer when they want to educate us about their conditions). Because ethical IAQ sales are so involved, the pricing needs to be fair for the work done; low bids only create a race to the bottom. When it comes to pricing, we need to be able to pay for the quality tools we use. John Ellis's pricing process is built into The New Flat Rate, and it has an IAQ module that allows you to generate appropriate prices for tiered solutions. The New Flat Rate starts the pricing process during the discovery/investigation phase and treats the whole house as a system. The software also has a training portal that can help you give customers a safe, healthy, and efficient home at a fair price. You can learn more about The New Flat Rate's IAQ pricing system at https://thenewflatrate.com/iaq Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Some admins from the HVAC School Facebook group join the podcast to discuss the art of moderating a successful community. Bryan is joined by Eric Kaiser, Ty Branaman, Michael Housh, and Neil Comparetto. A community based on a skilled trade gives people an inviting space to share information and ask questions. It’s also a space that allows people to practice how they present information. Groups also connect people across geographical locations, and we can get regional perspectives that change the way we think about things. However, community standards are necessary to keep groups professional and on-topic. Swearing is a slippery slope that may lead to personal attacks, which make the community hostile and unhelpful. The main goal is to keep a respectful atmosphere, and moderators have to draw the line somewhere, but there’s a difference between cultivating a productive atmosphere and being dogmatic. People who interact in those communities need to do it for altruistic reasons, not to satisfy their egos. Giving detailed, accurate answers (ideally with a source to back up the information) is the best way to contribute meaningfully. Engaging in rigorous debates with an open mind is also a great way to see many different viewpoints. Debates in HVAC communities are great, but they require boundaries and mutual respect between debaters. Namecalling, blaming others, or dragging politics into the discussion is unproductive. Overall, it’s best to stay positive and try to keep things helpful, and admins try to maintain an atmosphere that can be both serious and lighthearted but is always helpful and respectful. HVAC communities and groups are not places to share other groups, content, or job postings. These groups are not marketing centers; they are forums for learning and discussing the work we do every day. Ty, Neil, Michael, Eric, and Bryan also talk about: How they got started in online HVAC communities Unproductive arguments about codes Banning and muting members Receiving feedback Avoiding logical fallacies in debates How egos hold people back Trite and unproductive catchphrases, slogans, and jokes Responding to disagreements productively Communicating with people appropriately Admitting fault and refraining from judging others who are incorrect Moderating posts for quality and shareability Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This video is of Rick Streacker’s HVACR Training Symposium presentation: “The Impact of Static Pressure on Fan and Blower Motors” Static pressure acts on both sides of a blower, so it plays a major role in the operation of fan and blower motors. Fans and blowers help HVAC/R systems move air over the coils, which assists with heat transfer. We use fans on the condenser side in refrigeration and HVAC applications, but we also use fans on the evaporator side in refrigeration whereas we use blowers in HVAC. Blowers allow the air to move a greater distance (i.e., through ductwork) than a fan. Common fans include axial fans, which have propeller blades that rotate on an axis (and are affected by static pressure). Free air with minimal static pressure on the fan blade results in a low load on the motor. However, adding more static pressure increases the load on a motor, which would reduce the speed of a PSC motor and increase the amperage. Static pressure, amps, and the load on the motor are all linked. Motor speed and temperature are also affected by those three factors. A residential condensing fan might only have a static pressure of about 0.3”w.c, and higher static pressure is often associated with a dirty coil and a higher amp draw on the motor. A motor with a higher load due to increased static pressure will likely run slower and hotter. Centrifugal fans are also known as forward-curve blowers. Unlike the axial fan, a centrifugal fan brings air through the inlet, changes its direction by ~90 degrees, pressurizes it, and discharges it. When there is no static on the blower, it will operate at a higher amperage, more slowly, and hotter. Centrifugal fans need higher static pressure to work optimally. We can think of the load on the motor as “boxes of air” (CFM), and that value will be influenced by horsepower, restrictions, and system design. Centrifugal fans that have to work harder to move more boxes of air will run higher loads, which may lead to overload conditions. The filter or furnace door will provide a restriction and increase the static pressure, decreasing the load on the motor, making the amps drop, and helping the motor run more quickly. In most cases, the HVAC/R system design is tailored to a specific load and has a relatively small operating window, and the fans and blowers need to operate within that envelope. That’s why we like low amps, but amperages that are too low to move air effectively are undesirable. If the load is above or below what the motor has been designed for, the motor’s performance and longevity will drop. Even if a restriction keeps the fan or blower motor in its intended operating envelope, a dirty filter or coil could also affect the capacitor’s longevity. Sometimes, technicians replace blower wheels but keep the housing. A mismatch can cause the performance to drop, so we want the replacement blowers to match the characteristics of the first blower wheel. To pick a good replacement, we need to be able to tell the wholesaler what our target CFM and static pressure are. In many cases, we’re dealing with air-over motors, which means that the air itself is what keeps the motor from overheating (compared to belt-drive motors, which are self-cooling). The right load needs to be on the motor; otherwise, the motor will overheat. So, the replacement motor should be equal to the amps of the original motor but not more than 25% stronger. Upon replacement, we need to check the motor amps with all of the components in place. ECMs (electrically commutated motors) are sometimes variable-speed motors, but they are all air-over motors and rely on the proper load for cooling. However, ECMs tend to be easier to design for the appropriate static pressure. So, we can factor loads into the design more easily, whether the ECMs are used in fans or blowers. In fans, ECMs tend to be constant-speed motors, but their designs can be refined for blowers and tend to be more variable than PSC motors, but they can’t overcome very bad static conditions. Fans and blowers react to static pressure the same way, but the motors themselves react differently. Although we can’t correct bad static conditions with ECMs, we can modify the ductwork to correct the bad static conditions. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan explains why barometers are a SCAM and why barometric pressure isn’t helpful in the HVAC industry. We can look at two areas of vastly different altitudes (Death Valley, CA, and Denver, CO) and notice that the barometric pressure is pretty close to the same. That seems odd because the latter should have far less pressure than the former because there isn’t as much air pushing down on an area well above sea level. Below sea level, there is a lot more air exerting pressure on everything below. The truth is that regional barometric pressures are normalized to sea level. So, the normalization makes the reported barometric pressure of Death Valley and Denver similar (even though the actual pressures are very different). In reality, the barometric pressure of Denver is around 24.7”Hg, which translates to around 12.1 PSIA (compared to the 14.7 PSIA or 29.92”Hg at sea level). Thus, using barometric pressure to calibrate tools is difficult and unreliable, and you must either do the math or consult a chart to convert normalized pressure readings into accurate ones. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches a class about accumulator facts and tips. He explains what they accumulate inside an HVAC system, covers some common problems, and gives some tips on how to use them. Accumulators are designed to accumulate liquid refrigerant before that liquid can reach the compressor. Liquid should never get inside the compressor. When liquid floods the compressor, it washes out the oil. Many compressors are also refrigerant-cooled, and that refrigerant has to be a cool vapor, not a liquid. Accumulators are more common in Carrier heat pumps because those systems have fixed-orifice pistons that don't control the superheat. Therefore, the accumulator is an additional safety measure when there is no control over the superheat in a wide operating envelope; it interrupts the liquid before it can affect the compressor. Although the accumulator can become liquid-locked and feed back, it's unlikely. Accumulators also prevent slugging. However, modern compressors are unlikely to slug due to their refrigerant-cooled nature. Slugging happens when liquid gets into the compression chamber. Overall, getting liquid into the compressor in any capacity is undesirable because it starts foaming the oil and ejecting it from the compressor. The oil lubricates the compressor bearings, which keeps the compressor working for its entire lifespan; premature failure may happen if there is too much mechanical wear without the oil. When oil is ejected from the compressor, it also goes to the rest of the system and can get stuck in the evaporator coil when it gets more viscous. The accumulator has a U-shaped tube with a small pickup hole at the bottom, which picks up oil. (Oil is heavier than liquid refrigerant and will sink to the bottom of an accumulator.) If that bottom port gets blocked, oil won't be able to get through and will get stuck in the accumulator, so it can't lubricate the compressor. Copper shavings, dirt, and carbon flakes may block that port. There is also a port near the top that stops the accumulator from becoming liquid-locked. In some cases, oil also may not return to the compressor due to long line sets. Long lines require the HVAC/R technician to add more refrigerant, and special considerations need to be taken to make sure that liquid refrigerant doesn't migrate (or vapor refrigerant doesn't condense to a liquid in the compressor). These strategies include liquid line solenoid valves, hard shutoff TXVs, and crankcase heaters. When we replace a compressor, we want to pay attention to the accumulator. Replacing the accumulator is perhaps the best practice, especially in a burnout situation, but the old accumulator can be reused if it's flushed and completely cleaned out. It's a good idea to dump out the accumulator and analyze the oil; a lot of contaminated oil indicates a lot of oil loss and could be a burnout. The accumulator is a good place to test the oil, too. Charging a system with an accumulator is different from charging a system without an accumulator. Liquid charging could result in refrigerant going into the accumulator and getting cold, which makes it hold liquid refrigerant and indicate undercharge because the subcooling won't go up (even though the system could be overcharged). So, using a charging scale and giving the system plenty of time to equalize will help prevent that from happening. With labor, refrigerant, and callbacks being as expensive as they are, the small details matter. It's also worth noting that motors and electrical parts often fail due to mechanical conditions, not electrical ones. So, burnout isn't always caused by lightning strikes, start capacitors that aren't taken out of the circuit, or over-voltage conditions. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This video is the laid-back Ask Us Anything Q&A session from the HVACR Training Symposium. The panel consists of Bryan, Joe Shearer, and Eric Mele. Eric does a lot of commercial HVAC/R work for Kalos Services, and Joe is an HVAC/R contractor in the Tallahassee area. We had some questions about cleaning line sets. Joe started cleaning line sets with foam pigs instead of just using nitrogen, which can be unreliable. The other widespread option is replacing the copper entirely, which can be a time-consuming task. Foam pigs usually come out in one piece and don't often get stuck, but some of them can have pieces fall off if they run through poorly deburred copper. However, you shouldn't have any problems with foam pieces being left behind in the lines if you purge the lines with nitrogen after cleaning. You can also blow nitrogen through the other side if a pig gets stuck. It's usually best to move the pigs and flush from inside to outside, as the flush may have a chemical odor. We also had a question about the wear and tear on heat pump inverter compressors that run higher RPM in heat mode in colder climates. Compressors that run at a higher speed and with a higher compression ratio in heat mode will generally experience more wear than those that run at lower speeds with a lower compression ratio. Vapor injection can help keep the compressor a bit cooler, but the compressor will still be in rougher shape than one that doesn't work as hard and run as hot. Another question dealt with CO2 systems in Florida. Non-cascading CO2 systems are generally not ideal in Florida due to the hot climate. We also can't use adiabatic cooling to keep the CO2 below the critical point because we are in a high-humidity market. However, Eric has been working on a non-cascading CO2 system in Jacksonville, FL, and it will be more likely to work because it will have a cooling tower and water-cooled condensers. We received questions about whether the TXV sensing bulb location matters. Nowadays, we have modern TXVs that aren't as heavily impacted by sensing bulb location and orientation. The bulb's job is to exert pressure, and it merely needs to be able to pick up the suction line temperature; the contact area is more important than the location. (We also talk about insulating the sensing bulb and have a debate about what's really in a sensing bulb.) Bert asked about liquid line restrictions, which led to a discussion about hard shutoff (non-bleed) TXVs and how they work. You can identify liquid line restrictions by checking for temperature drops, but you have to be mindful of radiant heat, overcharge, and tool calibration. Bert also asked about Lennox's low compressor fail rates, which could be due to safeties and the use of TXVs instead of pistons. We also discussed the potential causes of damaged ECMs, including condensate problems, moisture migration, and evaporator coil freezing. We answered a question about leak rates with the system on or off; refrigerant will leak out of the high side faster when the system is on, and refrigerant will leak out of the low side faster when the system is off. However, pump-down solenoids and other accessories can affect that rule. Another question dealt with refrigerant oil breaking down when a vacuum is too low. Oil won't fractionate under very low vacuums. One of the online questions was about how young techs should go about implementing best practices in the face of pushback. A respectful approach generally works best, but we also have to accept that not everybody will want to change. Someone asked about choosing brands and whether it's okay to vent bath fans into the attic through the ceiling. Nowadays, there's little difference in quality from brand to brand, so value will be one of the main things to consider. However, venting bath fans through the ceiling and into the attic is NOT a best practice. We also discussed surge protection. Surge protection varies a bit by market, and it depends on the practices of the power company; buck-boost transformers will likely be more effective at managing incoming overvoltage from the power company over the long term. We received a question about residential monitoring systems and compatible business models. Those technologies can be valuable, but we also need to be realistic about a given company's commitment to maintaining those tools. Another question dealt with hard starts. Not all systems require hard starts, but hard start kits are often used on compressors that are old and don't require them. However, some manufacturers will require start kits if the compressor requires a temporary increase in current on the start winding (NOT the run winding). Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan gives the Kalos techs a lesson about nitrogen to share some Facts and Tips. He also explains how it can be detrimental to HVAC systems AND how we can use it as a tool in the HVAC trade. Nitrogen makes up about 78% of the air we breathe, but we want to keep it out of HVAC refrigerant lines because it is a non-condensable gas. It doesn't condense inside the HVAC system under normal conditions, so it takes up space, doesn't move through the system very well, and increases the head pressure. Nitrogen in the system also affects the pressure-temperature relationship. However, nitrogen is also an inert gas, meaning that it doesn't react with other substances readily. As a result, it's a great medium for pressure testing and to displace oxygen while brazing. Nitrogen also displaces water, which is highly reactive and can cause corrosion if left in the system. Nowadays, we also use highly hygroscopic POE and PVE oils, meaning that water is attracted to them; if POE oil comes into contact with water, hydrolysis occurs and produces acid. In retrofit situations, we can actually reuse the line sets of systems that previously had mineral oil, as mineral oil and POE don't create a toxic mixture or anything. However, mineral oil systems fared a lot better with moisture, so we need to make sure that we remove oil and moisture from the line sets if we decide to reuse them. When we flush the lines, we typically use foam pigs and send them through the lines with nitrogen. To prevent corrosion, we also purge nitrogen to displace any air or moisture in the lines, flow nitrogen while brazing to keep reactive fluids out of the lines, and pull a deep vacuum on the system. In our Central Florida market, we notice that corrosion is most common in places that run copper underground and irrigate with reclaimed water (which is high in chlorine and other reactive chemicals) or buildings with water softeners near the chase. We also use nitrogen for the pressure test. When doing a pressure test, you can pressurize the system to the highest safe pressure. You put nitrogen in on the high side and watch the pressure on both the high and low sides rise. If the pressure on the low side stops rising, then you likely have a hard shutoff TXV. To do leak detection during a pressure test, the pressures need to be equalized. For best results, we also recommend using a bubble solution on joints, valves, and other common leak points so that you don't have to rely on the pressure test alone to find leaks. When brazing, we need to know the difference between purging (or sweeping) and flowing nitrogen. Purging the lines requires you to send nitrogen through at a relatively high velocity to displace everything that's already in the lines, including oxygen. In the case of existing line sets, the goal of purging is to create turbulence that releases refrigerant and moisture from the system. Flowing nitrogen occurs AFTER you get all the air out, and it happens at a much lower velocity, only 2-5 standard cubic feet per hour. A deep vacuum is what ensures that a system is clean, tight, and dry at the end of an installation, after nitrogen has been purged, flowed, and used for a pressure test. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches the techs about ghost voltage. He explains what it is and why it happens. “Ghost” voltage refers to a voltage that we can detect but that doesn’t appear to be doing anything. It could also exist but go away once the circuit is energized. It can be useful to think about there being static pressure against water pipes and then having it go away when a faucet starts running. The meter itself is a load, as it creates an electrical path. A meter has very high resistance, and you’ll see voltages across the meter due to that high resistance of the meter. When there is an actual current and a lower-resistance load in the circuit, the “ghost” voltage disappears. When you energize the primary on the transformer and have an open circuit on the secondary, that transformer does not appear to draw any current even though we have 240v of electrical potential. Instead, there’s an excitation current, which is a very small current due to inductive reactance and back EMF. We often imagine that electricity consists of electrons moving in one direction, but electrons are really a bunch of tiny energy units that move erratically. The sine wave generates the motion of electrons, and the sine wave represents an electromagnetic field that generates the circular motion of a motor. So, adjacent wires can be affected by the electromagnetic field if they’re within range; they pick up tiny amounts of voltage in a phenomenon called “induction,” which is what happens when power from the primary goes to the secondary without actually touching the secondary. The same principle applies to the interaction between two sides of a capacitor. So, whenever possible, we want to keep conductors as far apart as possible. We can also use meters that have a low-Z setting, which uses a lower resistance than a typical meter and doesn’t pick up those “ghost” voltage readings. We can also see ghost voltage when you measure across a load (like a contactor coil) when you have an open thermostat switch. You may end up with 24v across the load, but that could drop to 0v when the switch closes. That’s because there could be additional resistance in the circuit, and the voltage drop exists because the movement of electrons is dynamic rather than static. When that happens, you can look for poor connections or other causes of high resistance. Veritasium video: https://www.youtube.com/watch?v=bHIhgxav9LY Check out the article on ghost voltage at https://hvacrschool.com/beware-ghost-voltage/ Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan explains the difference between 3-wire and 4-wire condenser fan motor wiring configurations. The differences between 3-wire and 4-wire configurations are especially important when you're replacing an OEM condenser fan motor with an aftermarket condenser fan motor. The main difference between the two wiring configurations lies in the utilization of the brown-and-white wire. The 4-wire configuration uses the brown wire as the capacitor lead and the brown-and-white wire as the capacitor common. Those two wires are actually the same; the brown-and-white wire is an automatic jumper with the actual connection inside the motor. In many cases, you're also replacing the factory or OEM capacitor with a universal dual capacitor. In those cases, you can use the 3-wire configuration by cutting the brown-and-white wire back at the motor and putting a wire nut on it or running it into the cabinet and capping it there. The three-wire configuration requires you to run a jumper from the white wire to the other side of the capacitor. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bill Spohn and Joe Medosch teach a class called "Building Science 101 for HVAC Contractors" at the 2022 HVACR Training Symposium. They cover the basics of building science and building performance as it relates to HVAC performance and design. Some critical design points to consider for comfort, health, durability, and energy efficiency can be remembered by ABCDE: airflow, barriers, control, dampness, and exchange. Airflow refers to the slowing or stopping of airflow into or out of a building. Barriers prevent the flow of air, vapor, or heat. Control over our equipment requires us to make sure the equipment has accurate sensing capabilities. "Damp" refers to keeping a building dry. Exchange requires us to exchange stale, wet air for fresh air that dilutes pollutants. To ensure that the building and HVAC design touches on all five areas, we need to use data to back up our decisions and consider upgrades as permanent improvements. The building blocks of building science can be summed up with the acronym "HAM," which refers to heat, air, and moisture. We are trying to control all three of those to give customers the best in terms of health, comfort, durability, and energy efficiency. To control those, we need to look at the building enclosure (envelope), pressures, and what's contained within a building. Everything in a house is connected, and we can rely on measurement and detection to help us identify problem areas (such as poor drainage) that affect the whole building. Controlling the average home is a challenge due to all of the holes in the structure, including windows, doors, and openings for piping and wiring. The air that comes in sticks to everything inside, and low-quality air can significantly impact occupants' health and comfort if they spend 50-75% of their time inside their homes. Fresh air isn't always "fresh" either, especially if neighbors are burning leaves, if you live in a smoggy area, or if the pollen count is high. The bottom line is that air leakage is a contaminant pathway (ESPECIALLY in vented attics), and we need to control it. Mechanical ventilation (like range hoods, dryer vents, and bath fans) can actually exacerbate air leakage. Indoor air can be even worse. Carbon dioxide, skin cells, pet dander, and cooking and cleaning chemicals are also pretty bad for indoor air quality. Filtration can help a lot, though. Building science fundamentals overlap with physics fundamentals; for example, one of the core principles is that heat moves from an area of higher temperature to lower temperature. If air can get in during the winter, then heat can escape your house during the winter. Air pressure is also a major player, especially when you think about the stack effect, the neutral pressure plane, and wind. In theory, insulation isn't an air barrier, but it's a bit more complex in reality. Insulation may or may not act as an air barrier; it must be up against the air barrier for it to be effective against air leakage. For the insulation to be effective, air sealing must be done BEFORE adding insulation. Air leakage can also accompany vapor diffusion through permeable materials. Moisture can also find its way into a home, especially as it moves from an area with a higher concentration of moisture to one of lower moisture inside the home. Moisture that gets through to the roof deck can rot it out over several years. Duct leakage is another significant driver of infiltration, especially because it affects the pressures in the house. Supply leakage causes air to be drawn into the home through the gaps and cracks in a home. Return leakage causes conditioned air to escape the home through gaps and cracks in the home. We can get an idea of the air leakage in a building by doing a blower door test. A blower door test requires you to replace a door with a blower door, and it usually depressurizes the house; you can watch the pressure with a precision manometer, and the blower door test gives you the data to determine how many air changes happen in a building per hour at 50 Pascals (if you also know the building volume). Knowing the ACH50 allows you to categorize a house as a passive house (0.6 ACH50 or fewer). You can combine a blower door test with infrared imaging to locate major leakage points and seal them with guidance, but you have to be mindful of solar gains. Pressure pans also allow you to record pressure data. In any case, a properly sealed house is more comfortable, healthier, and more energy-efficient than a home with uncontrolled air leakage. An airtight house can benefit from well-thought balanced ventilation (NOT a mere bath fan). Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This video is a recording of Tony Gonzalez’s HVACR Training Symposium presentation: “HVACR System Troubleshooting: Better and Faster Than Ever.” Tony covers some wireless troubleshooting techniques (and Fieldpiece tools) and how they can transform your HVAC business. In almost all areas of HVACR, your jobs will fall into three categories: installation, maintenance, and repair. Regardless of which type of job you do, you need to ensure that the system is running at the top efficiency and that the electrical aspects, airflow, and refrigerant charge are all dialed in. Wireless tools have evolved to allow us to take multiple readings at the same time to assist with the three tasks listed previously. Taking multiple readings at once is advantageous for efficiency and allows us to see relationships between measurements. If we want to take high-quality measurements, we need to take a few steps. First, we need to set a goal and understand what we’re trying to measure. We also need to understand what a measurement tells us, where to take it, which tool we need to take it, and when we need to take it. Taking high-quality measurements is critical because those measurements complement our senses during troubleshooting; we use our hearing, sight, touch, and even scent to gather information, and the measurements put sensory anomalies into perspective and add data. Tools that help us troubleshoot faster and more accurately will yield positive results for any HVAC business (and generate more revenue). Tony’s troubleshooting process includes understanding the problem, identifying it, correcting it, and retesting the system operation. To understand the problem, we have to ask pointed questions, let the customer talk, and listen to the customer’s answers. Identifying a problem requires us to inspect the system and take measurements. Measurements allow us to quantify airflow, electrical, and charge-related performance. A wireless meter allows us to take electrical measurements, including voltage, amperage, and resistance. Meters have several safety features, including high-voltage noise alerts, magnets on the back (for hands-free usage), LED lighting, and non-contact voltage. These safety features come in handy when working on high-voltage components like variable frequency drives (VFDs); VFDs also have a lot of electrical “noise” that makes it difficult to get an accurate reading, and a high-quality meter can measure voltage without being affected by that noise. However, those technologies can provide significant energy savings to the customer; with the right tools to measure power (in kW), you can show the customer the difference in electrical consumption, which validates the work you’re doing and builds trust with the customer. Airflow is multifaceted, and Tony focuses on airflow going into and out of the air handler. Tests that can confirm proper airflow include a delta T (temperature split) measurement and a total external static pressure (TESP) test. For the delta T, you can use digital psychrometers in the supply and return; the Fieldpiece psychrometers are flexible and allow you to get deeper into the duct while holding themselves in place. To take static pressure, you need manometers to measure the force of air against the walls of the ductwork. Fieldpiece offers two single-port manometers that function as a dual-port manometer, allowing you to distinguish P1 from P2 very easily with the Job Link app; the orientation is still the same as other manometers and is labeled as such. To gather data about the refrigerant charge, we need to take temperature and pressure measurements; we need a way to determine the saturation temperatures, superheat, and subcooling. Gauging up can result in refrigerant losses, but wireless pressure probes and temperature clamps can give you an accurate measurement in a minimally invasive way. For the fastest and most accurate temperature measurements with clamps, you should position the clamps as close to the service valve as possible; Fieldpiece Rapid Rail sensor technology makes their clamps more accurate and less likely to be affected by wind, corrosion, or other things that may cause the surface temperature to differ from the refrigerant temperature, and they let you know when the sensor circuit is closed. Digital manifolds are also attractive options, as they can allow you to take measurements without worrying about losses, and they can even do the math for you. To learn more about Fieldpiece, visit https://www.fieldpiece.com/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This video is of Eric Kaiser’s HVACR Training Symposium presentation: “Is a House Really just a Big Duct System?” He talks about how the building envelope behaves like a duct and affects occupant comfort and HVAC system performance. A house can be defined as a single-unit residential building that can be of varying levels of complexity and is outfitted with plumbing, electrical, ventilation, heating, and A/C systems. Ducts can be defined as conduits or passages used in HVAC to deliver and remove air, including supply air, return air, and exhaust air. We can contrast ducts and houses by looking at who/what inhabits them, air velocity, heat transfer, fenestrations, control of air direction, and volume control. People live in houses but not ducts, and we want lower air velocities in the house than we do in the ductwork. A house is also a place where we have to worry about multiple factors for comfort control, including radiant heat, and it has fenestrations that also contribute to comfort whereas ducts do not. Ducts, however, can control the direction of air whereas houses cannot. Ducts have intentional volume control, meaning that we can use dampers to control the volume of air intentionally; volume control in houses is rarely intentional (for example, opening and closing doors without any intention to affect the airflow). However, ducts and houses also have a lot in common. They both have a relatively fluid operation, meaning that we can balance or control comfort factors. Houses and ducts also have the potential to affect airflow to the equipment. Both of them also need to be sealed tightly if we want to have control over the operation. When we look at houses, we have to understand that there is a pressure envelope separating them from the outdoors, and fenestrations penetrate that envelope without actually affecting the pressure. However, routing ductwork can introduce another penetration that CAN affect the pressure and expands the pressure envelope; kicking the fan on will create a pressure differential. Air takes the paths of least resistance out of AND into a space, and the pressure differential is only part of the equation. We can use manometers to measure pressure, and some of them have resolutions that can read Pascals, which are very small pressure units. In any case, the pressure outside the structure is our “zero” reference; everything we test inside the house will be in reference to that pressure. (WRT = with reference to.) When doors close in the house, those respective rooms can go under positive pressure WRT the rest of the house and get too hot during the heating season; while that happens, the house goes under negative pressure and draws more air in. The room that’s under pressure will have air escaping to the rest of the house AND the outside, which cuts off the low-resistance path to the return in that room; the room will have more “dwell time” in that room, which makes the room feel “over-conditioned” and affects comfort in the entire home. Register sizing and placement are also vital for indoor comfort, as you want the conditioned air to blow on surfaces and affect surface temperature. Mechanical ventilation results in depressurization, and it can come from bath fans, kitchen hoods, and clothes dryers. Non-direct vent appliances (furnaces, water heaters, etc.) can also contribute to depressurization via the stack effect and must be taken into account. We can counteract those with makeup air (which should seek to neutralize the most-used exhaust), which can be interlocked with the exhaust. In an ideal world, the makeup air and mechanical depressurization would be equal, but that’s often not realistic. Makeup air should be filtered, and humid climates with makeup air units can benefit from dedicated dehumidification. We can design makeup air to come in through soffits, and we have to be intentional about placement, as always. It’s best to make the filter as big as possible, too. We can also include dampers to balance the air; undersizing wouldn’t allow us to make situational adjustments. ERVs or HRVs can also ensure a balance between the exhaust and intake air, but dehumidification can be a challenge in high-humidity markets. These are NOT intended for makeup air and are for ventilation ONLY. When designing the ductwork in a house, Eric recommends avoiding pressurizing rooms. He also recommends central returns on rooms with low airflow per room and ducted returns on those with higher airflow per room. As always, ducted returns require the use of the proper friction rate. Calculating the pressure drop of the house-based return path and blowing air on surfaces (not people!) are more of his tips. On the house side, control radiant heat transfer (affected by room color) and temperature stratification. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Sam Myers (Retrotec) and Genry Garcia (Comfort Dynamics, Inc.) share their symposium presentation: “RTFM!... But Wait, This House Has No Manual.” Houses don’t come with manuals, so Genry and Sam explain how to manage comfort in a home without a manual. The house is a system, and occupants may have complaints related to IAQ and comfort. If those complaints can’t be addressed with the HVAC system, we may have to look at the building envelope, which serves as the container for conditioned air. Leakage and distribution of leakage can affect comfort, especially if discomfort is more severe in some rooms than others. The HVAC system or exhaust fans may also change the building or individual room pressures while running. Genry and Sam addressed those factors in an HVAC School article, which you can find at https://hvacrschool.com/what-if-houses-came-with-manuals/. Buildings have an outer skin that separates the inside from the outside, often called a building envelope or air barrier but sometimes known as a pressure boundary. Ventilated attics can be very leaky, especially where the drywall meets the top plate, and locations with penetrations or uncapped chases also often present problems. To test for envelope leakage, you must use a blower door; depressurization is done to exaggerate the leaks in a home. If we know the fan pressure and surface area of the hole, then we can calculate the flow. You can locate individual envelope leaks by PRESSURIZING the house and using a smoke machine to see if it gets swept up under the doorway. The smoke exposes leaks under exaggerated pressure conditions, so it effectively leads you to the leak. Equipment sizing is also important for comfort; an oversized system can lead to poor humidity control inside the home due to short runtimes. If the HVAC system doesn’t match the house, then the occupants may feel uncomfortable. Blower door tests can expose some issues with leakiness, but they don’t address mechanical-driven infiltration from the HVAC. Running HVAC units can drive air into or out of the building via leaky ducts and unbalanced rooms. Balance checks with a manometer can allow you to determine how rooms are pressurized in reference to the main body of the house. In general, individual rooms should not be more than 3 Pascals above or below the pressure of the main body of the house. However, rooms could still be balanced with inadequate supply air reaching the room, which can also cause comfort problems. Leaky supply ducts can cause too little conditioned air to reach the supply registers. Leaky return ducts can allow too much unconditioned air from the attic to enter the return, which can decrease the indoor air quality. Some rooms come under negative pressure compared to the rest of the house, indicating that some poorly sealed areas of the room may be responsible for leakage. A relatively inexpensive thermal camera can be used to locate these leaky areas. You can also check for gaps and cracks on the outside of a building to locate potential leaks in the building envelope. When checking pressure balances, you must still refer to the blower door test results to interpret the individual room pressures. The initial blower door test is a piece of the puzzle when we look at the envelope leakage for the whole building. Genry and Sam also use a simulator to check the pressure and find solutions for hypothetical cases. The hypothetical room is too positively pressured when the door is shut. In cases like that one where we need to get air back to the return, we may consider a dedicated return, transfer grille, or jumper duct as a solution. When the fan speed is the same as it was in the first case but in a leaky room (with a big, leaky chase), we could consider locating and sealing the leak. Leakage also depends on the size of the hole and the velocity of air flowing through the hole. Oversizing a system or changing a motor (such as going from a PSC motor to an ECM) can cause leakage to worsen. Visit Retrotec’s YouTube channel at https://www.youtube.com/user/RetrotecEnergy/videos. Learn more about Genry Garcia’s work and business at https://www.cdi-hvac.com/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan spends some time discussing duct types and tips at the Kalos morning meeting. He talks a bit about the differences between various types of flex ducts and talks about fabricating duct connections. Timestamps: 00:00 Intro 00:14 Black flex duct vs. silver flex 04:02 Duct sweating 06:53 Preventing duct sweating at connections 08:24 Duct liner best practices 09:14 Vapor barriers 10:30 Panduit straps vs. silver tape 11:51 Contact cement vs. silver tape 13:21 Outward-cinching stapler use 14:26 Overview of tips 15:09 Running flex ducts properly to prevent compression 16:35 Outro We occasionally come across black flex in Florida, which isn't the same as trailer flex. The black flex is water-resistant and tends to handle moisture a bit differently than a silver flex duct, but it is sometimes erroneously replaced with silver flex or used as trailer flex. The silver flex duct is reflective and tends to reflect heat from the roof decking, whereas the black flex absorbs that heat and results in greater thermal gains inside the duct. Although there is variation between manufacturers, silver flex tends to be a bit more durable than black flex. However, black flex is FAR less prone to sweating than silver flex. Flex ducts tend to sweat at connections, where the insulation has been compressed, and wherever it touches another surface (like a truss or another duct). Condensation occurs at those locations because they tend to be cooler than surrounding areas (and are more likely to reach the dew point). The ducts and air handlers can also sweat if they're not touching but merely shade one another. When you're making a connection, make sure you understand that condensation is most likely to occur at that point. Be sure to seal it completely and let the mastic (duct sealant) dry on the collar before applying the outer liner to it. Whenever you must use wet mastic, it's best to keep mastic tape on hand to use as a backup option. It's also worth remembering that a Panduit strap is just a mechanical connection and won't stop leakage. Compression can also cause duct sweating, so address points of potential leakage and make sure you're pulling the outer lining properly (without bunching the insulation). However, you need to roll the edge of the lining a bit to maintain a vapor barrier on the outside; that vapor barrier must be completely intact to prevent water vapor from making it into the ductwork. The vapor barrier should be against the duct board and not be pulled back or compressed in any way. (Panduit straps can contribute to compression. Silver tape is generally a better option, especially if you use denatured alcohol and apply it smoothly with a tape squeegee.) Spray glue and other contact adhesives/cement are good for short-term contact, but it dries out and becomes brittle over time. So, we prefer silver tape to contact cement, spray glue, and fab tape. Outward-cinching staplers can be used to attach staple flaps. Overall, when you fabricate connections, you have to pay attention to the duct type (and material), proper strapping, and how tightly the flex duct is pulled. Having tightly pulled flex duct reduces sweating and turbulence. Ideally, flex duct should only exist in straight runs; we can rely on metal fittings if we need to make an angle. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this presentation w/ Trevor Matthews at the 3rd Annual HVACR Training Symposium, he teaches us how to find out more about a compressor story. He also does a compressor teardown, talks about repeat failure prevention, and shares some resources for troubleshooting Whenever we approach a failed compressor, we need to examine it carefully to get an idea of its story. For example, the copper plating could be compromised, and that could indicate that we’re dealing with acid contamination. We get acid contamination when moisture gets into the system via a poor vacuum, broken heat exchanger, or poor installation. Electrical failures can also cause a burnout, which would result in acid. Overheating, low oil, slugging, floodback, and flooded starts are other problems that have quite a few potential causes. We need to know the compressor’s story to fix the issue completely. We need to look for other clues, including refrigerant leaks, oil viscosity or return issues, washed-out bearings, scoring, loose wires, refrigerant migration, and more that are pertinent to a compressor’s story. Sometimes, we can’t determine a story without breaking the compressor apart. We’re clearly not going to break down a compressor every time in the field, but we can take failed compressors back and examine them later to learn from them. Before and during a teardown, our senses are our best tools for figuring out a compressor’s story. If you remove the head in the field and need to replace it, be sure to have new gaskets on hand. The compression ratio is important to consider when looking at overheating scenarios. You can find the compression ratio by dividing the absolute discharge pressure (discharge pressure + 14.7 PSI) by the absolute suction pressure (suction pressure + 14.7 PSI). High compression ratios also point to inefficient performance, so we need to look for conditions that cause the suction pressure to be too low relative to the discharge pressure. Generally, the discharge temperature should also be below 225 degrees Fahrenheit when measured 6 inches from the compressor. A suction line that's too warm will also result in a higher discharge temperature, so suction lines need to be insulated to prevent heat transfer in the suction line. To prevent overheating, we need to maintain compression ratios per the manufacturer’s recommendation, use low-pressure controls within the compressor operating envelope, prevent suction pressure drop, and (sometimes) use additional cooling methods. Flooded starts and slugging can all occur as a result of refrigerant migration. We can use discharge check valves, pump down cycles, crankcase heaters, bump start cycles, or simply keep the compressor in a warmer location. Floodback occurs when the liquid comes back to the compressor during operation, often as the result of low airflow or metering device problems. Anything that prevents liquid refrigerant from boiling in the evaporator can cause floodback, and you will read little to no superheat Overcharging and setting the superheat properly are vital to floodback prevention. When preparing for a compressor teardown, you will want to make sure that there is no power going to the compressor. Then, you’ll want to check the compressor type to determine how you’ll measure resistance. After checking the resistance, it would be wise to check the terminal plate and look for issues there. When you take the head off of a semi-hermetic compressor, leave two bolts before knocking it out of place. Check the gasket (if it’s still intact) and try to wipe off mechanical wear (to rule out overheating). When dealing with a reciprocating compressor, we want to press the pistons and see how the rest of them react (to check for wrist pin wear, which the compressor in the video had). The teardown is also a great time to take off the compressor pump, check for bearing wear, and “shake hands” with the crankshaft. All of those procedures can let you know a lot more about the compressor’s story. Learn more about Refrigeration Mentor at https://refrigerationmentor.com/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this class, Bryan gives the Kalos techs a refresher and goes over the basics of static pressure. He also differentiates between utility manometers and precision manometers, covering their appropriate uses. Utility manometers are your typical standard service manometers; they are designed to measure pressure in inches of water column ("WC, "H2O, or inWC). Inches of water column are smaller units of measure than PSI, and they're ideal for static pressure and gas pressure. Some utility manometers have one port, and others are dual-port manometers. Single-port manometers require you to zero them with the hoses on before taking the measurement. (Accurate zeroing is very important, especially as pressure continuously changes with the weather.) Dual-port manometers are often used for measuring a pressure differential, and zeroing is typically less critical because there is already another baseline for comparing the pressure. There is no such thing as "zero pressure." The closest we can get to "zero" pressure is 14.7 PSI, atmospheric pressure, so zeroing out single-port manometers is critical. Precision manometers use Pascals instead of "WC, which is a much smaller scale. We use precision manometers to measure duct leakage or envelope leakage (such as through a blower door test). We can also use the tiny Pascal scale to measure pressure imbalances between rooms and mitigate pressurization/depressurization problems. Static pressure probes look an awful lot like pitot tubes, which have tubes within tubes. A pitot tube takes a measurement that's a combination of static pressure and directional force. Pitot tubes then subtract the static pressure to yield only the velocity pressure; these tools require precision manometers to do their jobs properly. Pitot tube usage is more common on the building science side of the industry than HVAC service. Static pressure probes each have a closed end at the tip and some side ports, and they only measure static pressure. The probes face the opposite direction of the airflow and measure the force exerted in all directions (against the walls of the duct). Static pressure can be either positive or negative in reference to the atmosphere, and we typically measure it by putting one tube in the return before the blower and the other above the blower in the supply plenum in a fan coil or handler on a heat pump or straight-cool A/C (or below the coil on a gas furnace). In gas furnaces, the coil provides a pressure drop and is separate from the actual unit. The rated static pressure can be found on the data tag; a static pressure that differs from the rating will affect the system's performance (though there is typically an operating envelope). If the static pressure is higher than the test static on the data plate, a variable-speed blower will have to ramp up to maintain the airflow, increasing operating costs and the amp draw while negatively impacting the motor's longevity. Filter changes can cause the static pressure to change over time. You can also measure pressure drops over the filter and evaporator coil to isolate problems with filters or coils. Static pressure is NOT airflow; it's a pressure measurement, but it can be an indicator of airflow. Before we can measure the static pressure accurately, we need to make sure the system is producing the proper airflow (high-stage, no dehumidification mode). Although checking static pressure isn't something we need to do on EVERY call, it's worth checking when there are airflow complaints. Total external static pressure, supply, and return static are all worth checking to see if there are restrictions across filters or coils or other possible airflow problems. Filters can cause many problems, and static pressure readings can help you pick up restrictions caused by filters. Larger filters (4") with greater surface areas tend to create far less of a pressure drop and last longer than shallower filters (1"), which can clog and restrict airflow quickly. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This introduction to VRF technology class from the HVACR Training Symposium was taught by John Chavez. John explains the basics of how VRF technology works and why people might want to use it in commercial structures. The adoption of VRF technology is regulated by ASHRAE. VRF heat pumps are capable of some extraordinary feats, including achieving 100% cooling capacity down to -10 degrees and 78% heating capacity down to -15 degrees. The software that controls the HVAC system is the heart of VRF technology; the software controls the refrigerant flow throughout the structure, which adjusts the HVAC system performance. VRF and VRV technology are the same thing; VRV is just a marketing term used by one company, and it means “variable refrigerant volume” instead of “variable refrigerant flow.” As with all heat pumps, VRF heat pumps have indoor and outdoor coils that can reverse their functions depending on the operating mode (heating or cooling) via a reversing valve. Modulation is also an important function in VRF technology, as they have stepper motors that control EEV, compressor (inverter-driven scroll), and fan operation. The variable-speed compressor satisfies a wide range of load requirements while saving energy. VRF systems also appear as ductless 1:1 systems, have multiple zones (up to 8:1), and come in single-phase and three-phase varieties. VRF technology architecture consists of a central controller that connects to an outdoor unit, which then connects to a remote controller and one or multiple indoor units. All units share the same system control and refrigerant charge, and they may contain heat recovery systems. A heat pump with heat recovery differs from a typical VRF heat pump in that it has an extra component: a heat recovery box. Systems with heat recovery may have two-pipe or three-pipe systems and can perform simultaneous heating and cooling. (The two-pipe configuration is standard for regular heat pumps.) Algorithms control VRF technology by assessing the conditions and telling the equipment to operate a certain way based on those conditions. Whereas many heat pumps have difficulty providing heating in cold temperatures, VRF heat pumps optimize several parts of their system to allow the system to heat efficiently and effectively. VRF technology allows you to mix and match indoor units, use a flexible piping design, and get 150% connected capacity (connecting 15 tons’ worth of indoor units to a 10-ton outdoor unit). However, you must know your building profile (diversity) before making use of connected capacity effectively. VRF designs tend to be flexible and can have their controls easily manipulated by DIP switches. The compactness and economic nature of VRF systems also make them attractive due to their small footprint, low energy consumption, quietness, and cost-effectiveness. The variable-speed compressor allows VRF systems to match part-load conditions and regulate the discharge temperature for maximum compressor longevity. Lower electrical loads allow compressor startup to be relatively soft, as there is no inrush current. A variable-speed compressor also tends to have a high power factor and low reactive power, making it energy-efficient and able to handle precise temperature control without high kWh usage. In many cases, warranty returns are also very low, meaning that VRF systems are also beneficial to contractors. These systems also tend to be less expensive to operate and maintain over time than conventional HVAC systems. VRF systems use a remote controller to manage the set point for the indoor unit. These controllers are more complex than thermostats, as they can also control vanes and other parts of system operation. The outdoor unit works as a function of the connected capacity, thermistor readings, compressor hertz, LEV position, and pressure and temperature targets. The voltage gets converted from AC to DC, smoothed, and then back to AC power between the control section, microcomputer, and compressor. The system can also manipulate the cycles per second (hertz or Hz) from the power supply to match the equipment. PID (proportional, integral, and derivative) controls continuously adjust the EEV, which allows the refrigerant flow to vary based on the changing conditions. VRF systems also use smart coil technology, which are sensors that determine target superheat and subcooling temperatures. Some VRF heat pumps also come in the water-source, ground-source (geothermal), and hybrid varieties. Indoor units can come in high-wall, ceiling-suspended, or floor-standing varieties. They also have varied ceiling cassettes with built-in drain pumps. You can download this presentation from John’s LinkedIn page at https://www.linkedin.com/in/johnkchavez/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Steve Rogers and Bill Graber with TEC teach a class about dealing with a problem home and present A ''Basket Case'' Case Study. They collaborated on this presentation at the 3rd Annual HVACR Training Symposium in Clermont, FL. You can learn more about the symposium at https://hvacrschool.com/symposium/. When we approach problems, we have to determine whether the HVAC equipment or the house is the source of those problems. Ideally, HVAC contractors would be able to act as a consultant that refers customers to people who can solve the problem. The case study in this video took place in Miami and dealt with a house that was too warm; it didn't maintain the set point and had a high indoor RH%. To begin diagnosing the problem, the technician had to have a productive conversation with the customer and understand what the diagnostic tasks really accomplish. In a case like this, a visual inspection would let us see if ducts were leaking, but there were no obvious duct leaks in this case. The design review would allow us to determine if the equipment sizing is correct via a load calculation. (In this case, the sizing was almost perfect.) System airflow and TESP measurements can let us know if the equipment is performing properly (it was normal). House pressurization gives us an idea of the HVAC system's impact on the house pressure; you use the HVAC equipment rather than a blower door to manipulate the pressure (the difference was 2 Pa, which indicated a supply duct leakage problem). Room pressurization tests weren't applicable, so the technician had to go straight to the envelope (blower door) test. He found out that the house was leaky but not unusually leaky for a house of its age in Miami. (Plus, the Manual J accounted for the leakage but NOT the house's depressurization by the system.) TEC's See Stack simulation tool relies on indoor temperature, outdoor temperature, home height, and known leakage to estimate how much air leaks in and out (in CFM) and the house pressure at the highest and lowest points of a home. It also accounts for CFM exhausted from the home due to the depressurization leakage unaccounted for by Manual J. In this case, instead of 102 CFM (predicted by Manual J), the ducts actually had 384 CFM of leakage. The house sucked in hot air when it was depressurized, meaning that there was a larger load than what the equipment was sized for; the house was losing capacity AND increasing the load (especially the latent load) all at once. Overall, the house was covering only about 41% of the latent load and 74% of the sensible load. Manual J didn't account for the extra load from depressurization, so the "perfect" sizing was actually very far off. Most of the loads tended to stay consistent, but the infiltration load was variable and had the potential to cause severe comfort problems inside the home. A larger system would NOT have done the trick because it wouldn't have done anything to correct the leakage (depressurization would get even worse, sucking more hot air in from outside). Putting in a 5-ton unit would have helped the clients' comfort only a little bit. Instead, the recommended solution was to seal or fix the ductwork. Learn more about The Energy Conservatory (TEC) at https://energyconservatory.com/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches the Kalos techs the art of running a dehumidifier and AC dehumidify modes using an EcoBee thermostat and a 90-340 relay. The 90-340 is versatile and quite user-friendly, making it a great option for this task. The 90-340 relay has two sets of dry contacts, which don't have a connection to a power source. Energized or "wet" contacts DO connect to an electrical source. The contactor coil is an electromagnet that energizes the relay and pulls in the contacts; when the contactor isn't energized, the path between 1 and 2 or 4 and 5 is normally closed. On the flip side, the path between 1 and 3 or 4 and 6 is normally open when the contactor coil isn't energized. For the contacts to work as they're intended, they need to be wired as a switch, not a load. When you have a load, you need a power supply and a common for work to be done. Switches only exist to make or break a circuit. When we use an EcoBee or smart thermostat (with humidity control) with a dehumidifier or an AC with dehumidification mode, we would connect ACC+ straight to DEHUM (DH). (ACC+ is an accessory terminal that we can program.) Dehumidification mode on AC systems lowers the fan speed. When we don't use humidity-controlling thermostats, we would use a jumper between DH and R at the terminal block to energize DH all the time (and NOT dehumidify). Using a 90-340, you could connect the thermostat (ACC+) to one side of the contactor coil and back to common on the other side of the coil to make the circuit, forcing the system OUT of dehumidification mode. Under these conditions, the contactor coil would be energized and take the system out of dehumidification mode. When we use an actual dehumidifier, we have to take a 24v signal from the dehumidifier transformer and energize the DH terminal to turn the dehumidifier on. Dehumidification mode for a dehumidifier is the opposite of dehumidification mode on an AC unit. On a dehumidifier, DH must be energized, whereas it must be NOT energized in the case of AC dehumidification mode. We need the relay because we need a set of dry contacts, and it allows us to work with a separate transformer: the dehumidifier transformer. When we wire a dehumidifier to the relay, we want to make sure we just have 24v out and back in. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

As Bert welcomed his sixth child to the family and took some time off work, he began reflecting on his training life and figuring out what he could do to be a better HVAC trainer. He talks about his progress as he learns, grows, and develops into a better trainer. Bert thought that the 3rd Annual HVACR Training Symposium was an inspiring experience, and he wanted to improve his training. He realized that his Monday morning training classes lacked passion, and he wanted to change up his approach to get his passion back. Along the way, Bert grew out his beard, became an HVAC tech therapist, and encouraged his trainees to talk about their feelings. When that wasn't enough, he let the employees shoot their trainer with a bow and arrow. He realized that he wasn't being taken seriously, so he preached the word of HVAC from the rooftops. So, Bert began focusing on accountability; he wanted to put a system in place that holds technicians accountable. To do that, he made a noted list of potential areas of growth for each technician; if a technician called him asking for help, he'd write it down and follow up with them to make sure they learn the material they asked about. When Bert's not passionate, he shows up and does the bare minimum, which is an attitude that spreads to his team. To nip that outlook in the bud, Bert made it a priority to show up for his technicians in times of need. He made sure he was there to celebrate milestones and transitions in his trainees' careers, such as when they got their own vans or started doing harder service calls or quoted repairs. He also focused on mastering the virtue of patience. Everyone has gaps in knowledge and experience, and as a trainer, Bert knew that it was his responsibility to encourage his trainees to give them the courage to keep learning. While on hiatus from working, Bert also developed a step-by-step process for training all of his technicians. Its contents are still a mystery, but Bert is the greatest trainer in the world, so we all know that it'll be good. A reminder of Bert's tips: 1. Walk quickly 2. Don't pull out your phone during training UNLESS your company requires it for the task 3. Put in your own effort as you're learning (don't rely on a trainer to set your pace) 4. Don't complain or gossip 5. Learn how to count Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches how to stop Sweaty Ducts, Vents and Systems. This class covers the myriad of moisture issues that come with the approaching wet and humid season. He talks about duct and air handler sweating, attics, and dew point. Sweating air handlers and ductwork is generally outside the conditioned space. (Conversely, sweating vents are in the conditioned space.) We can help control attic conditions by adding vents or insulating to control the temperature in the attic, but controlling moisture is our main concern. Getting to the dew point allows the attics to sweat, which gets moisture out of the air and onto surfaces. When the air runs over the cool duct surface, the moisture condenses and becomes liquid water. (It’s just like running air over a cold evaporator coil.) Insulating the attic is usually NOT the answer because it drops the temperature even more and makes the ducts sweat even more. (Sprayfoam is a type of insulation.) If we didn’t have to worry about costs, we could keep an air handler or ducts from sweating by applying a space heater to the surface 24/7. Radiant barriers unfortunately have a similar effect as insulation; they keep the attic cooler, but they also cause the surface temperature to drop and be more prone to condensation. The best option to control moisture in the attic is to seal it and dehumidify it. That option will cause your power bill to rise, but it will keep the attic drier. Sealing the attic, controlling the temperature, and controlling radiant gains inside the attic will have much more of an effect on duct sweating than changing the temperature of the air inside the ducts. However, the best options will be expensive. We shouldn’t be afraid to offer expensive options, as it isn’t our job to decide the customer’s budget for them. The most important thing we can do is explain the consequences of each option and make sure the customer makes an educated decision. Restaurants tend to have some of the worst rusting and dripping problems around their vents because it’s very difficult to control moisture inside the conditioned space. In the summer, low setpoints, moisture loads indoors (kitchens and baths), and increased moisture loads outdoors all increase the likelihood of vents sweating during the summer. To combat summer moisture loads, try to get the customer to reduce the outdoor moisture’s likelihood of getting into the home (by closing windows and doors), ventilating in the kitchen and bathroom, and running the HVAC system longer with a colder evaporator coil. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

This video is a 3D animation showing how to use the full line of Refrigeration Technologies Viper products to clean HVAC equipment safely and effectively. Before you start using any of the Viper cleaning products, shut the power off and confirm that it is off with a voltmeter. You'll also want to lay down drop cloths to protect the work area and avoid causing damage to the customer's property. Then, inspect the entire system's overall condition and cleanliness; look for oil spotting as well, which may indicate a leak. Cleanliness is a crucial part of optimal system operation, as soil buildup can cause poor airflow and a myriad of other problems. The Refrigeration Technologies Viper product line includes evaporator coil cleaner (a self-rinse solution for cleaning evaporator coils in place), condenser coil cleaner (for cleaning condenser coils and blower wheels that have been pulled), and a brightener for exceptionally heavy soil buildup on outdoor coils. Each main cleaning solution also comes in a highly concentrated venom pack. All liquid cleaners (except the EVAP+ gallon jug) have a dilution ratio that you must use to mix the cleaner with water before applying it to the HVAC equipment. The EVAP+ gallon jug can be applied directly into the pump sprayer. Most Refrigeration Technologies Viper products can be applied to the HVAC equipment in a traditional pump sprayer or with a foam gun that connects to a hose. When using a pump sprayer, you will need to dilute the cleaner with water. To dilute the cleaner, add both numbers of the dilution ratio and divide that sum into the volume (in ounces, up to the fill line). The quotient represents the amount of cleaner you will add to the pump sprayer, and you will fill the pump sprayer up to the fill line with water to get your proper mixture. If using the foam gun, you will turn the dial on the center to determine how heavy or light you want your cleaning will be. When cleaning the evaporator coil in place, try to expose as much of the coil as possible to get the most access. Remove solid debris from the surface of the coil using a soft-bristle brush before applying the chemical cleaner. It's also a good idea to clean out the drain line and leave a wet/dry vacuum connected while you clean the evaporator coil. Add EVAP+ to the pump sprayer directly or apply and dilute the evaporator Venom Pack. Spray the coil with the cleaner and let it sit for several minutes. In many cases, you don't need to rinse the Viper evaporator coil cleaners. On dirtier evaporator coils, you may consider using the Viper aerosol can. You would apply the aerosol foam from bottom to top in a zigzag pattern and let it dwell on the coil for several minutes. Then, you may rinse it off with water. Clean excess foam and soil with a wet/dry vacuum, rags, or a soft brush. After cleaning the evaporator coil, you may apply Viper Pan & Drain Treatment to the drain pan and bottom row of the evaporator coil to keep sludge from building up in the drain. You'll typically use the foam gun outdoors with the condenser/Heavy Duty or Brite cleaners. Add the Viper cleaner to the foam gun, set your dilution ratio on the dial, and apply foam liberally to the condenser or blower wheel. Allow the foam to dwell for 5-10 minutes and then rinse it off thoroughly. When cleaning heavily soiled condensers, remove the guard completely and start removing some of the surface soil with a soft brush. Before applying chemical cleaner, rinse the coil with water from inside to outside. When applying foam to the condenser, work from the inside out and build foam from the bottom up. Allow the foam to dwell for 5-10 minutes and then rinse it off. When you have finished, reassemble the equipment and test it safely. Be sure to let components dry before you test anything. Learn more about Refrigeration Technologies Viper product line at https://www.refrigtech.com/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Jim Bergmann gives his presentation on system Commissioning w/ MeasureQuick at the HVACR Training Symposium. He talks quite a bit about system commissioning in general, measureQuick’s features and interface, and measureQuick training opportunities. Commissioning is the process of testing a brand-new HVAC installation within a new or existing building to make sure it meets the designer or owner’s specifications. Recommissioning is the process of retesting a previously commissioned piece of equipment to make sure it’s still performing up to standard. Retro-commissioning is the process of testing a piece of old equipment that was upgraded or repaired. Most systems we work on have at least one fault, which is a challenge AND an opportunity for our industry to improve the lives of customers. The measureQuick field process requires us to start wide; we have to think about the operation of the entire system, not just the appliance. That is where the visual inspection comes in. MeasureQuick gives flags to indicate when there may be problems, but the technician needs to be able to see the potential causes of those problems. When it comes to controls, we need to look for poor installation (such as holes in the wall), temperature swings, abnormal runtimes, incorrect temperature and humidity readings, breaker and conductor problems, and bad connections. We also have to inspect the ductwork, which may contain compressed, poorly strapped, or poorly designed duct runs, especially in cases with poorly installed flex ducts. General duct failure can also happen due to excessive heat exposure and disconnected ducts. Air leakage at the top plate also happens, and a telltale time is discolored insulation. Ducts may also be undersized, especially at the return, and they may have restricted return chases. During system commissioning, the filter also requires special attention. Make sure the filter slot is sealed (and properly sized) to help the customer significantly! Restricted or restrictive filters can cause significant duct leakage. You will want to make sure that you secure filters in place and that they have enough surface area to do their job without creating too much pressure drop. Watch your condensate assembly; there should be no dirt in the trap (and avoid double-traps), and the pitch should be appropriate. Condensate issues may indicate filter issues. Once you have done a solid visual inspection, you may begin using measureQuick. That’s when you gather data and deploy probes while the system is stabilizing. Your outdoor probes would go on the suction line or service valve for the suction line temperature, the service valve for the liquid line temperature, about 6-10 inches from the compressor for the discharge line temperature, and out of direct sun for the outdoor air temperature. Inside the conditioned space, your supply probe would go 6 to 10 feet downstream (to give the air time to mix), and your return probe would go at the inlet or drop. (The duct probe placement is the same outside the conditioned space.) Testing in the correct spots is crucial, as you may miss possible problems by measuring in the wrong place and failing to pick up on abnormalities. When evaluating the ductwork, check for unsealed attic entrances and other possible causes of short cycling. When checking static pressure, we want to make sure we’re checking TOTAL external static pressure, which includes pressure drops over the filter and indoor coil. When measuring the TESP, we have a static pressure “budget” that we like to consult when checking the static pressure in multiple areas. All measurements have an acceptable range, which we need to be aware of when making measurements. Out-of-range measurements can indicate minor faults, which can be symptoms of major faults and poor performance. MeasureQuick has all of those targets built-in and is programmed to identify minor faults that aggregate into major faults. MeasureQuick can also do pass/fail tests for subsystems, including electrical and air filtration systems. Once we get the system operating how we want it, we take those measurements and make a report that we can refer back to in the future. We call that benchmarking. Benchmarking allows you to use non-invasive testing moving forward. The measureQuick reporting system has always allowed you to save data and use geolocation, but it has recently been upgraded to include a consumer-oriented version that assigns the system a “grade” based on performance. MeasureQuick’s services include giving an overview of the system status, vitals scoring, and diagnostics. The project’s information updates when you add new readings to the app, and you can then generate a report explaining measureQuick’s findings with access to support. Nowadays, Bluetooth tools also connect to measureQuick automatically. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches a class about what superheat signifies. Superheat is the difference between a vapor’s actual temperature and its suction saturation temperature; it lets us know how much an HVAC system feeds its evaporator coil with boiling refrigerant. Liquid refrigerant goes into the metering device, and there needs to be enough liquid going into the metering device to achieve the desired effects of air conditioning but not so much that it floods the evaporator coil. We want to know the evaporation temperature (the temperature at which the refrigerant boils), which we can determine with P-T charts or apps like the Danfoss Ref Tools app. A cold evaporator coil is desirable for moisture removal, but an evaporator coil that gets too cold may freeze. We also don’t want the coil to get too cold because it could negatively affect the compression ratio by dropping the suction pressure. A cooler, lower-pressure vapor is less dense than a warmer, higher-pressure vapor, and the compressor has to do more work to raise that vapor’s temperature and pressure with each stroke or oscillation. So, you’re moving less refrigerant. As long as a substance is still boiling as a liquid-vapor mixture, it will maintain a constant temperature as heat continues to be added to it; the temperature won’t rise or fall until boiling or condensation has been completed. Refrigerant with a 45-degree evaporation temperature will be 45 degrees as it boils, but it will go higher than 45 degrees once it has completely vaporized. That additional heat is called the superheat. According to those rules regarding latent heat, it would stand to reason that lower superheat makes for a more efficient evaporator coil; there would be more boiling refrigerant in there. However, low superheat would put a compressor at risk of flooding if the refrigerant were to condense in the suction line. TXVs also have a minimum stable superheat that must be met. So, the efficiency of a lower superheat comes at the expense of increased flooding risk (which can lead to costly failures). TXVs can set the superheat, and they must be charged by subcooling. However, older piston systems would require the superheat to be set, and you would need to do that with the indoor wet-bulb temperature, outdoor dry-bulb, and a superheat calculator as you charge a system. If the superheat is too low on a TXV system, that indicates that the TXV is overfeeding the evaporator coil. On the other hand, if the superheat is too high, the TXV is likely underfeeding the evaporator coil. To prevent a failed TXV misdiagnosis, you must check several other things than the superheat; look for temperature drops across the liquid line filter-drier, airflow problems, and improper subcooling. Even when charging a system by subcooling, it helps to be aware of those conditions, the evaporation temperature, and the superheat. On residential TXV systems, a typical rule of thumb is that the superheat should be 10 +/-5 degrees. The readings can deviate from the rule of thumb depending on things like long line sets and the location of your data point. In some cases, up to 20 degrees of superheat is acceptable in those exceptional cases where we can’t do anything about the system design, even though that may not necessarily be good for the system over the long term. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan with HVAC School goes over residential AC system installation in his presentation from the BTrained HVAC training event in Birmingham, AL. He also talks about ventilation, dehumidification, ductless units, sensible heat ratio, the decay test, and triple evacuation. We measure static pressure with manometers quite often, but they don't actually measure airflow. In general, many people think that lower static pressure indicates better airflow and is more desirable than high static pressure, but many problematic conditions can also result in low static pressure (such as a conductor going to Y1 instead of Y/Y2). We can get a more reliable indication of airflow from using a TrueFlow grid than static pressure. However, in any case, the relative indirectness ad unreliability of static pressure should encourage us to look at the whole system for possible problems. Installation requires a different skill set than troubleshooting and service; however, installation best practices can be useful for all sorts of technicians. The installation can be divided into a few main phases: pre-planning, planning, demo, install, and post-install. However, many people focus on the demo and installation without putting a lot of care into the pre-planning, planning, and post-install steps. The pre-planning involves Manual J, Manual S, etc., where we can use our tribal knowledge WITH those sorts of calculations and building standards (or special climate considerations, especially when you may need more dehumidification to meet those building standards in tightly built new constructions). If you enjoy being involved in the modeling and design process while using field principles, you might get a lot out of using Kwik Model 3D. We can also use the pre-planning phase to consider the design, especially focusing on the envelope. We have to evaluate tongue and groove joints, insulation in the unconditioned space, can lights, radiant barriers (which keep heat out of the attic by reflecting the sun's radiation), dryer vents, and mechanical ventilation in the design. If we have ventilating attics, the important thing to focus on is sealing the attic from the space. Pre-planning is also the time to make sure everyone working on the project is on the same page. When designing an HVAC system and preparing for installation, you need to have a few discussions with the customer first. It's prudent to have discussions about indoor air quality and when IAQ products may be appropriate for a building. (Some more controversial products include PCOs and UV lights, but there is a time and place for those, and it's worth talking to the customer about why those things may or may not be ideal for the installation.) Done correctly, ventilating dehumidification is a good technology that can benefit many homes, especially if we also rely on ECMs to control the ventilation. Ventilating dehumidifiers work best when they tie into the supply duct, NOT the return duct. (The relative humidity in the supply duct is high because the temperature is lower than the return; there is much less absolute moisture in the supply duct overall.) Dehumidified ventilation air going into the return derates the HVAC equipment's ability to remove moisture. Dehumidifiers add a bit of heat, which increases the load and causes the system to have longer runtimes, which is better for dehumidification. The houses that need the most consideration are those with bad envelopes (leaking to the attic or outdoors), poorly installed ductwork, and inhabitants that run their thermostats too low. Some duct upgrades are also worth discussing. You don't HAVE to replace all the ductwork, but if you can oversize the trunks or ductwork near the equipment (and still fit it), it will typically be a good idea. Larger filters (and filter cabinets) slow down the air velocity over the filter media, which increases the filter's ability to catch undesirable particulates; there is also a lower pressure drop across the filter. Upgrading the filtration can be beneficial to indoor air quality as well as system longevity, efficiency, and performance. You may also want to consider seeing if the equipment can be downsized and still allow for satisfactory cooling in the summer; downsizing equipment may lead to longer runtimes and may make undersized ductwork more appropriate. When we're planning ductwork, we also have to think of total effective length (with bends) and velocity in the throat. Turning vanes can help, but smooth transitions in the throat will be more beneficial. When fabricating metal ductwork, friction rate is typically less of a problem than leakiness. As always, flow nitrogen while brazing during installations. There are no excuses NOT to do it (unless you're using StayBrite 8 and can't guild up oxides). In any case, you MUST purge with nitrogen. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan with HVAC School goes over AC pressures, subcooling, and superheat in his troubleshooting mindset presentation from the BTrained HVAC training event in Birmingham, AL. Bryan also talks a bit about his educational photo-sharing app, MechPic. The suction pressure and suction saturation give us an idea of the refrigerant’s boiling temperature. Evaporation happens at the surface and not necessarily at the boiling temperature; on the other hand, boiling happens throughout the entire substance and occurs at the boiling temperature. So, the “evaporator” is really a heat absorber where boiling occurs. A rule of thumb for suction saturation is that it should be around 35 degrees below the indoor ambient temperature at 400 CFM per ton. That differential or temperature split, also known as the design temperature difference (DTD), is typically 30-35 degrees in high-humidity markets that use 350 CFM per ton like Florida and Alabama, where the conference took place. Lower suction pressures generally result in a higher DTD, and higher suction pressures usually result in a lower DTD. When we look at head pressure, we’re actually learning about the condensing temperature over ambient (CTOA). The CTOA is the temperature split between the outdoor ambient temperature and the condensing temperature. In general, CTOA tends to fluctuate a bit more than evaporator DTD, but a rule of thumb is that it should be about 15-20 degrees above the outdoor ambient temperature. SEER ratings may also affect CTOA. A ratio of head pressure to suction pressure is your compression ratio. Higher compression ratios tend to lead to reduced compressor performance (moving fewer BTUs). Even though we tend to see high head pressure as the main problem to avoid, we should be aware that low head pressure is possible. There needs to be an energy or pressure differential for matter to move from one place to another, and we’ll have trouble moving refrigerant if the head pressure is too low. The most important thing is to make sure that the system is working in accordance with its design. Superheat is the degrees a vapor is above its saturation temperature, and it really tells us the amount of liquid that’s stacked in the evaporator. However, the evaporator and compressor superheat could be quite different due to heat gains in the suction line. Generally, we want to see 10 degrees of evaporator superheat (+/-5 degrees) on many AC systems. The TXV is supposed to keep superheat constant; however, some possible system problems can affect superheat beyond the TXV’s control (such as significant liquid line restrictions, though there are exceptions to that example). On the other side, subcooling refers to the temperature of a liquid below its saturation temperature. In an HVAC system, subcooling indicates how much refrigerant we’ve “stacked” in the condenser; lower subcooling indicates that we have little liquid refrigerant stacked in the condenser, and higher subcooling indicates that we have a lot of liquid refrigerant stacked in the condenser. (There can, but not always, be temperature drops across liquid line restrictions.) Refrigeration systems with receivers don’t necessarily have to rely on subcooling values to indicate refrigerant storage (a rule of thumb for residential A/C systems is typically 10 degrees +/-3). When we measure subcooling, we really want to know if we’re feeding the metering device a full column of liquid. If we want to increase subcooling, we can do that by reducing the liquid temperature via mechanical subcooling or increasing the condensing temperature. (However, we don’t want too much subcooling.) When we use the manufacturer’s specs to set our superheat and subcooling, we might actually be reducing the equipment performance, so we have to know exactly what our goals are. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan Orr talks about how HVAC technicians can isolate problems to diagnose faulty systems. He particularly focuses on using isolation diagnosis on a grounded compressor and in the low-voltage circuit. This presentation was given at the HVAC Conference in Birmingham, AL, presented by BTrained, LLC. Isolation diagnosis requires us to make a hypothesis about the system and isolate our testing to the problematic part of the system. Instead of going in and testing every single wire, you have to develop a process of elimination to get to the bottom of the issue efficiently. At Kalos, when our techs find grounded compressors, we make our techs pull the wires off, isolate the wires, put the top back on, and see if everything else runs when power is applied once again. (We call that the "redneck compressor test," and it's an alternative to bringing out your ohmmeter.) If everything else runs, then we can be confident that the compressor is grounded and proceed with further diagnosis. However, if nothing else runs, then we will know that we have a problem elsewhere. In cases with grounded compressors, we would bring out the megohmmeter to check resistance at the compressor terminals after we confirm that the problem is indeed isolated to the compressor. The lacquer in compressor motors can wear down and cause issues with the motor windings. In cases with time-delay issues on the low-voltage circuit, we do isolation diagnosis by checking for shorts in the Y or G circuits. We can rule out the red circuit and reversing valve immediately when we experience time delay issues. Once you have all your tools and an idea as to how you'll tackle a problem, you can use isolation diagnosis to troubleshoot the system. In cases where we have voltage, we need to make sure that the voltage doesn't drop. We can use components to test the voltage drop; for example, we can see if 24v power will energize the contactor at various points (though things get tricky when the common gets involved). Isolation diagnosis can help you solve all sorts of weird problems that your meters alone can't help with. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan explains what wide-narrow-wide diagnosis is in the troubleshooting process. He also explains why it’s so effective in the HVAC trade as well as how you can use it to do thorough work and earn good money. This video was taken at an HVAC training event in Birmingham, AL. When a good diagnostician walks into a home, they look at the problem very broadly or start with a “wide” approach to diagnosis. They don’t limit their scope to a certain component or head to the call with a fixed pre-diagnosis. Good technicians listen to the customer, look for new thermostats, check the filter, and note every detail they can that could be relevant to the system performance. Once you’ve noted all of the noticeable broad items of interest with the whole system, you can shift your focus to finding the main thing that is keeping the HVAC system from working. Check your static pressure and other diagnostic readings on the airflow side. Weigh the charge as well to see if you might be dealing with a leaky or overcharged system. Even if you don’t find any airflow or charge problems, you can still check those things to rule out possible issues. Pay attention to line set lengths, missing accessories (e.g., crankcase heaters), and start gear (capacitors) as well. Check everything you can before you run test the compressor. Being thorough is the key, and most good companies should allow you to be as thorough as you need to get a proper diagnosis. (However, that requires a balance of thoughtfulness and efficiency, and you need to charge an appropriate amount of money for good work.) Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan goes over the HVAC troubleshooting mindset, including the 5 Pillars of diagnosis, at an HVAC training class in Birmingham, AL. He also covers a few mental shortcuts you can take that still allow you to troubleshoot accurately. Good troubleshooters and diagnosticians listen a lot more than they talk. Troubleshooting requires us to find the problem and solve it, but the best diagnosticians figure out WHY the problem exists in the first place and takes steps to rectify the problem's source. The 5 Pillars are five measurements that tell us a LOT about an HVAC system's performance. (Believe it or not, static pressure is not on there. We technically could add delivered capacity, too.) You CAN use non-invasive testing to check the 5 Pillars, and you can use it to set the charge. The point of the 5 Pillars is to avoid setting the charge by just ONE value; that's just not a reliable practice when you have load changes and variations in performance. We currently have newer, more accurate ways of finding airflow and delivered capacity. (Those methods surely beat using a lot of math and a thermocouple covered in a sock soaked with distilled water!) Nowadays, delivered capacity could potentially be more useful than one of the original 5 Pillars, delta T. The other 5 Pillars include suction pressure, head pressure, superheat, and subcooling. However, suction and head pressure could easily be replaced by saturation and condensing temperature. The most important thing is to make a quick "if-this-then-that" mindset for troubleshooting, and having a set of 5 Pillars is a way to use heuristics (mental shortcuts) to your advantage in the field. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bert explains some of his best leak search tips. We use his tips for leak detection at Kalos, and although leak detection can be intimidating for beginners, it absolutely MUST be done right. Before you start any type of leak detection, you must confirm that the system is low on refrigerant. When you confirm that a system has a low refrigerant charge, you then need to estimate how low the charge is so that you can get an idea of the leak's size. Then, you can find the leak. The visual inspection comes first. You will want to look at common problem areas often touched by humans, such as joints. In many cases, the refrigerant or oil will leave spots or a trail where it has leaked; shiny pipes may look dull or wet. Check for discoloration of oil on top of the water in the drain pan as well. Leaks may be larger and faster on the high side of the system, so try to pinpoint the exact area when you have leaks at the outdoor unit. You'll also want to check the capillary tubes, look for oil lines, and watch out for rust on the accumulator. After you find a spot visually, you can bring out your electronic leak detector (heated diode, infrared, or ultrasonic). Know your electronic leak detector's limitations; otherwise, you might unknowingly pick up false positives. Move the leak detector from top to bottom; if you start from the bottom and go up, you might get a false point because the refrigerant is heavier than air and sinks. Once you get a hit, do a bit more leak detection before going back and confirming that you still have the hit. Then, you can use a liquid leak reactant on the possible leak area; bubbles will constantly form over the leak. (However, it's harder to use bubbles to confirm leaks between fins; in those cases, make sure you confirm it with your detector by going back several times.) Evaluate the leak to see if you have a leaky joint, if you can potentially repair the leak, or if you can take another course of action. Sometimes, you may need to get access to the chase to assess the line set for leaks. Schrader leaks are possible, but they are often not the main culprit of major leaks, so keep going through the entire system after you find one leak (or get a hit on the Schrader ports). Confirm Schrader core leaks with bubbles, too. Leaky refrigerant caps hold oil, so check those if you get a hit on the refrigerant caps. After you find and evaluate the leak, gather all the information you need from the system and the customer to determine the next course of action. Check for warranty information and see if labor and parts are covered. If you do a replacement, you need to think about replacing the filter-drier and recovering the refrigerant from the system. If you still can't find the leak after following all of these steps, talk to the customer about your options, including quoting and performing a line isolation test. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Sam with Kalos Services and HVAC School does a field demo with the new Hilmor lineset cleaner. The Hilmor lineset cleaner requires you to use nitrogen to force foam pigs through refrigerant lines, cleaning up residual oil and refrigerant as the pigs work through the tubing. Included in the Hilmor lineset cleaner kit is a threaded fitting, which allows you to use a variety of foam pig sizes depending on the tubing diameter. The Hilmor lineset cleaner also comes with a catch net to collect the foam pigs at the end of the line. Before cleaning the line set, deburr the copper to give the foam pigs a smooth point of entry. The fittings slide right onto the line, and you can finger-tighten the hose clamp on there. He attaches the lineset cleaner gun by threading it on. Sam starts with the 3/4" pig, which he slides into the chamber of the gun. Then, he hooks nitrogen up from the tank and discharges the pig by pulling the trigger. The pig comes out at the other end and stays in the catch net. Sam repeats the process with the 3/8" pig through the liquid line, thus cleaning both lines. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches the Kalos techs all about capacitors, including how they look on diagrams, why they fail, and how to handle them on service calls. He also does some capacitor and hard start kit mythbusting. Even though we may imagine that current travels across the capacitor, the electrons DON'T travel through the capacitor. Capacitors don't "boost" voltage or current, either; the microfarad rating is actually more likely to reduce or restrict the amount of current that travels through the start winding. It may be helpful to view the capacitor as a balloon or membrane that stores and releases electricity. As the voltage changes via alternating current (60 times per second for 60 Hz, 50 times per second for 50 Hz), we measure its average via the root mean square (RMS). So, the capacitor charges (through the start winding) and discharges 60 times per second from the same way it came. Capacitors have attractive forces due to the high surface area between the two plates; there is a large sheet of plastic with metal rolled into the capacitor. You can also think of a capacitor as a third hand to help spin a motor; when we spin wheels with our hands, we apply directional force instead of horizontal force. The legs of power act kind of like sources of horizontal forces, and the capacitor acts like a hand to begin spinning the motor. Three-phase equipment and ECMs don't require a capacitor because there are already three "hands" spinning the motor without help. On single-phase equipment, the start winding always has current running through it, not just on startup, even though we need another "hand" to help start the motor. That's why we have run capacitors. If the run capacitor is too small, the compressor might not start and will get hotter because the run capacitor generates heat in the run winding (not the start winding). When the rotor stays locked for any reason, including an undersized capacitor, the amp draw stays high until the compressor goes out on thermal overload. If the run capacitor completely fails, nothing happens on the start winding; no current moves through it whatsoever. A failed start winding may happen if the capacitor is wired in incorrectly, if the capacitor is too large, or if the hard start kit presents problems. So, be sure to do a thorough visual inspection of the capacitor and any other accessories. We need to be careful when using hard start kits; they don't add a phase shift but give us more current to hit the start winding. However, the start winding isn't designed to handle full current all the time; the hard start kit needs to be able to shut off or take itself out of the circuit, usually via a potential relay. The best hard start kit is almost always the OEM hard start kit, but aftermarket kits are acceptable for temporary solutions or when the unit lacks a factory recommendation. It's also worth noting that capacitors can indeed weaken over time without failing completely. Incorrect capacitor sizing is common, especially after capacitor or compressor replacements. Sometimes, technicians accidentally install a new run capacitor of the wrong size. In other cases, a new compressor may require a different capacitor size than the previous one; we can't just assume that the new compressor will have the exact same requirements as the previous one. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches the Kalos apprentices about a few condensate considerations beyond cleaning drains. The goal of keeping these considerations in mind is to do quality jobs and not have to return to a job site. Water from the fan coil ends up draining outside; the condensate goes into the drain downhill and then spikes upward in a trap and then exits the drain. There may be a lot of standing water in the drains, especially when the system is off. The standing water provides a breeding ground for fungi, bacteria, and other undesirable living organisms, making backups even more possible. Some drains have traps at the unit with a cleanout before the trap and a vent after it; the vent is tall and stays uncapped. If we were to leave the cleanout open, however, air would get sucked into the drain. We can leave the vent open as long as the trap is deep enough to create a seal and allow the column of water to overcome the negative static pressure of the system. Trap size depends on the system, but we typically use P-traps that are a few inches in length. The trap tends to get the dirtiest, which is why the cleanout allows you to flush water into the trap or clean it out with a bottle brush. Systems with multiple traps are undesirable, but as long as all the traps are sufficient, a water column may be strong enough to travel all the way through. However, air bubbles can form in systems with multiple traps. We often see double traps due to misalignment with the chase pipe, but those are easily fixed by removing the tee and pulling the drain up a bit. Drains can get nasty buildup if they have a low pitch out of the drain pan. On a horizontal drain line, we try to aim for at least 1/4" of fall per foot of horizontal run. Strapping is also critical to avoid sagging; systems should be strapped at least every 4 feet or so. Sagging can cause double and triple traps over time, especially if the pipework was poorly done in the beginning. The Kalos techs are supposed to find and rectify the double traps wherever possible. If that's not possible, we may have to rely on chemicals to get the hard deposits out of the drain. The float switch typically goes somewhere near the platform top. In many cases where the float switch is above the platform top, it will only trip if the water level in the pan is also high enough to trip the switch. So, we try to avoid overflowing shallow pans by keeping the float switch below the drain pan's level. Sagging platforms can also cause the float switch to back up, though. At Kalos, we need to learn to quote new platforms instead of holding off on dealing with sagging platforms. Static pressure can also cause drain issues. High negative static pressure may cause air to be sucked in all over the place, meaning that you get turbulent flow inside our drains. Make sure everything is as sealed as possible to avoid drawing air into the drain where it shouldn't be coming in. In horizontal applications, poor airflow, platform level, and improper pan installation can cause condensate not to go where it's supposed to go. If the insulation gets saturated, we need to figure out why before we ultimately replace it; we have to check orientation and clean the drain BEFORE we replace the insulation. Whenever you have to tape the insulation (or anything else), clean the surface with rubbing alcohol and microfiber towels first to make sure the surface is clean and will keep the tape fastened as long as possible. Spray glue is a type of contact cement, so you have to spray both surfaces, wait for it to tack up, and then press the surfaces together to form a bond. Whenever you have a horizontal air handler, there also needs to be some overlap with the duct in every direction to keep the horizontal drain pan in place. When cleaning drains, we have to clean horizontal portions, drain lines, and the drain pan. We should be using brushes, Panduit straps, and everything else at our disposal to get the drains as clean as possible. We should also be looking down the tees to look for signs of drain line buildup and be willing to quote drain cleanings when necessary. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Sam Myers with Retrotec talks to Bryan about pressures in the home and why they matter for HVAC solutions at IBS 2022. Technicians focus a lot on ductwork and airflow, but many of them don’t focus on how the building envelope impacts HVAC performance. A lot of the HVAC equipment’s performance is affected by the push and pull of air caused by leaky areas in the building envelope. If you have a room with too much air and another room with too little, you will have unbalanced pressures. Unbalanced pressures may result in discomfort and latent load issues, especially when unconditioned air is pulled in through the attic. Sealing the envelope well and using dampers as necessary can minimize the comfort issues caused by pressure imbalances in the home. Instead of just using manometers for static and gas pressure, we can also use high-resolution manometers under doors to pick up pressure differences. However, the manometer MUST be high-res to pick up those subtle (but palpable) differences in pressure. A blower door is also a great tool, especially when you use it with a thermal imaging camera; the blower door amplifies the temperature effects that a thermal camera will detect, especially if you also have a good delta T. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan has a bit of an industry nerd out with Ross Trethewey from “This Old House” and TE2 Engineering at IBS 2022 (the International Builders’ Show). Ross’s education and career have focused on mechanical engineering, especially with sustainable solutions. In building science, the key mindset is to think of the building as a system. Using that school of thought, Ross has developed building science and HVAC solutions that also consider indoor air quality and ventilation, such as hybrid VRF systems. Many of Ross’s solutions take the best aspects of air-source and ground-source heat pumps and apply those to hydronics. Some exciting applications for those types of systems could include simultaneous heating and cooling as well as the integration of domestic hot water. Demand control ventilation has been used for a long time in the commercial world, but its possible use in residential applications is another exciting thing to consider. With proper control devices, DCV would give us the opportunity to control temperature, humidity, VOCs, carbon monoxide, carbon dioxide, and radon. In residential applications, DCV has to be a delicate balancing act, as bringing in too much outdoor air would require us to condition that air. High latent loads also present challenges to some of the ventilation solutions in development. Serviceability is another challenge to DCV usage in residential applications; whenever an innovative system is brought to the market, very few people will know how to fix and maintain those systems. One of the possible solutions is to create instruction manuals and give education similar to what already exists for package units. 3D models and animations also help make complicated systems easier to understand. Ross’s presence on “This Old House” marks the third generation of Tretheweys on the show. Ross is excited to talk about building science and HVAC innovations and concepts while on the show. Heat pumps are also getting better, especially due to inverter-driven compressors, enhanced vapor injection, advanced control systems, and ECMs. Heat pumps are safer than gas-fired equipment, and we have made them work well in subzero temperatures (because we’re nowhere near absolute zero). Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan teaches the Kalos technicians Overloads and Safety Switches, including float switches and thermal overloads, and why they Don't Just Fail. A float switch is wired into the thermostat wiring to kill power to the system if the drain system begins overflowing. The switch opens to create an incomplete circuit, similar to how an open drawbridge stops traffic. Float switches are normally closed, and they open when they are filled with enough water. When a float switch opens, the first thing you should do is check to see if there is water inside; you want to see WHY the switch is open, not just replace the switch. If there is NO water in the open float switch, then you’ll want to check for a path with an ohmmeter. If there is no path, then it’s a failed switch. However, if a switch is failed open, it’s likely that it has been opened and closed many times in the past. Thermal limits can sometimes be called overloads as well. Those safeties open when a component overheats, such as a surge protector. Modern surge protectors use normally closed thermal limits that open when the surge protector gets too hot. High-limit and rollout switches on furnaces as well as thermal overloads on compressors and heat strips are thermal limit switches. Fuses work similarly, but they break completely instead of merely opening like a switch. Again, make sure you figure out why thermal switches opened instead of just replacing them. In furnace systems, poor airflow can cause the high-limit switch to open. Dirty coils, filters, and blowers are potential causes of thermal switches opening. A compressor could go out on thermal overload due to a failed fan motor. However, sometimes, thermal switches reset themselves quickly due to electric overheating on the windings. If you replace the capacitor and correct the locked rotor condition, then you won’t have the thermal overload anymore. Compressors also get too hot when there’s insufficient or way too much refrigerant moving through the compressor. When the compression ratio is high, a compressor will run hotter than it should (especially due to low suction pressure and high heat pressure). Systems with long runtimes and excessive superheat can also cause compressors to overheat. All sorts of restrictions can also cause overheating. In those cases, the compressor should be cooled with water from a hose. To tell if a thermal switch has been reset, put your meter on the ohm scale with the ringer on and put the leads on your contactor across the two legs. Generally, the condenser fan motor will have high enough resistance to prevent your meter from ringing, but the compressor has low enough resistance to make the meter ring. Low and high-pressure switches are also safeties that look similar on schematics. The high-pressure switch opens when the pressure increases (the line is above the right circle on the schematic), and the low-pressure switch opens when the pressure decreases (the line is below the right circle on the schematic). If a pressure switch is stuck open, check the conditions that may have made it open (such as undercharge). Jump out the low-pressure switch and see why it went out on low pressure. Do the same to the high-pressure switch if it has failed (possibly due to failed condenser fan motor in cool mode, failed blower in heat mode, poor airflow in heat mode, or overcharge). In all cases where you encounter open switches, the most important thing you can do is find out WHY those switches opened. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Eric Mele investigates a miswiring issue on an older commercial McQuay system that has had a compressor replacement in the past. The surface-level issue is that the compressor runs and runs into a vacuum and doesn't shut off. Eric's first step is to investigate the controls, including the board, relays, pump-down switches, and more. Old McQuay units have separate compartments for fuses as well as controls and contactors for the compressor and condenser fan. In the case of this unit, Compressor 1 has been deactivated. After reading the schematics, Eric realizes that the safeties were tied into relay R5, and there could have been an issue with the low-pressure switch. However, that is not the case. After the system pumps down, Eric reads infinite ohms on the wires extending from the low-pressure switch. The next potential issue is that the incorrect wiring was used; the circuit should be incomplete, so Eric turns the deactivated compressor back on to see if the unit doesn't run (as it should) or if it starts and runs. When he turns the deactivated compressor back on, the unit starts and runs. Further wiring investigation leads Eric to an issue on wire 129; it goes to terminal 2 on the Centronic, but it should actually be going to terminal 2 on the motor protector module. Wire 129 was swapped with 120. After Eric replaces the wires, he starts up the unit after a time delay, and the compressor pumps down and shuts off as it should. Overall, the wiring was backfeeding power to the compressor all the time. Once the wiring was reconfigured correctly, the compressor stopped running and running into a vacuum. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan interviews Chris with A/C Easy Tee about a game-changing drain-cleaning product. The A/C Easy Tee is a PVC fitting that allows you to access the top of the drain line and easily connect a shop vac, hose, or source of compressed air for cleaning. With the A/C Easy Tee, you just need to use a straight fitting with a shop vac, and you can clean the drain pan. The product also comes with an angle tool to block a path to the air handler to force the water or compressed gases out to the end of the drain. Hose nozzles also fit in the Easy Tee. The Easy Tee differs from your typical 3/4" tee because it's mounted on the line differently and is a lot more functional as a result; the Easy Tee makes it much easier to access the upper part of the drain than a traditional tee and has a tapered design. However, it works well with two access points, including a traditional tee, to clean out the whole drain. Initially, A/C Easy Tee wasn't supposed to work on condensate pumps, but a pump adaptation has been in development. You can purchase the kit with the adapters, but you can also purchase tees individually at supply houses or in a contractor pack of 20. The tees are fitted with high-quality O-ring seals and are secure. You can purchase the A/C Easy Tee contractor pack on Amazon at https://www.amazon.com/Easy-Tee-Contractor-Pack/dp/B0752YWW1F/ref=sr_1_1?dchild=1&keywords=ac+easy+tee&qid=1597940882&sr=8-1, but you can also learn more about the product and company at https://aceasytee.com/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Franco D from DiversiTech tells us a bit about the Asurity product line. The Asurity line changes how we think about condensate management, and products include drain pans, condensate pumps, and drain treatments. The Pro-Treat line guard is one of the drain treatments on the market, and it stops bacterial zoogloea growth, which is a snot-like growth that happens to be a major problem in our Floridian market. The line guard goes into the condensate drainage system and is infused with silver and copper ions as well as a polymer to prevent bacterial zoogloea. To use it, you run the line guard through the condensate line and secure it in place with a zip tie. The DiversiTech lab tests have determined that the line guard may provide up to 20 years of efficacy, though real-world conditions have yet to be tested. Asurity also has a waterless trap, which is a trap that works on negative-pressure systems and uses the force of gravity on a ball inside the trap to block the hole on the inside. The Ultra condensate pump family of products has gone through many evolutions as technicians have given their feedback over the years. You can see into the Ultra tank so that you can determine the cleanliness without wasting time taking an opaque pump apart to realize that it was clean all along. It's also easy to handle this pump because it accumulates water in a depression at the bottom. Asurity also has a condensate pump pan, which creates redundancy in the condensate management system to have a backup system in place in case the main system fails. These drain pans must also be fitted with a switch to increase redundancy even further and reduce the risk of overflowing and damage. One other product we learned about was a quiet Undermount pump for ductless units. The Undermount has been designed to be as quiet as possible and aesthetically pleasing for units in plain sight. It is also very easy to clean out due to its accessibility. Learn more about the Asurity product line at https://www.asurityhvacr.com/ or DiversiTech in general at https://www.diversitech.com/en-US/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Scott Mieras from the Hilmor brand of DiversiTech tells us a bit about some feedback he received about the new Hilmor Lineset Cleaner. (As you know, we've been very excited about this product." After the demos at AHR, many people had questions about the lineset cleaner's efficacy on severe kinks as opposed to the relatively neat angles of the demonstration copper. In the demonstration at the symposium, Scott brought a demo rig with much more tightly kinked lines and showed that the pigs made it through just fine. He also added water to the system, and the pigs displaced it very quickly. "Pig" is the industry term for the plugs that you send through the line set, and the term originated in the oil and gas industry. They come in various sizes for different line set diameters. Even if the pigs don't make it to the other side, a blockage indicates that the line set has severe issues that need to be addressed. If a pig gets stuck, you can blow it out the other side and make it return to the starting point. You may also be able to use each pig multiple times if they don't suffer major damage on the first use. You can get the Hilmor lineset cleaner and pigs at many local supply houses. If you can't find the lineset cleaner or related accessories in your supply house, be sure to talk to the distributor and let them know that you're interested in the product and want it on the shelves. Hilmor will be selling the pigs in packs of 10 for each size. DiversiTech also has a new SWOOSH drain gun that was launched at AHR (the SG-2 double-barrel model). The SG-2 drain gun uses two 20g cartridges and offers 2.5x more volume at the same PSI as before. Another new Hilmor product is a portable sheet metal scoring tool. That tool allows people to create cross breaks in the field quickly and easily. Hilmor also has a reversible magnetic hex driver with easily changeable bits. It uses steel of the same grade as impact hex sockets in the field. The driver was developed with longevity in mind, and it has been tested as much as possible to make it strip-proof. Learn more about DiversiTech's wide range of products at https://www.diversitech.com/en-US/. Learn more about the Hilmor line specifically at https://www.hilmor.com/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan and Bert have a live conversation recapping the symposium and talking trade events

Eugene Silberstein, a co-author of Refrigeration and Air Conditioning Technology (RACT manual), joins the podcast to give us an introduction to psychrometrics. Psychrometrics focuses on the properties of air and its contents, especially as they relate to human comfort. To understand psychrometrics, we need to be able to quantify air: its weight, humidity, pressure, etc. We can do a better job as technicians if we figure out the air’s content and see how it relates to the CFM and overall unit performance. That way, we can have a more holistic view of HVAC performance instead of just focusing on adding or recovering refrigerant to improve performance. The psychrometrics chart helps us understand the conditions of the air based on quantities like water vapor, dew point, and more. The chart may intimidate techs, but it contains a wealth of information that can help technicians understand the air and the customer’s comfort better. Basic psychrometrics can also help us grasp why furnaces don’t actually dry out air; they pull the moisture out of the air and pull it back in, so the absolute humidity stays close to the same. However, we commonly add humidifiers because the relative humidity drops with the temperature rise. Eugene and Bryan also discuss: How air filters and blower motors interact with the air Things that affect the weight of air per cubic foot Humidifying air and its effect on the density of air High-pressure air moving to an area of lower pressure How latent heat works Pressure and the atmosphere Absolute vs. relative humidity Learn about ESCO’s e-learning network at hvacr.elearn.network/ and "Psychrometrics Without Tears" at https://www.escogroup.org/training/psychrometrics.aspx. ESCO also holds the HVAC Excellence Conference; learn more about that at https://www.escogroup.org/hvac/nhetc/default.aspx. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bert walks around and asks symposium attendees and speakers what they enjoyed most about the 3rd Annual HVACR Training Symposium at the Kalos HQ. We had speakers like Trevor Matthews, Ty Branaman, and Joe Shearer give presentations and answer questions on panels. Speakers and attendees alike were grateful for the opportunities to teach others, learn, and meet many new people from all walks of life. Although the training was the main draw to the symposium, most people seemed to enjoy the networking opportunities offered by the symposium. Many first-timers and repeat attendees alike came out to the symposium and had a great time. We were excited to hear their thoughts and are already looking forward to next year's symposium. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this live stream, we're talking with Joel... about why you need to get your virtual tickets to the HVACR Training Symposium... NOW! Visit https://hvacrschool.com/symposium/ for more information and to find the link where you can purchase your ticket. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bert teaches a class at Kalos on commonly occurring Heat Pump queries. These mainly include questions about refrigerant system in heat mode and what to expect in terms of pressure. Bert covers checking discharge line, liquid line and suction line in heat mode and the best way of setting charge during cold weather. Air flow has huge effect on heat pump when it's in heat mode. You need to be checking filter and whether your coil is clean outside. Bert also talks checking heat strips as well as replacing them and the whole heat kit. Bert ends by instructing the class to start with what they know first: the main rules of thumb, checking if the air filter is dirty etc. He also points out that if the house is not cooling the techs should find out why back up heat is not running. Please check out this class for more info on heat mode: https://www.youtube.com/watch?v=IoBiyEpaZAw&t=390s Also this is a refrigerant book that any tech should have: www.acservicetech.com/ac-book Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Brett Wetzel and Kevin Compass from the Advanced Refrigeration Podcast join us to discuss commercial rack refrigeration and identify components. In supermarket racks, we typically have anywhere from 2-5 compressors on a single rack (with multiple evaporators, metering devices, and sometimes even condensers). These compressors may come in several varieties (including screw and scroll) and be digital or have VFDs. They also have common suction and discharge headers. The compressors all share oil from a single system. Oil separators can come in three varieties: centrifugal, impingement, and coalescing (most efficient). The separator would feed into the reservoir, which stores oil. Many rack systems use several different valves. Check valves to direct the refrigerant flow, especially on heat reclaim systems and split condensers. In some cases, there is a three-way valve or a solenoid valve that controls or stops the refrigerant flow. LDR (liquid differential regulating) valves maintain the required differentials during defrost. Ball valves can be found all over a rack (liquid line, suction line, discharge line, etc.) and can isolate a line. Standard and balanced-port TXVs or EEVs may also appear on racks. There is also an EPR, which controls evaporator temperature and pressure. Grocery systems have a drop leg before the receiver, which stores liquid refrigerant. We want a full column of liquid leaving the receiver, which we can confirm with a sight glass rather than subcooling. Brett, Kevin, and Bryan also discuss: Reheat and excess heat Split condensers Drain leg/drop leg vs. liquid line Mechanical subcooling and heat exchangers Counterflow piping Hot gas vs. Kool gas defrost Standard vs. balanced-port TXVs Distributors Evaporator fin spacing Cleaning components Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

This video is a recap of all the cool interviews that Kaleb, Eric Kaiser, Leilani, and the rest of the HVAC School team did at AHR Expo 2022. Many of these were live-streamed on Facebook, so we've compiled them into a single video. Bryan stopped by the DiversiTech booth to make pigs fly in a tool demo (hilmor line set cleaner) with Scott Mieras. The cleaner uses compressed nitrogen to launch the pig, and the kit comes with 5 different nozzles for all sorts of line set sizes, foam pigs of varying sizes, and a catch bag. The pigs don't get stuck, even in some of the most kinked line sets. Learn more at https://www.hilmor.com/. Eric Kaiser spoke with Nick Bailey of Mikrofill, which is a brand of UK-based Stuart-Turner that is starting to make its way into the American hydronic and chilled water system marketplace. Mikrofill is a pressurization unit that fills commercial hydronic systems with adequate backflow protection. The Mikrofill units are wall-mounted and use solenoid and check valves to administer water to commercial systems until the water reaches a certain pressure. It also offers alarm systems to alert customers of fill levels and potential threats to normal operation. Learn more at https://mikrofill.us/. Leilani visited the NAVAC booth to speak with Kevan Mayer and check out the battery-operated swaging tool, which is quite similar to their famous battery-powered flaring tool. You can get these products soon from your local wholesaler or TruTech Tools. Learn more at https://navacglobal.com/. DiversiTech's SpeedClean product family had a new addition on display at AHR: a 360-degree bib kit that protects the entire mini-split, including the backside and the top to prevent ceiling and wall splatter. Learn more at https://www.speedclean.com/. At the ADEY booth, we learned all about corrosion prevention on hydronic systems. ADEY's cleaners remove magnetite and scale from boilers, which may reduce the likelihood of premature boiler failure. Some of ADEY's technology also includes MagnaClean filters and MagnaCleanse flushers with magnets that can catch magnetite. At AHR, ADEY unveiled the CMX, which has dual-filtration capabilities for magnetic and non-magnetic contamination. Learn more at https://www.adey.com/us/. Crowcon has recently entered the US market; it is a UK-based gas detection instrumentation company. We learned about their durable Sprint Pro combustion analyzer, which also serves as a manometer for pressure testing (up to 0.84" wc) and a sniffer for flammable gases. These combustion analyzers also have many protections, are Bluetooth-compatible for data display and storage, and are made of extremely durable materials to make them last a long time. Learn more about the Sprint Pro at https://sprintprousa.com/. You can also visit the general site to learn more about the calibration system and portable gas detectors at https://www.crowcon.com/. DiversiTech also held the Fastest Hands competition, which tested how quickly competitors could drill screws into a piece of wood with a DiversiTech nut driver. The competition was won by Yechiel of Prime Air in Spring Valley, NY. Brent Lammert with HIKMICRO and Bill Spohn showcased some small and affordable thermal imaging cameras. These cameras could replace infrared thermometers (and do a better, more accurate job). The cameras allow you to see the real severity of a problem, such as an overheating wire, in high resolution and at a distance. Learn more about training for these cameras from TruTech Tools webinars at https://www.trutechtools.com/Thermal-Imaging_c_1338.html. Learn more about HIKMICRO at https://www.hikmicrotech.com/en/. We also visited the Milwaukee Tool booth and learned more about the new jaw for the Milwaukee M12 press tool. You can use the tool combination to make tight fittings, though reaming the inside and outside of the pipe is recommended before making the fittings. We also looked at the M18 press tool, a compact threader, and a tripod chain vise. Milwaukee has also developed its mobile app to support tool data and theft deterrents for some added security. Learn more at https://www.milwaukeetool.com/. We stopped by the Santa Fe booth and talked to Nikki Krueger, who has spoken at HVAC educators' conferences and will be at the HVACR Training Symposium. The Santa Fe brand has expanded to include an umbrella of IAQ solutions like HEPA filtration and ventilation, not just dehumidification. Santa Fe also has an in-wall dehumidifier, which fits in the wall and is ideal for multi-family applications, storage facilities, and basements. Watch a case study with the MD33 dehumidifier on Corbett Lunsford's Home Performance channel at https://www.youtube.com/watch?v=aaiq7QzfW2g&t=149s&ab_channel=HomePerformance. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

This 3D video shows how low voltage wiring works in a typical heat pump system. We cover schematics, some electrical circuit basics, how the low-voltage circuit accomplishes its tasks, and some best practices to maximize the longevity of your low-voltage circuits. There will be three diagrams: the condenser, heat strips, and air handler each having its own schematics. Those schematics show various types of switches, including basic switches, pressure switches, thermal switches, float switches, and contacts. An open switch has no electrical path, meaning that the equipment can't turn on. On the other hand, a closed switch allows electricity to pass through, so the equipment can turn on. Switches will be either in the normally closed or normally open position, and the schematics will indicate the normal state of the switch. It's also worth noting that switches are power-passing devices and do not use or consume electricity. In the condenser, you will see high and low-pressure switches. The heat relay on the heat strips will have a prominent pair of normally open contacts. The air handler usually has a normally closed float switch, which opens when water fills it up and breaks the circuit. Compared to switches, loads are power-consuming devices that transform electrical energy into some other form of energy. The contactor coil and reversing valve solenoids are examples of loads. Within the thermostat, G (green) goes to the blower, Y1 (yellow) is for the contactor, O/B (usually orange, sometimes dark blue) is for the reversing valve, RH (red) is for constant 24v heat (RC is constant 24v cool), C (blue) is for common, and W2 (white) is for auxiliary heat. In this case, we are using ACC+ (black) for dehumidification. The transformer is the source of the 24v power that starts everything. Transformers take high voltage (often 230v) from the power company on the primary and drop it to 24v on the secondary, which then goes to the integrated circuit board. The primary and secondary interact electromagnetically; they don't actually touch. When the 24v power makes it to the integrated circuit board via SEC1 or SEC2, it passes through the 5-amp fuse and powers the R terminal on the terminal block. Due to that configuration, many techs wire the float switch to break R. Breaking R will stop power to the thermostat and the defrost board at the condenser. (However, some techs may break Y instead.) Y goes from the thermostat to the terminal block and then to the contactor coil. The contactor coil needs 24v to pull the contactor in and close the contacts that allow power to reach the compressor and the condenser fan. Y goes in and out of the high and low-pressure switches before reaching the contactor coil. W2 connects to the heat strips and W on the defrost board from the terminal block. So, either the thermostat or the defrost board has the capability to bring on electric heat. The G terminal supplies constant 24v power to the blower fan inside the air handler. Common feeds from the common side of the transformer and goes to the thermostat to complete the circuit. It then provides 24v common to the defrost board, which also completes the circuit on that side of the unit. We need common in all cases because it provides a path back to the transformer; otherwise, the circuits would all be open and would not work. The O terminal's wire passes through the terminal block from the thermostat. Then, the 24v power goes to the condenser to energize the reversing valve solenoid in cool mode. (Note: Ruud and Rheem systems energize the reversing valve solenoid in heat mode, and these may have dark blue instead of orange wires.) When we use ACC+ for dehumidification, the blower will only reach full speed when the DH terminal is energized on the terminal block. When stripping back the wire jacket, try to minimize nicks by making a small vertical cut and pulling the sheath back. Cut the sheath you've pulled back. Cut the tips of the conductors, as you may have nicked them. Make careful cuts to expose the bare conductors; you want them to be able to reach the terminal block or touch under the wire nut, but they shouldn't be exposed. When routing wires or cables through cabinets or other areas where they might get cut, be sure to use proper grommets. Don't run wires over metal objects like the capacitor, as shorts may occur. When routing the wires in a spot where they might chafe, rub out, or otherwise suffer damage, use a conduit whenever possible to protect the wires. Also, use zip-ties to secure wires with a bunch of slack. Short circuits happen when there is an undesigned path, and open circuits happen when the path is interrupted completely. Try to minimize both as much as possible. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Leilani visits the Noritz booth at AHR Expo 2022 and talks with James Facer, National Commercial Manager of Noritz America. James tells us all about the exciting tankless water heaters that Noritz is bringing to the market. The first tankless water heater that James covers is the NRCR (Noritz residential condensing recirculation). The NRCR provides unlimited, instantaneous hot water with its built-in recirculation pump. That sort of technology eliminates the need for installers to put in their own recirculation pumps to use with the tankless technology, so it reduces jobsite labor. Every component is designed for service and can be maintained or repaired with tools in most HVAC technicians’ tool bags. The NRCR is designed to be serviceable for its entire lifespan, comes with a 15-year warranty, and boasts an efficiency rate of 98%. Noritz also offers a combi boiler, the NRCB (Noritz residential combi boiler). The NRCB is a wall-hung combination boiler that can provide domestic hot water AND space heating out of a single appliance. It is also 95% efficient. A 35,000 sq ft 3-bathroom home can generally rely on just one NRCB for all of its hot water and space heating needs. As with the NRCR, the NRCB is designed to be easily serviceable. Noritz also has the EZ series, which works well for retrofit applications because it has plumbing connections up top. The EZ series units are also 98% efficient. On the commercial side, Noritz offers the NCC199CDV, which is its flagship commercial tankless water heater. It is possible to meet high water heating demands by cascading multiple water heaters with the NCC199CDV as the main tankless engine. The NCC199CDV also has a 10-year commercial warranty. Noritz also has hybrid solutions in its product lineup. The Hybrid Hot product attaches to a current tank, which recovers tank water and takes stress off the tank, which reduces the likelihood of leaks and may increase longevity. The total tankless solution comes with the TTS Synergy series. It comes in configurations ranging from 2 to 6 units for high-level installations. The TTS Synergy units have one point of connection with the facility, and the configuration can control the facility’s power, water, gas, condensate, and building recirculation with that single point of connection. The system uses an ECM (which modulates for maximum efficiency) and also acts as a storage unit for the water. Learn more about Noritz products, diagrams, and resources at noritz.com. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bryan has a live discussion with Chuck Allgood and Brandon Marshall with Chemours. They discuss what makes a great refrigerant and what to expect over the next few years, especially with changing regulations and the rise of HFOs and A2L refrigerants. On recent podcasts, we described some of the California Air Resources Board (CARB) regulations and how they paved the way for some of the regulations we will begin to see nationwide. Such policies include using refrigerants with less than 750 GWP, which necessitates a phasedown of high-GWP refrigerants like R-410A. As a result, California contractors may consider moving to next-gen products sooner rather than later. Many OEMs have started making systems that work with the Opteon refrigerant line, which is a series of HFOs meant to replace high-GWP HFCs. When creating a new refrigerant, Chemours has had to consider several factors, including performance (thermodynamic properties for capacity), toxicity, flammability, environmental properties, and availability of materials. Opteon HFO blends differ from R-32 in that they are blends (often containing R-32). As a result, Opteon blends have lower GWP than R-32 alone. A lot of future-proofing has gone into the Opteon line, so if R-32 is eventually deemed a "high-GWP" refrigerant in the future, the industry already has a replacement to fall back on. It also has discharge pressure advantages over R-32 but uses the same lubrication. Opteon refrigerants and R-32 are A2L refrigerants, so they can't use the same vacuum pumps and recovery cylinders as A1 equipment, and they can't be retrofitted. A2L systems may eventually have left-handed threads, which can help reduce confusion as to whether the refrigerant is flammable or not. A2L refrigerants are nowhere near as flammable as hydrocarbons like R-290 (A3). Precautions for A2L refrigerants are not the same as A3 refrigerants; static sparks likely won't cause the A2L refrigerant to ignite and will barely propagate flame under operating conditions. However, we need to take precautions that we didn't take with A1 refrigerants. A2L refrigerants are also significantly less flammable than A2 refrigerants according to several tests, so that was what warranted the new designation. (It's also worth noting that A1 refrigerants will propagate flame under extreme conditions.) Whenever we bring a refrigerant blend to the market, we have to think about glide. R-410A had minimal glide, only about 1 degree, so it was almost negligible. However, R-454B has glide around 3-4 degrees, so you'll have to use the dew point to set the superheat and do other best practices for blends. Learn more about the Opteon refrigerant line at opteon.com. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bill Spohn talks through his experiences with high-performance home building and MORE. He also answers some viewer questions at the end, especially about Testo instruments and NOX filters. Special thanks to Eric Kaiser and Kaleb Saleeby for making this podcast happen! NetZero HVAC is all about designing a system that works very efficiently and correctly with a tight home. NetZero homes use natural heating (from radiant heat), energy generation, and ventilation to generate as much or MORE energy than what would be consumed (minimizing utility bills as much as possible while maintaining high comfort standards). Many of these homes use solar technology to provide electricity, and a battery bridges the gap. These homes do NOT use natural gas on the property; they are all electric. In many cases, these homes are manufactured with a PHPP or personal home planning package. These PHPPs come with pick lists that allow you to choose materials that work for your home's ventilation needs and tradeoffs in design elements. Passive houses in multi-family modular buildings tend to be quite practical and relatively common. Building design software is very important for NetZero homes, as is precision in construction and reliable transportation. The construction needs to match the dimensions and specs of the drawings, especially in modular homes with factory-built units. In some cases, physical models need to be made to see how everything will work together as well. Manual J is important as are the more general estimates provided by the PHPP. Working with contractors and understanding building science are two of the most important mental characteristics that a person needs to build and design NetZero homes successfully. As the industry stands right now, more people need to communicate about NetZero HVAC before we can expect widespread adoption and knowledge of it. Bill Spohn also talks about the pricing and timelines of building NetZero HVAC homes. In his case, he used a highly customized design, but the builders managed to put it all together within a month (October 2019). Some extra building considerations included vinyl siding for the outside of the home and foam insulation thickness. The foundation was factory-made (with foam insulation) by a company that used to do parking lot decking. Bill's home uses electricity, including backup heat, but he intentionally leaves it off; backup heat is quite inefficient, and he opts to go without it in most cases. (Not to mention, the heating system can typically heat the home well enough without the backup heat.) The HVAC includes a high-pressure air handler and has zones. Of course, it wasn't perfect; the heat load wasn't correctly calculated for the main space, and the system tripped out on high head pressure while the other zones were closed. The SpohnHome also uses data logging to keep track of conditions that may impact safety and comfort, especially outdoor temperature and humidity as well as indoor CO2 and VOCs. The monitoring systems for HVAC, IAQ, and hot water don't consume much energy at all. When it comes to sizing, Bill's 2-ton inverter system manages to heat and cool his 4,400 sq. feet quite easily. So, his home and HVAC system combination proves that rules of thumb aren't always 100% reliable for all situations. Bill was fortunate enough to tour the factory and become acquainted with materials suppliers and builders along the way. Overall, he is generally happy with his home, but he has had some issues with radon. He also had to choose between passive house triple-pane windows and double-pane windows as he considered air infiltration/exfiltration and radiant gains. Overall, NetZero HVAC homes require a rigorous understanding of airtightness, solar gains, and ventilation, as those have major impacts on building performance. You can learn more by listening to Bill's podcast, Building HVAC Science. You can subscribe to the podcast on any podcast app of your choice or get an overview at https://buildinghvacscience.libsyn.com/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Chris Forth with Johnson Controls joins us for a live podcast at AHR Expo 2022. We discuss the DOE 2020 Transition and EPA 2025 Transition. Every 6 years, the US Department of Energy reevaluates its efficiency standards and has decided to upgrade its standards. (For example, the DOE decided that the North, Southeast, and Southwest needed different efficiency standards.) So, as these standards change, contractors need to pay close attention to changing efficiency standards as they stock equipment. Almost all OEMs are currently experiencing supply chain slowdowns, so contractors need to be ahead of the curve when it comes to ordering products on time to meet standards; some contractors may consider ordering 15-SEER units so that they can buy and install those units legally regardless of the installation date. Contractors would be taking a gamble by ordering a 14-SEER heat pump; it would have to arrive and be installed before the standards change. However, contractors may be able to sell more complete systems at this rate; they can sell more efficient systems and earn more on those installation jobs. The A2L phasedown requires us to phase down the production of high-GWP refrigerants, including R-410A. Most of the low-GWP R-410A replacements are A2L refrigerants, which are mildly flammable (nowhere near the same level as R-290 or hydrocarbons). We can expect new training related to A2L refrigerants and the rise of specialty tools, including A2L-compatible vacuum pumps. The A2L label means that a very small level of flame was propagated in testing; static sparks and indirect heat typically WON'T be a cause for concern. However, A2L equipment may come with sensors to deal with possible fire risks before flame propagation occurs. These refrigerants also tend to be very efficient, and the transition away from high-GWP A1 refrigerants like R-410A could be one that we can look forward to. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Kevin Hart with Haven joinsus to talk IAQ monitoring and HAVEN

We're excited to talk about a new lineset cleaner system by Hilmor that features pigs or plugs, not nitrogen or solvents alone. You can use the Hilmor lineset cleaner by itself or behind a solvent. The kit is neat, easy to carry, and comes with a thorough set of directions. You can insert the pig into the launcher, which comes with various adapters for many different tubing sizes. (We recommend reaming the edge before attaching the adapter to the line set.) We recommend using a new pig every time, especially if you use them behind chemicals. The pigs are very consistently manufactured, and they come in various sizes. They also come with a catch net, which holds the pigs on the other side of the lineset. You'll find that your lineset cleaning jobs are a lot more thorough when you start using the Hilmor lineset cleaner. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bert finds an interesting but commonly missed airflow issue when out to do a leak detection on an A/C system. Jessica also comes along for filming and to talk about tools. When the air handler is packed into a tight space, the front and back insulation can pull against the system. That insulation gets pulled against the blower, which can result in airflow problems. The solution to that sort of problem is to tighten down the insulation and keep it from flapping back up against the blower. To access the back insulation, you'll need to pull the blower wheel out. In this case, the washers are slightly bigger than the wheel and held in by three screws. When we remove the screws, the whole blower assembly can slide right out. Bert also comes across an upside-down screw with a very tight access space at the top between all the wiring and the relay. Making sure that the power is off, he gets the wiring out of the way to make the space a little less tight. When the screw comes out, Bert decides to leave it out, as four screws will work well enough to keep the blower assembly in place. The insulation looks pretty rough in the back, so Bert decides to glue it down on the flat sides and tape the corners. When taping the corners, Bert creases the tape BEFORE applying it to make the taping process easier. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Genry Garcia with Comfort Dynamics, Inc. explains why the way we do zonal pressure diagnostics is flawed. Zonal pressure diagnostics (ZPD) can create a misconception between customers and practitioners. The ZPD readings we get on interior rooms show a ratio between two openings: between the room and the rest of the house or between a zone and the outside. It doesn't tell you the size of the hole or the CFM50 of the leakage; a 25-Pascal reading would tell you that the holes are the same size, but it wouldn't tell you anything about the size of the hole or the extent of the leakage. Without knowing the hole size or the CFM50, a ZPD reading doesn't hold a lot of value from a technical standpoint. However, ZPD readings can be a decent piece of evidence for establishing that a client has leakage; these readings can help you close a sale and ultimately end up helping the customer. When using a blower door, you bring the space under -50 Pascals of pressure with respect to the outside. In Genry's video, he looks at an indoor laundry room with a supply and a return path through a vent that has been taken off. Under the first set of conditions, it would appear as though the laundry room is 84-86% connected to the outside, indicating a leaky room. However, when we open up the return hole a little bit, the pressure drops a lot, and it only appears to be 54% connected to the outside. However, we didn't affect the hole connected to the outside. So, the ratio is flawed. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bert teaches the Kalos techs about zone damper systems and how to work on them without being intimidated by them. Zone damper systems have a zone panel, usually near the air handler, where 24v goes in and 24v goes out. The zone panel controls the dampers, which can open and close depending on where we need to send the supply air; the dampers can close when we don't need to send air to a certain zone. We typically encounter damper motors of two designs: spring or power-open/power-close. The latter tends to be much more common in modern zone damper systems. A control system will have common, open, and closed terminals. A spring motor may have a wire run between common and closed; it doesn't need to be connected to the open control because the spring will open it instead of power. When the system is not calling, the dampers will be relaxed, so they will be open. Dampers also can't open or close properly unless the set screw has been tightened all the way down. You can typically get an idea of how well a damper is opening or closing based on how the air resistance sounds; if the damper is working properly, the sound will change a bit. When installing a damper motor, you need to know the orientation of your damper and make sure that the damper stops spinning when it's supposed to stop. The size of the damper rod also matters and tends to vary by manufacturer, so you need to pay attention to get the proper repair parts. Unlike the spring motor, a power-open/power-close motor will use common, open, and closed terminals. You can disengage the damper motor and see how freely the panel spins when you spin it yourself. If it spins freely, then you'd be able to rule out a panel jam diagnosis and could focus on the motor. Damper systems need to be powered by a different transformer than the A/C system's transformer, so you'll have two transformers. The air handler may connect to common (which is a ground) and the R terminal on the thermostat, but the damper system's terminals may connect to the actual damper system; common is NOT the same as on the A/C system. However, the staging on the damper panel needs to match the motor staging. Many damper issues can be understood without going into the attic. You can start one zone and check to see if air is coming out of the vent. Then, turn zones on and off as necessary to see which zones are and aren't receiving the airflow they need. Once you have an idea of the problem areas, THEN you can go into the attic. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Eric Mele explains how compound compression works on refrigeration racks. Compound compression works in stages and requires the use of refrigerant from the suction, discharge, and liquid lines to perform various functions. The first stage of compression is external; after the refrigerant goes through that stage, it gets pumped to the back of the compressor and then to the second stage of compression. From there, that compressed refrigerant goes to the discharge line and out to the header. Compound compression systems have a lot of piping. You may notice that suction lines come up and tee off at two compressor heads. There may also be piping that sends some of the refrigerant to other lines. One of those lines is a suction line from the subcooler, and the other is a liquid line that supplies the liquid injection for demand cooling. Both of those lines feed into the intermediary discharge line and use the expansion device element at the discharge line as a reference. (Not to mention, there are several solenoids along the way.) Racks rely on all of that piping to decrease the compression ratio and improve the efficiency of the rack. Racks with subcoolers will have liquid coming into and out of the subcooler; suction gas comes out of the evaporator side of the subcooler. The liquid goes to the compressor on demand to keep it cool. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bryan and Leilani cover all the exciting events on the agenda for HVAC School, including the 2022 AHR Expo in Las Vegas, the 3rd Annual HVACR Training Symposium at Kalos in Florida, the FRACCA Conference, and the HVAC Excellence Educators Conference. We will have our own booth at the AHR Expo, and you can talk with Bryan and Leilani, Nathan Orr, Danielle Wexler, Rachel and Eric Kaiser, Jessica Eagan, Kaleb Saleeby, and Jim Bergmann while you're there. Come visit us at Booth C6846, neat the HAVEN booth and the concession stands at the far right of Central Hall after you enter the building. Bryan will also be doing some podcasts and interviews at both podcast pavilions between Central and North Hall. The Sunday before the AHR Expo, we will be having a meetup at the Firefly* Tapas Kitchen & Bar (courtesy of Diversitech). All podcasts recorded at the Podcast Pavilions will be recorded and posted to the AHR website. HVAC School will be at both Podcast Pavilions during all three days of the event. Guests include Jim Bergmann, Andre Patenaude with Emerson, Ben Reed with HAVEN, John Pastorello with Refrigeration Technologies, Rick Streacker with Packard, and more. On the second day of the AHR Expo, Bryan will be moderating a panel discussing the state of the industry. They will be covering COVID-19, supply chain challenges, innovation, and more relevant topics. Panelists include industry experts from ASHRAE, AHRI, NAFA, NCI, and HARDI. Bryan will also be giving a presentation about preventing callbacks and warranty returns on the second day of the AHR Expo. His presentation will take a holistic approach to callbacks and warranty returns and be relevant to people in all segments of the industry, including distributors and manufacturers. The HVACR Training Symposium will be in Clermont, FL, and it will run from Thursday, February 17th to Saturday, February 19th. The symposium is a great place to connect with industry leaders and receive training from them. We also have a bunch of sponsors who will be showing off their products. Whether you attend in-person or virtually, the HVACR Training Symposium will also offer 16 NATE continuing education hours. Speakers giving presentations at the symposium include Ty Branaman, Jim Bergmann, Steve Rogers, Eric Kaiser, Genry Garcia, Bill Spohn, Rick Sims, John Chavez, Russ King, Ed Janowiak, Tony Gonzalez, Jordan Cummings, Sam Myers, Jim Fultz, Trevor Matthews, Jason Obrzut, David Richardson, Nikki Krueger, Joe Medosch, Don Gillis, Chris Mohalley, Craig Migliaccio, Rachel and Eric Kaiser, Rick Streacker, Alex Meaney, and Chris Stephens. We also have various roundtables on hot topics and some Q&A sessions. After the symposium, we will have a meetup at the Plant Street Market in Winter Garden, FL (courtesy of MeasureQuick). There will be free drinks for the first 70 people. We will also be at the FRACCA Conference from March 16-18 at the Florida Hotel in Orlando, FL. Bryan will be giving a presentation on vacuum with Jim Bergmann and will join his father for a presentation on ethics in business. HVAC School will also be at the HVAC Excellence Educators Conference in Las Vegas (at Southpointe) from March 21-23. Bryan will be joining Dick Wirz to give a presentation about educating people of various ages and life stages, and he will do a closing presentation of his own about attracting, recruiting, and training the next generation of technicians (mostly younger Millennials and Gen Z). If you have any questions about the symposium, please email [email protected]. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bryan takes a moment to talk about New Year's resolutions and how to focus on improving yourself all the time, not just making a commitment to grow once per year. Some of the most successful people have the mindset of being lifelong learners; they constantly learn new facts but also remain open-minded about updating their practices to make them better. Many of them cringe at the things they did 4-5 years ago, but that's okay! That's actually a good sign of significant growth. However, there are two things Bryan would advise staying away from in your career as an HVAC technician: having a victim mentality and feeling like a savior. In our careers, many of us have an expectation and feel entitled to that expectation. When we don't receive what we expected, we may feel like victims. However, that's not helpful to anyone and only fuels the vicious cycle of entitlement. Instead, try to avoid setting expectations for others and set expectations for *yourself* so that you will be able to handle the disappointments and unfulfilled promises of life in stride. (Ask yourself: "What will I do regardless of what my boss, coworkers, or customers do?") To avoid being consumed by the victim mentality, it's best to keep investing in who you are as a person instead of depending on others for your growth; always try to be a better friend, spouse, parent, or person regardless of others' promises and your life circumstances. It's also counterproductive to personal growth to see yourself as a savior or feel that being a savior makes your work worthwhile. Helping people, serving others, and doing work that matters is what we've signed up to do. People who want to be saviors want to be SEEN; being a savior is about recognition, not about doing good work. However, when you feel the need to be a hero all the time, reality will often not live up to that expectation, and it can be pretty depressing. Instead of focusing on what you are owed or that next dopamine hit you get from saving the day, it's more productive to focus on lifelong learning and self-improvement: reading new books, trying new tools, doing things you've never done before, and developing your internal character. When you develop your internal character, you can be confident in your work because you truly care and have good intentions, not because you want to be the hero. With self-improvement, we can hope to reach a point where our self-worth is not dictated by the emotions of others or external circumstances. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bert shows us how to do residential HVAC maintenance procedures the #bertlife way. Maintenance procedures allow us to build good relationships with the customer and get to know their HVAC systems. Before you even start the maintenance, you need to make sure you give a good first impression of yourself and the company. It's best to be courteous; walk on sidewalks instead of the lawn whenever possible and wear shoe covers before you enter the customer's home. When you communicate with the customer, ask them what they've noticed and experienced with their unit. It's best to do a visual overview of the system to catch problems early. In the case of the system in the video, Bert noticed that the line set insulation was starting to come apart and that the wire splices could have been improved at the outdoor unit. Since this video was shot in the fall, Bert turned the heat on to see how it performed and if any issues needed to be addressed before the cold season. Bert tested the heat strips and noticed that they were rated for 5 kW. Since the unit was a 5-ton unit, the heat strips were likely insufficient for heating the entire home in the winter. However, the heat was on at the thermostat, heat strips were working, and the heat pump was running correctly. Checking the reversing valve is another important procedure when maintaining heat pumps. Bert likes to start maintenance procedures with power-off checks and cleaning. That way, he can do the rest of the maintenance checkups and tests with a clean system and minimize the likelihood of leaving power off when he leaves. When cleaning a condenser, Bert likes removing the top. Removing the top allows him to check all the wiring, check the compressor terminals, and clean out the leaves and debris inside the condenser. Then, he sprays the coil with water from the inside out (for dirty coils, he uses Refrigeration Technologies Viper Venom Pack solutions). When cleaning the drain, Bert flushes a minimum of two gallons of water through the pan. Then, he pours two gallons of water down the service port directly. When the shop vac collects the water, Bert removes the top and analyzes the water to learn about the conditions inside the drain. Once again, visual inspections are critical on the indoor equipment as well to check for rubouts, poor connections, dirt buildup, and biological growth. After checking the blower wheel and evaporator, Bert also changes the filter, which is a procedure included in our maintenance program. The indoor coil is quite clean, so Bert uses a very small mild concentration of self-rinse Viper evaporator coil cleaner. He also wipes down the indoor electrical panels and everything he sprayed on. After cleaning, Bert turns the power back on and runs his tests. First, he tests to see if the float switch shuts off power when tripped. Then, he takes his air temperature split. Bert also checks the refrigerant charge; while waiting, you may decide to start cleaning up the job site and start preparing paperwork or final discussions with the customer. When closing out a job, make sure all panels are closed, everything is clean, the refrigerant caps are put back on. Clean up any messes you've made; you may also go above and beyond by wiping down the platform and doing other small, HVAC-related cleaning tasks that make the equipment look cleaner. Make sure the customer feels listened to and is aware of everything you've done and some potential recommendations to improve the system's performance. BEFORE YOU LEAVE, make sure the equipment is running and that the indoor unit is draining properly. Remember: a customer will only know if you did a good job if you have productive, positive interactions with them and if they can see how clean the unit looks. (Also, walking quickly is a good way to show a sense of urgency.) Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Corey with Kalos Services and HVAC School balances oil regulators and cleans the oil components on a Copeland 3D compressor on an R-449A parallel rack with an intermittent oil trip and demand cooling module. The compressor also has a Copeland Sentronic oil safety device. Before Corey begins cleaning, he needs to get as much oil out of the compressor and into the reservoir as possible. He does that by valving off the oil regulator and attaching a hose from the pump to the reservoir with the compressor ON. That way, the compressor uses its own power to pump the oil out and into the reservoir until it goes out on safety. When that happens, the M and L contacts on the Sentronic safety will have voltage; we can measure that voltage with a meter to confirm that the compressor has been locked out. Before Corey pumps down the system, he valves off the line feeding the demand cooling module and the King valves. Once everything is valved off, Corey and Chad move any additional gas in the compressor to the next compressor on the rack. They drain any excess oil at the bottom of the compressor. Then, they pull out the oil pickup screen and tube using a pick and clean those. Corey also pulls out the Sentronic sensor and demand cooling sensor, and he cleans those and sands the demand cooling sensor down. He then reinstalls the clean demand cooling sensor using Nylog as an assembly lubricant. After cleaning the oil components, Corey takes a vacuum pump and evacuates any additional contaminants from the compressor. Then, Corey balances the oil regulator using an OCV-5 check valve. He determines the pressure differential between the oil reservoir and crankcase suction pressure. After taking measurements and coming up with a differential of 5 PSI, Corey checks the manufacturer's graph to see how many times he needs to turn the check valve. According to the graph, he needs to make 10 counterclockwise turns to maintain a half-full sight glass. It takes some time for the oil to fill to the proper level, so we recommend waiting a day for the oil level to adjust after you balance the regulators. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Steve Rogers and Chris Hughes from The Energy Conservatory (TEC) teach the Kalos techs about total furnace airflow and explain how to use a precision manometer. Manometers have two ports. One port hooks up to a hose and reads the pressure in the duct, and the other port does NOT hook up to a hose; that port reads the room's pressure to provide a reference point for the other port. The pressure in the duct is usually higher than the pressure in the room. You can also use a manometer to measure the pressure differential between rooms if you put the hose into another room with the door closed and read the pressure of the air in the room you're occupying. Many HVAC technicians are used to reading pressures in PSI or inches of water column. However, nowadays, we have been learning how to use Pascals to measure pressures much more finely, thus increasing accuracy and precision in diagnostics. When measuring the airflow or static pressure on a gas furnace, you want to make sure the system is running at the highest cooling speed and that all the air is going through the main filter (no bypassing). You'll want to measure the static pressure by placing the probes in the supply and the return so that they can read the pressure drop. Then, the TrueFlow hood can measure the actual airflow in cubic feet per minute. In the first furnace system, we discovered that the static pressure was good but that the CFM was borderline low. We determined that the filter was likely causing the slightly low airflow. On the second system, the TESP was slightly high (with the supply plenum pressure being VERY high), and the airflow was too low. The TrueFlow app determined that undersized ducts or blockages were likely causes of these poor readings. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Steve Rogers and Chris Hughes with The Energy Conservatory (TEC) talk to the Kalos techs about airflow measurements. They also explain how to use the TrueFlow grid and app to help with commissioning. Airflow is important because we need it to be accurate to charge refrigerant properly, it’s crucial to homeowner comfort, and it can affect system efficiency. When the airflow is too low, less heat can be absorbed in the evaporator coil, which drops the pressure in the coil and decreases the refrigerant density. The compressor can’t move as much refrigerant if the airflow is too low. You won’t get proper air mixing, which makes it difficult for air to circulate comfortably for the customer. If the airflow is too high, the efficiency is good, but you can also get noisy ducts, reduce dehumidification, and run high suction pressure. High airflow is also uncomfortable for a lot of people, as they don’t want to feel air blowing on them forcefully. The TrueFlow app has four workflows: system airflow & static pressure, system airflow, blower fan airflow grade per ANSI/ACCA/RESNET Standard 310, and pressure gauge. Most A/C technicians can meet their needs by selecting system airflow & static pressure because you will get both of those critical values on the diagnostic screen. The system airflow is a fast workflow, but you won’t get the thorough breakdown you’d normally get on the first option. The RESNET 310 Standard is mostly for inspectors to check the target airflow. Finally, the pressure gauge allows you to take and record static pressure readings. You can connect the pressure gauge and TrueFlow plate to your mobile phone via Bluetooth. Then, you choose if you’re dealing with an air handler or furnace. You then select the airflow orientation and enter the cooling capacity, air filter location, and cooling climate. After you input the relevant information, you’ll receive a set of test instructions. During the test, your tools take 100 readings and give you an average value on the TrueFlow app. The TrueFlow grid replaces the filter during testing and takes readings where the filter normally is. It measures the airflow by taking a measurement similar to a duct traverse. With the filter in place, our test measured 563 CFM. A lot of math happens on the back end; the TrueFlow grid and app use a correction factor to predict what the CFM would have been with the filter in place. The diagnostic screen shows whether you have good, okay, or bad airflow and static pressure, and it shows potential problem areas that it has identified with the A/C system. It also shows the return static pressure drop and the supply static pressure. In our case, we had a very high supply static pressure. Overall, both airflow and static pressure were okay, with the former being a bit low and the latter being a bit high. In some cases, the static pressure and airflow issues may occur due to poor duct design. In our case, the TrueFlow app recommended checking to see if the supply duct is undersized, collapsed, or restricted. If a homeowner wants a copy of the results, we can send them the results and send pictures of the equipment through the TrueFlow app. The app automatically generates a PDF that you can send to the customer. The TrueFlow grid comes with an adapter plate that can help the grid fit in oddly sized systems. TEC has also been considering custom sizing options. However, when selecting a TrueFlow grid, the most important thing is that it measures the total airflow through the grid. The TrueFlow grid works regardless of the equipment’s cleanliness, but TEC doesn’t recommend doing static pressure tests with dirty equipment. In our second test on a different set of equipment, the TrueFlow grid picked up 687 CFM. Overall, the airflow and static pressure were both in the optimal range. However, if we wanted to improve a little bit, we could have addressed the somewhat high supply static pressure. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bert has been receiving some concerning calls lately, so he brings the Kalos techs together to address some common gaps in the technicians’ knowledge. For example, some techs who are already experienced enough to have their own van have been calling about voltage drop, but they were measuring voltage to ground instead of to the other leg of power. That indicates that they avoided that issue instead of addressing it and asking how to measure voltage properly. When technicians have a few gaps in their knowledge, those gaps may seem easy enough to avoid on most service calls at first. But when the gaps start increasing in number, it gets a lot harder to avoid those areas of poor understanding. Bert tries to tackle a common knowledge gap by teaching the techs about proper meter use. Voltage measures the potential difference between two objects. When you put the meter leads at two different points on the same wire, the meter will read zero volts because there is no difference between the leads. However, that doesn’t mean that the wire isn’t powered! Before you check anything electrical, it would be wise to do a safety check to ground; that won’t let you know if the equipment is working, but it will let you know that you have electricity. Many meter issues can be cleared up if you simply know where your power is coming from. You want to make sure that you have 240v (or 208v, depending on the application) making it to the motor. You can also check the relay and the contactor to make sure the electricity is going to the proper locations for running a condenser fan. Some systems, such as Lennox units, require the electricity to take different paths than expected; be mindful of that when you work on A/C units. Find out where the equipment wiring connects and check the voltage of that. Bert also covers pressure switches, which have been responsible for a few of those concerning calls lately. A spring forces two plates of metal together on a high-pressure switch, and that allows a path to form from one end of the pressure switch wiring to the other. When the pressure gets too high, the spring forces the electrical path open. The high-pressure switch is a normally closed switch. The refrigerant pressure must be high enough for the spring to connect the plates on a low-pressure switch. When the pressure is too low, the path remains open, so the low-pressure switch is a normally open switch. Even the most knowledgeable techs have gaps in their knowledge and need to contact tech support or do more research to solve a problem. There is no shame in not knowing something, but you would be better off addressing your lack of knowledge and learning something new instead of avoiding those problem areas and pressing on with your job. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Jesse leads a Kalos meeting about preliminary conversations, how to have them, and what they are supposed to accomplish. Preliminary conversations happen BEFORE the scope of work, whether you’re replacing a capacitor or doing a complete system replacement. On the service side, you’ll want to propose solutions slowly and set time, repair, and payment expectations. Make sure you communicate additional fees clearly and differentiate between the subtotal and grand total. You want to make sure that you and the client are on the same page. We also perform quoted repairs, which are more involved procedures but still require us to have diagnostic and financial conversations with the customer. The preliminary conversation is also the time to talk about warranties and clarify what the customer’s warranty covers (if applicable). Overall, we find that it’s easier to have money conversations before the exchange of value happens; if the conversation happens afterward, then you’d be more likely to experience challenges if the customer objects to the price. System replacements are huge and require lots of conversations before we arrive at the job site. The customer has already had money conversations with other people before the installers arrive. So, installers and techs need to do their homework on the system before they show up; there needs to be communication between the installers and the person who wrote the proposal to make sure there’s NO confusion about the procedure. We need to be educated on the system BEFORE we have the preliminary conversation. The preliminary conversation is also the time to confirm payment and make sure the customer is willing to pay with a check or credit card. The key to having a productive preliminary conversation is being prepared. By the time you get to the job site, you need to know what you’re doing and let the customer know what to expect on all fronts. We are taking care of the customer, and the preliminary conversation helps us start the long-term customer relationship on the right foot. Give the customer a chance to look at their entire system and ask questions about the procedure or the HVAC system in general. When we have those conversations about time, we need to plan for the worst. It’s okay if jobs take a long time if they’re supposed to, but we don’t want to underdeliver. Customers tend to worry that something has gone wrong if you take longer and expected. (Plus, the customers are happy when you finish ahead of schedule.) Remember: the goal of a preliminary conversation is to set expectations for the customer and communicate clearly. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bryan explains some best practices for installing a heat pump condensing unit in Florida. He walks through the installation process from the warehouse to the final inspections. The installation process truly starts at the warehouse, where we must make sure we have the correct unit and everything we need, including the concrete pad, heat strips, an appropriate circuit breaker, tubing insulation, UL-rated silver tape, and duct sealant. Some particularly Floridian components include duct board, hurricane straps, plywood, and corrugated tubing. When you get to the site, confirm that you have the correct unit type by looking at the existing unit’s tonnage, the new unit’s tonnage, and Manual J and S calculations. Then, you check the disconnect to see if it needs replacement before removing the disconnect and making sure you don’t have 240v between legs or between one leg and ground. Check the data plate to make sure you have the appropriate circuit breaker and wire sizing. Once you’ve verified everything, you can prepare for recovery. We recommend removing Schrader cores from both lines and using an inexpensive analog gauge manifold for recovery. Make sure you know the contents of your tank; if it’s empty, pull a vacuum on the tank to get the air out. Be sure to pay special attention to the water capacity (WC) and tare weight (TW) values on the tank, as you only want to fill the tank 80% for the refrigerant you’re recovering. When recovering the refrigerant from the old unit, some best practices include using a liquid line filter-drier and inverting your tank while recovering. Keep going until your recovery machine reaches or goes just below zero. After recovering the refrigerant, you disconnect the electrical components. When replacing an old heat pump with a new one, you may either reuse or replace the copper line set. If you reuse the copper, you would need to do pipe-wiping to remove residual oil and clean out the lines with a foam pig, nitrogen, and a hose. If you need to replace the copper, you need to expose the chase and make sure you have enough room to run new copper. In either case, you will need to cut the copper and must take measures to reduce contamination. We must also consider the drain. In Florida, indoor traps are uncommon, but they are industry standard. If you’re reusing the drain, you’ll need to clean it well; we recommend using water and a shop vac to clean the drain out well. Refill the trap when you’ve finished. If you place a new concrete pad or route a new drain, try to keep those two feet from the house, each other, the dryer vent, and your disconnect. When it comes to brazing new copper, the torch is critical to the success of the operation. Make sure everything is snug and that you turn out your regulators before opening the oxygen and acetylene tanks; try to keep the oxygen and acetylene both around 10 and 10. You’ll typically start off by opening the acetylene tank first, lighting the torch, and bringing oxygen in, but you could start to open both tanks around the same time once you get used to your equipment. You’ll want a neutral or slightly carburizing flame, not an oxidizing flame. When brazing, heat the copper to a dark cherry red color to draw the alloy into the joint. Allow the copper to cool, and route the copper lines as needed. Once you have enough of the copper line inside the home, you can start bending it with proper tools, sealing the chase, and using fittings or bent connections. When installing a new drain assembly, we put the sealant on the male end and hold the ends together. You only need primer if the system is pressurized. After you seal copper at the condenser, you can pull your Schrader cores out. When brazing the rest of the joints, be sure to cover the sensitive parts with a wet towel or Refrigeration Technologies Wetrag to prevent damage, especially indoors. Let each brazed joint sit for at least 20-30 seconds before cooling them off with a wet towel. Clean them and inspect them with a mirror. When your joints look good, you can do your pressure test. Use a spray-on bubble solution to check for leaks. Make sure there isn’t too much pressure decay over time. During the pressure test, you can work on your electrical connections and anchor your new condenser. Once you prove that you don’t have significant leaks, you can release the charge, check the thermostat wire, and assess your line lengths to see if you need to add any more charge. As always, you will want to inspect the entire system once it has sufficient charge and clean up your work. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Eric Mele explores a medium-temp supermarket rack that uses glycol, a secondary fluid used to help with heat transfer in chiller systems. Although we show glycol in this video, some racks may use CO2 as a secondary fluid instead. On the chiller side of a rack, the piping goes to the pump station and out to the store below. Chillers are actually quite similar to hydronic systems, as they have pumps and pump controllers. You can expect to see some spare glycol, electronic valves, and heat exchangers in the rack room on a glycol system. Heat transfer occurs in heat exchangers, where heat gets rejected from the refrigerant and moves to the glycol. These racks may also put discharge heat into the glycol. That heat can then be supplied to the reheat coil in the air conditioner or used for warm fluid defrost. When the rack puts discharge heat into the reheat circuit, it pumps the glycol using a circulating constant-volume pump, which helps the glycol go through the heating loop for the reheat coil. In the case of this rack, the lines go out of the rack at the bottom. Those lines run underneath the roofline and come back up into the A/C system across the rooftop. As with some other reheat coils, this system has a three-way valve to modulate the glycol flow through the coil. The rack may have another heat exchanger for warm fluid defrost. The discharge gas can warm up some of the return glycol coming back from the A/C reheat coil. That discharge gas can also go down to evaporators or cases that need defrosting. On the other side of the rack, we have the piping that allows the glycol to go down to the cases. There is also a three-way valve on the discharge line, which allows us to use discharge gas to heat water for use in the store. (These pipes have been labeled as "water heat reclaim." They lead to heat recovery tanks specifically for hot water.) Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Eric Mele shows how mechanical subcooling works on a rack refrigeration system. Mechanical subcooling allows us to drop the liquid refrigerant temperature even lower after it leaves the condenser. Upon exiting the condenser, the liquid refrigerant moves through the liquid line. In this case, the liquid line goes to a brazed-plated heat exchanger buried in some insulation. The liquid goes in one side of that heat exchanger and comes out the other side subcooled. On the other part of the heat exchanger, refrigerant flashes in the expansion valves. On this particular system, the cooling circuit comes from a different rack, but it may come from the same rack as well. The idea behind mechanical subcooling is to get more capacity out of the same amount of refrigerant. You can also put that load onto another rack. In this case, a medium-temp rack could benefit from better efficiency. (Note: if the other rack is struggling, you may cause the rack with mechanical subcooling to struggle as well.) Mechanical subcooling can also help counter the negative effects of long line lengths and improper pipe sizing. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Chad shows how to replace an oil filter on a rack refrigeration system. Chad starts by isolating the filter. He does that by closing the bottom of the oil reservoir. He then traces the lines to each oil level regulator and closes each one of those off. Drainage is the next step. Chad simply uses a hose and drains the oil into a bucket, which relieves pressure. He unbolts everything he can and loosens the mount. That way, he doesn't have to deal with the trouble of flare fittings. He then removes the old gasket and filter, cleans the oil canister, installs a new gasket, and puts a new filter in. Chad finishes off the procedure by tightening all of the bolts he loosened earlier. He also opens up the bottom of the oil reservoir and the oil level regulators at the compressors. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Eric Mele explains how oil works in parallel rack refrigeration systems. From the discharge line, the oil-refrigerant mixture goes into a large cylinder called the oil separator. As its name suggests, the oil separator removes the oil from the refrigerant; the filter may be inside the separator or beyond it. (In this video, the filter is inside the separator.) At the bottom of the separator, there is an oil float. From there, the oil moves through a pipe back to the oil reservoir. Some reservoirs, like the one in this video, have a sight glass before the inlet that allows you to see the oil going into the reservoir. There will also be some sight glasses on the reservoir that allow you to see the oil level inside the reservoir. From the reservoir, a pipe carries the oil to the oil regulators on each compressor. You can use those regulators to adjust the oil level for each individual compressor. These regulators usually also have a sight glass. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bryan teaches the Kalos techs about gas furnaces, especially 80% gas furnaces in Florida. They also do some hands-on training at the end. Furnaces use a flame, or the rapid oxidation of fuel, to heat the air. The furnace achieves combustion with a heat source, fuel, and oxygen. Furnaces may use one of two main fuel types: natural gas and LP (liquefied petroleum). Propane and butane are heavier than natural gas, so they are a bit more dangerous because they displace oxygen and fill the room from the bottom up. The furnace sequence of operation starts with a W call, which is a 24v call for heat on the W terminal (white wire). You don't want a G call because the fan would circulate cold air before the furnace lights, and we want to observe the flame before and after the blower starts. The flame should stay straight; if the flame wiggles a lot, you could have air leakage. Another potential cause of a wiggly flame is a cracked heat exchanger (which is quite uncommon in Florida). After the furnace receives a W call, the circuit board will check the inducer fan; under typical conditions, the inducer fan will start. (The inducer fan typically uses a shaded-pole motor.) Then, the pressure switch ensures that you have a proper draft. The pressure switch must have sufficient negative pressure in an 80% furnace. When you have a proper draft, you start the ignition sequence. After ignition, the gas valve opens. A flame rod or flame rectifier would prove that the flame is burning; if the flame is not burning, unspent gas could build up and cause an explosion. After everything has been proven, the blower will start up and move heat through the home. If any safeties can't prove air or flame, the furnace will shut off. We use four main types of ignition: standing pilot, direct spark (DS), intermittent spark (ISI), and hot surface (HSI). Standing pilot ignition requires us to light the pilot, and a thermocouple proves flame on the pilot light. Direct spark uses a spark to light the main burner. Intermittent spark ignition relies on a pilot that is NOT lit all the time; the spark igniter can also sense flame. The most common ignition type is hot surface ignition, which relies on a rod that heats up. Hot surface igniters are common fail items. The gas valve opens and puts gas in the main burner. When a furnace goes out on rollout, the rollout switches will open. High limit switches trip when the furnace gets too hot, which usually indicates low airflow. Natural-draft furnaces aren't very common in our Central Florida market, but we often see 80% non-condensing open combustion induced draft furnaces. The latter pulls air in from around the unit in the combustion air zone, so these units can't be stuffed in closets. The biggest dangers of gas furnaces are gas leaks, carbon monoxide, and flame rollout. Low-level carbon monoxide detectors can pick up carbon dioxide, and we recommend offering them to all of our customers who have gas furnaces. We prioritize safety over efficiency in our market, so we try to look for improper venting, poor gas line insulation (or other gas line leak risks), backdrafting or orphaned water heaters, improper gas pressure settings, high ambient CO during operation, CO in the home, and improper combustion air. Useful tools for working on gas furnaces include combustion analyzers, low-level CO detectors, combustible gas leak detectors, and manometers. You'll want to use your manometers to be aware of gas pressure and static pressure. You will use your manometer to set gas pressure (inlet AND outlet pressure), your personal CO monitor to measure ambient CO, and your combustible gas leak detector to check for leaks. You'll put your visual inspection skills to use on gas furnaces, checking for corrosion and other abnormalities. Check the surrounding areas, not just the furnace itself. When servicing gas furnaces in Central Florida, we start by checking and cleaning the burners. Then, we check existing CO monitors and advise customers about low-level CO monitors. We then inspect and clean the flame rod/sensor. After that, we inspect the venting and combustion air and check for gas leaks or improper piping. Then, we actually run the system and check the flame during operation. We then measure CO and gas pressure. We finally check the temperature rise. Bryan also covers: Fuel concentration Proving inducer air Pressure in the flue Gas pool heater ignition Gemini gas valves Inducer fan motor issues Backdrafting and water heaters Venting for high-efficiency furnaces Testing a flame rod/sensor Cold tanks Adjusting Gas Pressure on a Standard and Gemini Furnace Valve video: https://www.youtube.com/watch?v=d1L6Ut2pIYI&t=10s #Bertlife Gas Leak video: https://www.youtube.com/watch?v=d1L6Ut2pIYI&t=10s Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Eric Mele explains what evaporator pressure regulation is on rack refrigeration systems. He also explains why EPR valves are important for maximizing system runtime between defrosts. Evaporator pressure regulation helps us achieve 100% runtime between defrost. EPR valves can come in mechanical or electronic varieties. There is a mechanical EPR valve on the right side; you can adjust the stem of a mechanical EPR to set your evaporator saturation where you want. There is an electronic EPR valve on the left side; electronic EPR valves reference a temperature sensor and pressure transducer to maintain a constant temperature. A mechanical EPR will hold steady at the pressure you set, but the electronic EPR will modulate a little bit. However, for the EPR valves to work as they should, the suction pressure must be below the coldest evaporator at the main suction header. So, you’ll probably need a bit of wiggle room to allow for some variation in temperature and make sure the valves can operate properly. The overall goal of the EPR valves is to throttle the suction gas to control the evaporator pressure and maximize runtime by keeping constant, steady pressure on the load. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Eric Mele explains how defrost happens on rack refrigeration systems. The simplest form of defrost happens when we shut off the refrigeration for a set amount of time. This method works best on medium-temperature refrigeration. We rarely run medium-temp evaporators below freezing, so we can just let air move across the coil and get the ice off. Electric defrost is also common; we use electric heat outside the coil to melt the ice off in medium-temp or low-temp refrigerators. We can also use gas to defrost a refrigeration system, which is most common in low-temp refrigerators. The rack in this video uses gas defrost, and it has a solenoid valve for a defrost valve. We can either use hot discharge gas or with warm liquid, which is a Kool gas defrost. In either case, you’re bringing a warm fluid into the coil and melting ice from the inside out. During a gas defrost, you’ll shut off the suction line to the suction header. Then, you’ll open the solenoid and allow the warm fluid to flow into the suction line. The gas then comes back via the liquid line and into the liquid header of the running rack. You can trace the header back to determine if a rack uses hot gas or Kool gas defrost. In this case, we can tell that this rack uses hot gas defrost because we can trace the header right back to the discharge line. (It ties in right past the oil separator.) We can create flow back to the liquid header with a differential valve. That differential valve can be on the liquid line for hot gas or Kool gas defrost, and it may be on the discharge line for hot gas defrost only. The valve creates a pressure differential between the receiver side of the system and the liquid header side of the system. So, the liquid header will be at a lower pressure than the receiver, so the discharge line will be at a higher pressure than the liquid header. We can establish flow back from the high side of the system to our not-quite-high side of the system (the liquid header). Typically, the pressure differential will be around 20 PSI, but that number can vary with customer expectations and manufacturer specs. The hot gas defrost allows us to get some flow for our defrost while the system is still cooling. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bert teaches the Kalos technicians about gas pool heaters, which are less common in our market but still show up from time to time. Gas pool heaters use a gas-fueled flame to heat the pool, not a refrigerant that rejects and absorbs heat. However, like heat pump pool heaters, poor water flow will likely be the main cause of many problems you'll encounter. Gas pool heaters can burn either natural gas from a communal gas line or propane (if there is no communal gas line). You can look at the data tag to determine if you are dealing with a propane or natural gas pool heater. Some common fuel-related problems include empty propane tanks and air in the gas lines (from long periods of inactivity). When dealing with gas, you must pay attention to the minimum and maximum gas pressures on the data tag. If you're getting rollout issues or the heater isn't burning clean, check the inlet and outlet gas pressures; the safeties could be preventing the heater from working under unsafe circumstances. When you have successfully turned on your gas heater, the heater will try to prove that it has good airflow through its inducer motor. If your heater doesn't sense adequate airflow, it will trip the airflow safety switch (normally open). Sometimes, you will get an error code indicating that the heater isn't igniting. When that happens, you'll want to inspect the igniter and make sure you have gas going to the heater. You may come across hot surface or intermittent spark ignition in gas pool heaters. The next safety element is the flame sensor, which merely proves that the flame is active. You must make sure it is clean enough to sense the flame and close enough to the flame to touch it. Heaters typically try to prove flame within three seconds of opening the gas valve; if the sensor fails to detect a flame, everything should shut off. In Florida, gas pool heaters commonly rust out due to the climate and corrosion. We don't want to fix those units if they are so rusty that they are unsafe. In that case, we must communicate the safety hazard to the customer and quote them for a replacement. After the heater has lit and proven flame, there are a few more safeties that can halt operation. Anything related to the airflow may be clogged with animal or insect debris. If the airflow is poor, the heater will get hot, and a safety component should shut it off. Stack flue sensors work like water temperature boards and can let you know if the sensor is failed or if you have an actual problem. Limit switches go in the water and open when the temperature exceeds their rating; however, these can rust out easily or may fail due to recurring water issues. Poor water flow doesn't mix well with flame; the water may even boil inside the heat exchanger if the flow is poor enough, and the heater can start shaking due to the high pressure. However, we have safeties and backup safeties to open bypass valves or take other measures to prevent explosions. When it comes to electrical problems, the main issue will be animal activity; rats, insects, and lizards may get inside the panels and damage wires. Sometimes, you may encounter issues with controls that you're not familiar with, or you may be stumped by a gas heater problem. In those cases, manuals and tech support can be excellent resources. Before you finish, make sure you check the functionality of the heater in the EXACT same way the customer will use the heater. Here are some of the gas pressure measurement videos Bert references: https://www.youtube.com/watch?v=d1L6Ut2pIYI https://www.youtube.com/watch?v=xgZQmaE4HFA https://www.youtube.com/watch?v=rhNn3jYUjWc Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Eric Mele gives us an overview of a parallel rack refrigeration system. He shows and describes the components of a grocery rack. Parallel rack refrigeration systems have multiple compressors that are all tied together in parallel. So, the discharge and suction are all tied in together. Each compressor’s discharge line will drop down into one main discharge line. That main discharge line has an oil separator, which returns the oil to the reservoir and allows the refrigerant to proceed to the condenser outside the rack room. The refrigerant liquefies in the condenser and comes out via the liquid line. Refrigerant in the liquid line goes to the receiver, which is located underneath the compressors in this system but can be remote as well. The refrigerant then goes through the liquid line drier and to the remote liquid header. The liquid goes down to all of the cases and loads beneath the rack room, which are often walk-in refrigerators (where the heat absorption happens). Behind the liquid header, we have suction lines with EPR valves. These EPR valves are electronic, which regulate the suction gas to achieve 100% runtime between defrosts. The suction lines all tie together into a common suction header, which then ties into the suction side on each compressor. The oil separator and reservoir are critical components of rack refrigeration systems. The oil reservoir must be able to supply oil across three (or more) compressors. Overall, the goals of a rack refrigeration system are to keep compressors running as long as possible, share the refrigerant charge, share the load, and try to achieve 100% runtime between defrosts. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

In this interesting condenser fan issue, we noticed that the condenser fan seemed weak and was blowing cold air. Although we suspected that the compressor may have had an issue, we realized that one of the contactors hadn’t been pulled in when we opened up the panel on the condenser. It was a shunt, so we powered up one side and used meter leads to determine that the contactor itself was working fine. We already checked the capacitor before the video started, and we had 4.9 microfarads on a 5-microfarad capacitor. The compressor drew less than 1 amp (0.6, 0.4, etc.). Our meter picked up 1.1 amps on the fan wire. All of the components seemed to check out, so we determined that the fan was backfeeding into the compressor because of the shunt. We disconnected the power, discharged the capacitor, and found the resistance to ground. Overall, we determined that the condenser fan issue was due to the compressor backfeeding as a result of the shunt. So, that’s why the fan was running without the contactor pulled in. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bert teaches the Kalos techs a bit more about pool heat pumps. He expands upon the pool heat pump components that we don’t see on A/C systems, especially heat exchangers. Heat pump pool heaters operate on a refrigeration circuit, just like A/C units. They work like normal A/C heat pumps running in heat mode. Inside your pool heater, you have a heat exchanger with water coming in and going out. There are also two copper lines going in. Superheated, cool refrigerant gas goes into the compressor. After it’s compressed, it goes through the heat exchanger and heats the water. The heat rejection to the water causes the refrigerant to desuperheat and liquefy. Then, it goes through the liquid line (½”, not ⅜”) and into the TXV. After the TXV, the cool liquid refrigerant goes into the evaporator, where the cycle continues afterward. As with A/C systems, TXV replacement is a common issue on pool heat pumps. Every pool heater has a heat exchanger. Some heat exchangers have water hookups going in and out with refrigerant lines running within. Regardless of the form, heat exchangers all have the same function: to reject heat to the water and act as a condensing unit. Heat exchangers can crack and leak water. In those cases, you can expect the culprit to be severe versions of water flow issues, high pressure, the safeties malfunctioning, or high-temperature conditions. Water can only get into the copper lines through a heat exchanger crack (with blown-out copper). However, heat exchangers are pretty durable, so cracks are rare problems. When heat exchanger cracks do happen, the repair project is usually very labor-intensive. You may be better off quoting for the entire heater. If you quote only the heat exchanger, you will want to test the entire system; you will want to find out what happened to cause the heat exchanger to crack. Pool heaters also have thermostats, thermostat probes, water temperature, and pressure switches. Water pressure switches are very similar to float switches in their wiring; if 24v comes in and 24v goes out, the heater will know that it’s okay to run. If there is a flow issue that prevents the heater from running, you will see an error code like LO or FLO. Some older heaters may have float switches and pressure switches in the same circuit, and you can figure out if something’s wrong because the pressure switch can open and kill the power. You can ohm the components out with the power off. Clogged filters can also trip pressure switches. (You will also want to install pressure switches after the filter.) You’ll likely be replacing low and high-pressure switches more often on pool heat pumps than normal A/C heat pumps. It’s also poor practice to quote a switch without finding the issue that caused it to open. R-22 switches and R-410A switches have different pressure limits, so you will want to make sure you read the pressure ratings on the switches. When you have a pressure issue on a pool heater, it should NOT be your first instinct to add refrigerant right away. Pressure can fluctuate a lot with temperature differences between the pool and spa, and pool heaters tend to be sensitive to refrigerant charge levels. Try to find out why your pressures are high or low; if your pool temperature is cool but you have high pressures, then the pool heater might be overcharged. A heater will have two thermostats: one for water, one for defrost. The only defrost function is to shut the compressor down but leave the fan on when enough ice builds up. Defrosts tend to be quite long and inefficient, and pool heat pumps don’t generally work very well in ambient conditions below 50 degrees Fahrenheit. If you need to check your water temperature split, keep in mind that the bottom of the pool is cooler than the surface. You’ll want to read the temperature as close to the base of the pool as possible. Also, be sure to check the pump timers. The timers may not be running long enough to heat the pool sufficiently. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bryan teaches the Kalos technicians about electric heat, often used as supplementary heat in heat pumps and furnaces. He also shares some stories from the field and teaches the techs a bit of math. Heat strips are one form of electric heat. It would stand to reason that taking a bit of heat strip off wouldn't hurt anything, but the electric heat would be less effective. However, when you factor Ohm's law into the equation, you'd be taking off part of the heat strip and reducing the resistance, meaning that the amps will increase. Heat strips also burn out when they touch another piece of metal, like the casing around it, because the amp draw becomes much higher. Electric heat has some benefits, including its consistent BTU output (3.41 BTUs per watt); regardless of the outdoor temperature, you can expect the same BTU output all the time. It is also reliable and usually easy to work on. However, it is inefficient. Electric heat is the baseline of COP (coefficient of performance), and a pool heat pump that has a COP of 3 is three times more efficient than just the electric heat. Electric heat has other issues, including odors or smoke when it first starts after a long time of inactivity. (It's easy to burn off the heat strips on a PM, especially if you jumper W to R or use the thermostat to burn off the heat strips.) Electric heat also causes high bills when it runs too much and causes stress on the electrical service. Electric heat elements also draw very high current, so you have to manage your wire sizing and electrical connections. You can also encounter mistakes with blower interlock; you don't want to run the heat strips without the blower running. In a 4.6-kilowatt (5kW) heater, you would divide 4,600 by the unit's rated voltage to get the amps of electric heat. The wattage decreases when the voltage decreases because of Watt's law. When you put more voltage (electrical pressure) on the circuit, you get more current. So, the total watts would decrease if volts or amps were to decrease. If you divide the watts by voltage, you can find out your amps. To find the BTU output, take the watts (volts x amps) and multiply them by 3.41. You can also use Ohm's law to find the resistance. Take the voltage and divide it by the amps to get the resistance (ohms). The voltage is a moving target, but resistance stays constant for the most part. The data tag should tell you the proper wire size to feed the air handler; look for the MCA (minimum circuit ampacity) to help you make your decision. Keep in mind that 5-kW heaters are not necessarily 5 kilowatts. When it comes to terminals, you have W, W1, W2, W3, and E. W is just heat; it is usually just for a single stage of heat. W1 means first-stage heat; it indicates the compressor with the reversing valve de-energized. W2 means second-stage heat and can refer to electric heat. W3 is the next stage of heat, and E is just for emergency heat. We used to have to jumper Y1 and W1 and a few other terminals together on older thermostats; they perform similar functions, but the reversing valve would distinguish heating from cooling. When testing heat strips, you can usually (but not always) expect 5kW heaters to draw 20 amps and 10kW to draw 40 amps but still 20 amps per strip. However, the way you read the amps can change based on the voltage (230v vs. 208v). Commercial buildings often have 208 volts supplied to them because they are hooked up to two of three power legs. Heat strips also have thermal limits; therm-o-discs can be found on the high and low sides for extra protection. These discs also have temperature ratings on them. You can tell if the thermal limits are open by ohming them. If they are open, you'll measure OL or infinite ohms. If they are closed, the ohms will be low. To control the electric heat, a unit will have either a contactor or a sequencing relay. Sequencers have contacts that close at different times. You don't want to use a 90-340 relay, but we sometimes use those for a fan interlock. When using a 90-340 for the fan interlock, you must set it up correctly as not to melt the relay; the current from the heat strips should not go through the relay at all. To avoid confusion as much as possible, follow the wiring diagram and think of the relay as upside down. We can also stage heat strips if we have more than one. Staging makes the unit draw lower inrush current and use less electric heat (the less you use, the better). When testing heat strips, you can use three methods: measure the heat strip amps, test on and test off, and force the system into defrost to test the heat strip amps. Heat pumps with supplementary heat may have special code considerations when wiring to the outdoor thermostat, which you must keep in mind. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

This video stems from an HVAC School podcast episode where Trevor Matthews of Emerson and Bryan discuss Copeland reciprocating CS compressors. Throughout this video, Trevor and Bryan refer to Bulletin AE4-1433 (which you can find at https://webapps.emerson.com/online-product-information/Publication/LaunchPDF?Index=aeb&PDF=ae1433.pdf) as they look at the operating envelopes for the CS compressor. The CS compressors are hermetic reciprocating compressors that can work with some of the newer refrigerants. You will likely see these compressors in applications with smaller tonnages. You’ll usually want to charge these compressors with liquid refrigerant. If you have more than 6 pounds of charge in the system, using an accumulator is recommended. Under those charge conditions, the system also needs a check valve between the receiver and the condenser. Suction line pressure drop is one of the most important things to pay attention to in the system. Make sure the suction line is of an appropriate size, that filter-driers don’t have restrictions, and that accumulators aren’t clogged. Overall, many manufacturers recommend removing the duction driers to keep the pressure drop minimal. The recommended runtime for these compressors is also very short, only 5 minutes. CS compressors should cycle no more than 12 times per hour, and the off-time between cycles should be a minimum of 10 seconds. Before returning or replacing a compressor, make sure you check all of the electrical components, including the capacitor. If the compressor hums but has power, you could simply have a capacitor or potential relay issue. Trevor and Bryan also discuss: Return gas temperatures Discharge line temperature Compressor superheat and flooded conditions with refrigerant blends Crankcase heaters Pump-down recommendations to stop short cycling Initial charge vs. recharge Metering devices Line sizing Electrical shorts Sticking relays Single-phase vs. three-phase power Megohm testing Purging with and flowing nitrogen Burnout cleanup procedures Locking/tagging out equipment Hard start kits, potential relays, and start capacitors Check out our handy calculators HERE. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bert teaches the Kalos techs about pool heaters, how they work, and common issues techs can expect to encounter when they service pool heaters. When testing a pool heater after installation, you want to use it the same way a homeowner or guest would use it. If your controls haven't been set up, nothing will happen, so you need to make sure you turn on the heater the same way that the homeowners or guests do it to make sure it works. Configure the controls in a way that will fit the customer's usage. To do that, read the manual and look for the section about the external control. You'll get a description of the two types of controls: two-wire and three-wire. We use the two-wire configuration on more advanced external control systems; it has its own thermostat, and the customer sets the temperatures from the external control. The manual should explain the process of setting up the controls in detail. The three-wire configuration has the heater send a signal and allows that to determine if the heater is in pool mode or spa mode. If the heater receives the signal back, it's in spa mode; if the other terminal receives the signal, then the heater is in pool mode. Programming is required, and you must test these modes. When servicing a pool heater, think about what a customer interacts with. Make those areas your priority so that the customer can notice your work. Since not all contractors service controllers and The most common pool heater issue is related to water flow (though temperature sensors and capacitors present problems quite often). In many cases, installing a pool heater with a bypass valve. When the valve is not in use, the water can bypass the heater. However, issues with the bypass can lead to low water pressure. The water pressure switch can usually stop the pool heater whenever it detects a change in pressure due to a flow issue. When dealing with these problems, you need to know the flow direction, basic valve operation, and what to expect when looking at a pool and spa with water flow. The pool will often have two drains, and the spa will have one. The drains go back to the pump. Water flows straight up the pump and to the filter. To access the pump, take the filter cap off and access the filter. Take the filter off and see how the water runs. If the pool heater works fine, then you likely had a filter problem. So, the water goes from the bottom of the pool and into the sight glass of the pump. Beyond the pump, you have the heater. Out of the heater, the water will go to the bypass valve or another protective component before the chlorinator. Then, there is a three-way valve that goes into the ground and feeds the jets of the spa or pool through valves. There are both return and supply valves. Supply valves supply the pump (like the return in A/C), and return valves supply the pool jets with water (like the supply in the A/C). Pools also have a skimmer, which draws debris from the very top of the water. If the water level goes down, the skimmer will only draw air, which also indicates an issue. Very rarely will you turn a dial to fix the issue, but this is one of those cases. You can also see wire issues in the controls that have been poorly installed or misused. These issues include broken wire connections (overtightened) or torn-up wires between the heater and the control system. Don't stop yourself short of fixing a problem area for the customer just because your company may not specialize in controls; these types of controls issues are easy to fix. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bryan teaches the Kalos techs about charging and testing heat pumps in heat mode. He also covers rules of thumb that may or may not help you test heat pumps in heat mode. When connecting to a heat pump in heat mode, you will connect your low side to the common suction port. That port is located between the reversing valve and the compressor on the suction line, which will always be the suction line regardless of operating mode. The line between the air handler and the reversing valve is referred to as the “vapor line” regardless of operating mode; it can serve as either the suction line or discharge line. You also can’t leave your high side connected to the expansion line in the heat mode on some systems due to the placement of the metering device. Start your heat pump jobs by looking at the entire system, starting with a wide scope and narrowing your focus as you inspect the system. If there’s any frost on the outdoor coil, make sure you get it off the coil before taking any measurements. You can get rid of the frost by running the system in cooling mode, as the system will take its indoor heat to the frozen outdoor coil. While you want to avoid using rules of thumb whenever possible, you can use heating check charts if the manufacturer has them. You can use heat mode’s low-ambient heating check guidelines when the temperature is below 65 degrees outside. When it’s cold outside, your suction pressure drops, so you could mistake a system for being flat when it’s actually fine if you check it in heat mode while it’s cold outside. The suction pressure typically stays about the same as the outdoor ambient temperature, which is more of a fluke than anything else, but it’s still a decent rule of thumb. Another rule of thumb is that the condensing temperature should be 30-40 degrees above the indoor dry-bulb temperature. When the outdoor temperature drops, the suction drops. When the suction pressure drops but the indoor temperature stays the same, the condensing temperature may change only a little bit, and the head pressure will stay close to the same. That’s where we can get higher compression ratios and reduced capacity. Where possible, it is a good idea to test heat pumps without gauges in heat mode. However, you need the outdoor temperature to be between 65 and 15 degrees Fahrenheit and a frost-free outdoor coil. The suction line should be 5-15 degrees cooler than the outdoor temperature, the liquid line should be 3-15 degrees above the indoor temperature, and delta T indoors can vary wildly. Using the FieldPiece charging jacket, the techs waited until the difference between the high and low side pressures was between 160 and 220 for the R-410A Lennox system. Then, they checked the target subcooling. The heat pump needs to defrost itself from time to time because the evaporator coil can freeze when the temperatures get below 30 degrees Fahrenheit; the heat pump can’t absorb heat from the outdoors when the outdoor coil freezes over. The heat pump can give off steam in defrost, which looks like smoke and can alarm the customer. Heat pumps can also scare homeowners because they make weird noises in defrost. The defrost board can usually detect when the coil is ice-bound. The two main defrost strategies are demand defrost and time/temperature defrost. Demand defrost looks at air and coil temperature to find trends that surround ice-bound conditions. The time/temperature defrost uses a temperature sensor and time to determine when to go into defrost. During defrost, the system shifts itself into cooling mode, shuts off the condenser fan, and turns on the heat strips. Electric heat strips are quite inefficient, but it can be difficult to compare the economic benefits between electric and gas heat because of the changing cost of gas. Bryan also discusses: Reaching the limit on the manifold gauge Metering device pressure drops Switching to cooling mode for testing Lennox’s recommended procedures with the FieldPiece charging jacket 100 degree over ambient discharge rule Head pressure, CTOA, DTD, and coil size Running lower airflow in heat mode Compressor noise Old defrost detection methods Jumpering out defrost thermostats Inverter-driven and ductless technology Climate zones and complex comfort solutions Gas furnaces in Florida Fuel oil furnace drawbacks Burning off heat strips during fall PMs Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bryan weighs in on the idea that furnaces dry out the air than other HVAC technologies. He also explains what happens when you oversize a furnace and gives his opinion on the practice. When we talk about “dryness,” we must distinguish between low relative humidity (%) and low absolute moisture content (in pounds or grains of moisture). Raising the temperature of the air doesn’t reduce the amount of moisture in the air, but it does reduce the total percentage of humidity in the air. Relative humidity compares how much humidity there is in the air to how much there could be (100% or saturation). Warm air can hold more moisture than cold air, so cold air is “drier” than warm air in terms of total moisture content even when the relative humidity is high. For comparison, think about a shot glass that’s 85% full vs. a half-full 64oz Big Gulp; you’ll have a lot more liquid in the 64oz Big Gulp (hot air) even though it’s less full than the shot glass (cold air). A furnace takes the cold air and merely warms it up. All the original moisture is still there, but the furnace has decreased the air’s relative humidity percentage; the warmer air can now hold more moisture before it becomes saturated. The furnace doesn’t “burn” moisture out of the air and dry it directly, but the occupants of a building will feel their mucous membranes and noses start to dry up. Humidification strategies are sometimes needed for maximum comfort. Forced-air systems are likely to bring in outside air, which is likely to introduce dry air to the indoors. (That is especially true if the furnace brings in some of its combustion air.) Forced-air systems also heat the air quite well, but it doesn’t necessarily heat the objects in the space. Conversely, radiant heaters heat the surfaces and people in a space much more evenly, meaning that there will likely be a lower impact on the humidity. When it comes to oversizing furnaces, the idea is that you could dry the air out more because you’re moving more air. However, you’re also likely to experience more leakage, which could increase the amount of dry air coming in as well and give you less control over the humidity. Overall, we recommend using properly sized equipment or radiant heating strategies for the most control over the humidity in the space. Of course, that goes along with proper sealing the ductwork and utilizing sealed combustion to bring combustion air into the space. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Kalos tech Jessica uses the AccuTrak VPE-GN Ultrasonic Leak Detector kit to locate a leak in the field. The kit comes with the leak detector (with a "gooseneck"), noise-canceling headphones, and the product manual. The A/C unit featured in the video is a 5-ton Carrier system from 2003. Jessica does a visual inspection first. The A-coil shows some signs of galvanic corrosion and has a few spots that feel oily to the touch. Oily spots may indicate leakage, so Jessica marks those up and knows to check them later. Per the manufacturer's recommendation, Jessica starts checking for leaks by spraying the coil enough to make it damp. Then, she sprays some Big Blu on the coil to see if bubbles form. Sure enough, some microbubbles begin forming on the spots that Jessica marked. After that, she uses the AccuTrak VPE-GN Ultrasonic Leak Detector to confirm the leak, and it worked very well; Jessica compares its effectiveness to the Bacharach H-10 leak detector. The AccuTrak Ultrasonic leak detector is not a traditional "sniffer." Instead of sniffing for traces of refrigerant, the Ultrasonic leak detector detects escaping nitrogen, which occurs naturally in our air. As such, you can use these leak detectors on systems without refrigerant; you'll still locate leaks. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

This video stems from the HVAC School podcast where Jason Obrzut discusses A2L refrigerant facts. Jason is a member of AHRI’s Safe Refrigerant Transition Task Force and author of the RACT manual. To learn more about A2L refrigerants, check out the AHRI Safe Refrigerant Transition Task Force’s webinars, newsletters, and fact sheets at https://ahrinet.org/saferefrigerant. Since the release of the podcast, the EPA has released its ruling on the HFC phase-down. Learn more by visiting the EPA's site and checking their resources on the ruling at https://www.epa.gov/climate-hfcs-reduction/final-rule-phasedown-hydrofluorocarbons-establishing-allowance-allocation. You can also check out the official EPA fact sheet at https://www.epa.gov/system/files/documents/2021-09/hfc-allocation-rule-nprm-fact-sheet-finalrule.pdf. ASHRAE designates refrigerants into categories based on toxicity (A or B) and flammability (traditionally 1, 2, and 3). So, the new A2L designation indicates that a refrigerant is relatively non-toxic but has a flammability value between 1 (low) and 2 (moderate). While propane (R-290) is a good refrigerant because it is natural and has low toxicity, it is very flammable (A3). Future refrigerants will likely fall under the A2L designation; the mild flammability will probably be the tradeoff for efficient, low-toxicity refrigerant with a low environmental impact. However, A2L refrigerants cannot be vented, even despite their low GWP. We also cannot use these refrigerants in retrofits. A2L refrigerants will likely become much more prevalent around 2023 as HFC refrigerants phase down. The phase-down period will be specified shortly, and it will begin with a 10% reduction; the specific parameters of the phase-down have yet to be set. When working with A2L refrigerants like R-32, you can expect little to no change in how you work on equipment if you’re already employing the best practices. Sizing and capacity will hardly change in the residential market. In the commercial sphere, these systems still look and operate quite similarly to current units. Jason and Bryan also discuss: Refrigerant detection systems (RDS) Flowing nitrogen and other best practices Non-A2L HFC alternatives Left-handed threads Non-standard safety practices R-32 properties Refrigerant glide To find A2L-compatible tools, check out https://www.trutechtools.com/a2l-compatible-tools.html. Check out ESCO Group's website at https://escogroup.org. Check out their EPA 608 training at https://escogroup.org/training/epa608.aspx. We have also written an article about this topic, which you can read at https://hvacrschool.com/what-techs-need-to-know-about-a2l-refrigerants/ Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Eric Mele investigates several different issues with a restaurant's HVAC/R equipment, including an inefficient A/C compressor and a failed fan motor on a refrigerator. The readings indicate that the suction pressure is high, around 152 PSI, with an 80-degree return. The temperature split is only 10 degrees, and the unit is running too warm with low subcooling. When Eric pumps the charge down, he notices that his meter stalls out a bit. Then, he shuts off the blower and checks the suction line temperature. The suction line temperature rises past 91 degrees, meaning that hot gas is leaking back through the compressor. The data affirms Eric's suspicion of an inefficient compressor. Upon further inspection, Eric notices that the unit has an aftermarket fan motor, which may have damaged the compressor and contributed to the inefficiency that Eric is currently investigating. When running the unit without the blower fan, the suction pressure fails to drop as quickly as usual. So, the compressor is the primary issue, and replacement is necessary. Eric also inspects another small unit with filthy coils and a fan that won't spin. However, the compressor appears to pump normally. In this case, Eric replaces the fan motor and cleans the system. (As always, he makes sure the motor spins in the correct direction.) None of the bolts fit, however, meaning that Eric must use a set of customized screws. He doesn't put too many in all at once, as he wants to make sure the motor works and spins the right way first. Once Eric was sure that the fan motor worked as it should, he used a Dremel to customize the remaining screws and mount the motor correctly. He also redoes some wiring and sees if the unit can make temperature. He runs the unit in defrost and checks the amperage as the unit comes out of defrost. The relay appears to draw high amperage; upon further inspection, the relay appears to be working, but Eric still takes the safe route and replaces the start gear. The belt also has an issue; the belt is loose and runs counterclockwise. Eric replaces the belt, tightens it appropriately, and ensures that it spins in the proper direction. He props the motor up to get the correct belt tension, but the problem is bigger than that; the entire fixture will need replacement. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Eric Mele walks through the process of setting up the KE2 Evap-RE2. He goes shows how it connects to the wi-fi and First, Eric presses the “BACK” and right arrow buttons until the control shows that the wi-fi is ON. Then, he connects the control to his laptop, though a phone or tablet will also work. You will take your device and connect to “re2-xxxxx-xxx” under your list of internet connections (the “x” characters represent the number of the controller). You may also run a LAN cable from the laptop to the control in case the wireless connection does not work, or you may set up the control using its interface (though that is an extremely tedious process). Several components hook straight up to the control, including the suction pressure transducer and electronic valves. The control should also be able to read suction pressure, coil temperature, and return air temperatures. Accessory boards can also hold a few connections, such as to more electronic valves and sensors. Eric verifies that all of those boards and wires are in their correct spots. (The process includes tracing out wires.) At first, the system will only reference one room temperature and one pressure transducer, as you can see on Eric’s device. You must set your fan current and defrost current on the device. Then, you can go into important settings and adjust the parameters based on the equipment specs. You can also enable, adjust, or disable inputs on the device, and you can tell the system to use either main or auxiliary sensors. Even on medium-temp applications, defrost parameters still need to be set. Eric goes to the “Defrost” menu (accessible from the hamburger menu or the main screen) and leaves the setting at “demand” per the customer’s request. When setting the defrost current, Eric recommends setting the acceptable range to +/-10% of the amperage. (In his case, the fan had 24 amps, so he set the range to 2.5 amps in either direction.) Watch out for two-speed evaporator fans! With the KE2 contactor, we can’t use the low-speed fan, so we remove the fan wires so that the fans can run at high speed. Eric also comes across a spliced wire that plugs into Aux 1 Function. The spliced wire is the door switch for the freezer. When you change the function of the input by adding a new wire and components, you have to indicate that on your device. So, Eric sets the Aux 1 Function control to “Door Switch.” When the door opens or closes, you can hear the contactor adjusting to those changes, and the device’s interface for the control will reflect that. In cases where you’ve set the defrost to demand defrost, you may notice the unit going into defrost over and over again. A common cause of that issue is a pressure transducer that isn’t reading properly. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Eric Mele demonstrates how to replace a 3HP motor and install a control box with a motor starter. He also rewires the system and puts the low-voltage wires in a sealed junction box. Before Eric went to work on the motor, it had burned out, was replaced, and burned out again. He also notices insect nests in the panel, the contactor in the supply airstream, a missing keyway, and an oversized breaker, which are all less than ideal. The pulley also cannot spin and is in poor shape overall. Eric attempts to remove the pulley with a two-jaw puller, but the task proves difficult; the motor shaft doesn't spin at all. Since the pulley has suffered so much damage, Eric replaces it entirely. Eric disassembles the contactor, which has been warped from the motor burnout. That contactor tripped the 60-amp breaker. Eric wires the motor for the 208-230v application. The high-voltage wires go to the motor starter and feed into the top, and the wires go down into a new 20-amp breaker. All of the wires are #12 wires. Additionally, the motor starter has a high-voltage coil, and a relay pulls in the starter. If the overload relay were to change state, it would stop the motor. The wiring is configured so that the compressor will not run if the contactor is not pulled in; this is a common practice in commercial equipment . The high-voltage wiring joins with the low-voltage wiring in the junction box. Eric ties in the condenser to the thermostat (white), float switch (breaking red), 600v rated wire to starter enclosure (green or yellow), and common (blue) wires. He labels everything to keep track of all of the controls. When Eric runs the blower, he checks the amperage at the control box. He discovers that the white wire gives the cooling signal to the condenser, so he decides to switch it with the yellow wire at the box. He also draws a schematic, fixes any bent components, and seals up the conduit and all the holes he finds to prevent moisture from getting into any of the electrical components. Before walking away from the job, Eric also adjusts his relay and tests it to see if it stops the unit when it's supposed to. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Jim Fultz with Emerson discusses universal controls and how HVAC technicians can expect to use and interact with them. He specifically focuses on White-Rodgers aftermarket controls in heating equipment. Universal components work across all systems, such as modern thermostats; you can see thermostats on gas furnaces, heat pumps, straight-cool A/Cs, and more, and they'll all serve the same purpose. The "Universal" identifier merely indicates a part that works across several systems regardless of OEM. Universal controls aim to be easy for technicians to use when OEM parts are too expensive or impractical to order; customers also appreciate being given alternatives. On furnaces, a common burner component that can usually use a universal replacement is the gas valve. White-Rodgers aftermarket components can work for hot-surface or direct-spark ignition. In the blower compartment, we have the 24v transformers, which are critical components that allow universal components to work on systems. The "control circuits" that a 24v transformer connects with are the thermostat circuit, limit circuit, pressure switch circuit, gas valve, and ECM Speed Tap selection circuit. The integrated furnace control (IFC) is another critical component, as it fully controls all furnace operations; each control has specially designed functions for one or two-stage equipment, various blower motor types, direct-spark or hot-surface ignition, and OEM or universal options. Nowadays, universal kits typically have adapters to multiple furnaces, so they can work across several different manufacturers' models. You just have to verify the cross-reference of the voltage of the universal control to the IFC (such as via the WR Mobile app). After that, the installation instructions should tell you which harness you need for the conversion. Whereas the IFC is the heart of furnace controls, the defrost control is the heart of a heat pump system's controls. The defrost control manages the condensing fan motor, contactor, reversing valve, and coil temperature. It may also operate and monitor the high-pressure switch, low-pressure switch, outdoor air temperature, and backup heat. The defrost control may use one of two strategies: timed defrost or demand defrost. Of the two defrost strategies, demand defrost is favorable because it can result in longer equipment life, more cost savings ($200-400 annually), and offer better compression protection. White-Rodgers defrost controls can upgrade units from timed defrost to demand defrost with the Matrix LED by using thermostat and heat pump harnesses and thermistors. Contactors are components that require frequent replacement nowadays, which is ironic because they used to be the most durable part of the system. Contactors may come in the 1-pole, 1.5-pole, and 2-pole varieties. Most manufacturers tend to use 1.5-pole contactors nowadays. The SureSwitch universal part is a 1.5-pole contactor that can replace all three types. Contactors commonly have electrical arcing issues. Pitting and welding occur during arcing, which prevents contactors from opening or closing. Pitting and welding may also happen due to voltage drops or insect damage. The SureSwitch contacts are sealed, so it is an appealing replacement because bugs cannot access the contacts and cause welding or pitting. The SureSwitch also comes with protection against brownouts and short cycles; those benefits will lead to improved equipment longevity. The SureSwitch also comes with coil voltage options. The red cap on the spade can allow the SureSwitch to work with 120v, 208v, or 240v applications. Jim also discusses: Common White-Rodgers applications Furnace burner components Furnace blower assembly and blower motors Furnace operation sequence IFC pins Universal benefits Universal component usage for Carrier/ICP air handler boards Time defrost vs. demand defrost Setup and programming options with the 47D01U-843 State requirements for heat pumps Using auxiliary (backup) heat 47D01U-843 benefits on heat pump systems The anatomy of arc damage SureSwitch features White-Rodgers product warranties Future three-phase universal contactors SureSwitch compatibility with refrigeration systems Mounting the SureSwitch How WR Mobile works Visit the White-Rodgers website at www.whiterodgers.com. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Jim Fultz with Emerson discusses universal controls and how HVAC technicians can expect to use and interact with them. He specifically focuses on White-Rodgers aftermarket controls in heating equipment. Universal components work across all systems, such as modern thermostats; you can see thermostats on gas furnaces, heat pumps, straight-cool A/Cs, and more, and they'll all serve the same purpose. The "Universal" identifier merely indicates a part that works across several systems regardless of OEM. Universal controls aim to be easy for technicians to use when OEM parts are too expensive or impractical to order; customers also appreciate being given alternatives. On furnaces, a common burner component that can usually use a universal replacement is the gas valve. White-Rodgers aftermarket components can work for hot-surface or direct-spark ignition. In the blower compartment, we have the 24v transformers, which are critical components that allow universal components to work on systems. The "control circuits" that a 24v transformer connects with are the thermostat circuit, limit circuit, pressure switch circuit, gas valve, and ECM Speed Tap selection circuit. The integrated furnace control (IFC) is another critical component, as it fully controls all furnace operations; each control has specially designed functions for one or two-stage equipment, various blower motor types, direct-spark or hot-surface ignition, and OEM or universal options. Nowadays, universal kits typically have adapters to multiple furnaces, so they can work across several different manufacturers' models. You just have to verify the cross-reference of the voltage of the universal control to the IFC (such as via the WR Mobile app). After that, the installation instructions should tell you which harness you need for the conversion. Whereas the IFC is the heart of furnace controls, the defrost control is the heart of a heat pump system's controls. The defrost control manages the condensing fan motor, contactor, reversing valve, and coil temperature. It may also operate and monitor the high-pressure switch, low-pressure switch, outdoor air temperature, and backup heat. The defrost control may use one of two strategies: timed defrost or demand defrost. Of the two defrost strategies, demand defrost is favorable because it can result in longer equipment life, more cost savings ($200-400 annually), and offer better compression protection. White-Rodgers defrost controls can upgrade units from timed defrost to demand defrost with the Matrix LED by using thermostat and heat pump harnesses and thermistors. Contactors are components that require frequent replacement nowadays, which is ironic because they used to be the most durable part of the system. Contactors may come in the 1-pole, 1.5-pole, and 2-pole varieties. Most manufacturers tend to use 1.5-pole contactors nowadays. The SureSwitch universal part is a 1.5-pole contactor that can replace all three types. Contactors commonly have electrical arcing issues. Pitting and welding occur during arcing, which prevents contactors from opening or closing. Pitting and welding may also happen due to voltage drops or insect damage. The SureSwitch contacts are sealed, so it is an appealing replacement because bugs cannot access the contacts and cause welding or pitting. The SureSwitch also comes with protection against brownouts and short cycles; those benefits will lead to improved equipment longevity. The SureSwitch also comes with coil voltage options. The red cap on the spade can allow the SureSwitch to work with 120v, 208v, or 240v applications. Jim also discusses: Common White-Rodgers applications Furnace burner components Furnace blower assembly and blower motors Furnace operation sequence IFC pins Universal benefits Universal component usage for Carrier/ICP air handler boards Time defrost vs. demand defrost Setup and programming options with the 47D01U-843 State requirements for heat pumps Using auxiliary (backup) heat 47D01U-843 benefits on heat pump systems The anatomy of arc damage SureSwitch features White-Rodgers product warranties Future three-phase universal contactors SureSwitch compatibility with refrigeration systems Mounting the SureSwitch How WR Mobile works Visit the White-Rodgers website at www.whiterodgers.com. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bryan talks about parallel circuit resistance. He discusses what happens when you take multiple electrical circuits and run them in parallel. When you run equipment in parallel, a separate path goes to each load. The load is the part of an electrical circuit that does something. Examples include motor windings (inductive) and filaments in lightbulbs (resistive). When you run multiple loads in parallel with each other, you connect each side to the power supply. In a series circuit, the loads are connected to each other, not each to the power supply. The electrons must move through each load as they proceed to the final load. You can add up the resistances of each load to get your total circuit resistance. In a parallel circuit, the voltage is the same across all the loads. That’s why you can get 120v to the lightbulb in your bathroom and in your bedroom all the way across the house. For amperage, you add the amperage of each circuit to get the total circuit amperage. However, the resistance DECREASES for each load you add to the parallel circuit. If you connect a single lightbulb to a circuit, the total circuit resistance is just that of the bulb (and an insignificant amount from the conductors). When you add another bulb to the circuit, the resistance decreases; you can calculate the total circuit resistance by dividing each load’s resistance (R) into 1 (1/R). Then, you add those values together to get total resistance (Rt) and divide that sum into 1 (1/Rt). The idea is to get you to understand the relationship between resistance, voltage, and amperage in a parallel circuit. You have more current in a parallel circuit, so you will have lower resistance. The more parallel circuits you add, the more current you will draw; in turn, your total circuit resistance will be lower. In a parallel circuit, electricity does NOT take the path of least resistance; it takes all available paths. The amount of current is just proportional to the resistance. You can read our HVAC School article on Parallel Circuit Resistance at https://hvacrschool.com/parallel-circuit-resistance/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bryan explains how to install and adjust belts. Belt tensioning is a critical part of commercial HVAC work, though they’ve slowly been disappearing as blower motors and fan motors become more direct-drive. A common belt myth is that you need to tension a belt so that it has an inch of deflection. Many factors can affect deflection, including the pressure you apply to the belt, the belt’s length, and what the belt is made of. There are no hard, fast rules of thumb for working with belts. However, we recommend using the Browning app to help you if you’re unfamiliar with belts and typical procedures with them. If you’re working with an adjustable drive pulley (sheave), DO NOT adjust the pulley itself to set the belt tension. Instead, you have to adjust the foot mount on the motor to set the belt tension. Before you replace the belt, check the pulley condition; the problem could lie there, not with the belt. Replace the pulley if it is damaged. When you adjust the two halves of the pulley closer together, you can expect more airflow. When you adjust them to sit further apart, you decrease the airflow. So, you must measure airflow to set those halves correctly. We don’t typically adjust those in the field, but we have to adjust the motor base inward if we want to replace a belt. When the old belt comes off, we want it to be loose. Of course, we must also put the new belt on loosely and tension it appropriately once we finish the replacement. You’ll want to avoid overtightening the belt, so a tensioning tool will be especially effective here. A proper tensioning tool allows you to apply a set amount of force and then look at a fixed amount of deflection. Browning makes a tool specifically designed for this purpose. (Product link: https://www.regalbeloit.com/products/mechanical-power-transmission-components/belt-drives/belt-drive-accessories/belt-drive-accessory-belt-tension-checker-1302546) You should not set your belt tension based on blower amperage; the blower motor could run well below its peak conditions. Instead, you want the belt to be as tight as possible without slipping or squealing under peak-load conditions. Overall, if you need to do significant adjustments, you may as well replace the belt. Always inspect the whole system if there is slippage, too. Browning belt tensioning instructions: https://regalbeloitliterature.callmss.com/literature.php?_ga=2.262639756.1834621216.1630605224-836700809.1630605224#view_8082E Browning video on How to Check if your V-Belt is Properly Tensioned: https://www.youtube.com/watch?v=m2inwbm9Q6E&ab_channel=RegalBeloit Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Eric Mele shows us a condenser that he has adjusted. He also added buck-boost transformers in the “boost” configuration. The incoming power supply is low, so the boost configuration increases the voltage from primary to secondary. The condenser fans have been rewired. In the current configuration, the failure of one fan won’t take the other fans out. However, our main goal is to prevent fan failure altogether. We have moved the circuit board over to make room for the buck-boost transformers. Eric installed two transformers and drew out the schematic on the panel so that future technicians can understand how he wired those transformers. The left of the schematic represents the low-voltage incoming power, and the right side shows the high voltage. From line 1 to line 3, we only measure 201 volts on our incoming power. From line 1 to line 2, we measure 197 volts, and line 2 to line 3 measures 202 volts. However, with the help of the transformers, line 1 to line 2 boosts up to 222 volts. Line 2 to line 3 measures 217 volts with help from the transformer, and line 1 to line 3 measures 221. We also have a control transformer tied into the low-voltage side of the system, and we get 200 volts to that transformer. Anytime you make changes to the wiring of a condenser, keep the old wires with the system in case anything needs to be rewired. Create a schematic diagram as Eric did and make sure you provide all the important information that the next technician needs to know. Our overall goal is to improve motor longevity. Motors can be expensive, so we want to minimize preventable costs and equipment casualties as much as we can. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Eric Mele tours a motor room for Emerson direct expansion (DX) equipment with two medium-temperature racks with remote headers. DX systems use a typical compression refrigeration cycle to accomplish cooling. The remote headers for each rack are placed along the motor room walls, not within or immediately beside the racks. Each rack has multiple compressors that discharge compressed vapor into a single common discharge line. The discharge line leads to the oil separator, and then it leads to the heat reclaim or condenser. The oil separator has an oil line that leads to the oil reservoir. The reservoir stores oil until that oil needs to make its way back to the compressors. Then, the oil passes through an oil filter and heads to the compressor. Each compressor has an oil regulator with a sight glass to ensure proper oil feeding. Stemming from the discharge line on rack 5, there is a smaller line for hot gas defrost. However, the defrost isn’t used on that rack. In this particular system, the air conditioner’s heat reclaim is a reheat coil, which also helps with dehumidification. Then, another line leads back to the rack and forces the refrigerant through a check valve, which leads to the condenser. On the second rack (rack 4), half of the condenser has been eliminated, which we can see on the piping and when we go outside. From the condenser, you will find two liquid lines with check valves. In some cases, a rack will have a condenser split valve, but the rack in the video does not have one. The refrigerant in the liquid line goes to the receiver (with a liquid level indicator) and then the filter-drier. Once the refrigerant passes through the drier, it travels all the way to the remote header, where the liquid header is. The suction header is on that same remote header and may not have a suction drier. Each evaporator has an electronic EPR valve to throttle the suction pressure and maximize runtime. Those valves close during defrost. Then, the suction header extends all the way back to the rack and the compressors on it. The other rack has a defrost differential valve. That valve creates a pressure differential to establish the flow of hot gas through the defrost header (on the remote header) and up the liquid line. On this equipment, the compressor contactors are behind a panel on the rack itself, and each contactor has its own control breaker. The controller is also on a panel on the rack. You will find the relay board behind that controller The defrost board is behind a panel on one of the remote headers. The schematics are behind that same panel. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Commercial technician Eric Mele diagnoses improper dehumidification on a Seasons 4 system with reheat. He goes through the diagnostic process on the Seasons 4 RTU in the field. Eric starts by tracing the wiring so that he can understand exactly how the system is wired. He checks his control board to see where all the wires are hooked up and how they’re configured. While checking the system, he notices that a three-way valve is closed, so he opens it. He feels water moving through the hot water coil, but he needs to be sure that the flow rate is correct. When Eric finds the analog output for the modulating damper, he measures it with his voltmeter and reads 6.1 amps DC, which falls within the 1-10-volt throttling range. The choice to open the valve affected the dew point, and the hot water coil became warmer. Eric wonders if the system didn’t have enough water flow to retain the heat in the water until he opened the valve. He also notices that the “Compressor 1” switch has been set to “Module Reset,” which seems odd. We can verify if that is correct or incorrect by checking the manual. Compressor 1 also plays a role in dehumidification. Only two steps of cooling are on at the moment, too. The dew point comes back up, and the supply temperature is a bit high. However, the AHU status is in “Reclaim Cool Dehumidify.” When Eric attempts to change the Compressor 1 switch, it flips back to “Module Reset.” Eric checks out the discharge and notices that the hot water reclaim is using up all of his discharge gas. So, none of the discharge gas is going to the air handler! When Eric returns to the control boards, he notices that the dew point is nearly back down to normal, and the DC voltage on the valve continues to drop but is still in range. So, the valve is trying to open a little more. After reviewing the dew points over the past few days, Eric becomes more confident that the system is not getting enough hot water from the rack. The discharge gas going into the heat exchanger is extremely hot, but the pipe leading out of the heat exchanger is cool enough to touch for a long period of time without Eric burning his hand or feeling uncomfortable. When Eric returns to the control boards again, his voltmeter reads 2 VDC at the analog output, meaning that the valve is entirely open. All compressors are running, and we have a 5-degree temperature rise, which is optimal. So, it appears as though the issue was the closed three-way valve all along. The three-way valve is a bypass valve. In this video, it is near the return side, so it is a mixing valve. (A valve on the supply side is called a diverting valve.) When that bypass valve was closed before Eric came, the system got very little water flow from the return pipe, as the water wasn’t mixing with the supply water. So, the valve did not properly respond to a call for dehumidification because the coil never got warm enough. Since this application only has one coil, it must have a three-way valve. You can use some two-way valves on systems with multiple coils. When Eric goes back to check the discharge after fixing the problem, the pipe leading out of the heat exchanger is finally very warm to the touch. The shaft seal is leaking, but that is easy enough to repair without an extensive diagnostic process. When the coil is inactive, Eric’s voltmeter reads 10 VDC, which indicates that the valve is closed. However, dehumidification is active. It turns out that the dehumidification signal to the valve is flipped. Eric overrides the dehumidification to “inactive.” Eric comes back and discovers that once the space dew point is satisfied, the controls display the outdoor air dew point. That indicates that the system has a flexible combiner that shows a new relevant measurement when one is satisfied. (In our case, the space dew point was satisfied, so the controls show the outdoor air dew point afterward.) The drive was also not initially programmed for the correct application. Overall, Eric fixed the three-way valve (water flow to the hydronic loop), corrected the analog output setting to the valve, and communicated with Seasons 4 to configure the drive properly and confirm that the system was working properly. Learn about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Bryan explains how to detect line set leaks and do a line isolation test in 9 steps. If you’re struggling to find a leak in a split system’s line set, you may consider performing a line isolation test as a last resort. As we experience more and more copper corrosion and pinhole leaks in ductless line sets, thorough leak detection and line isolation tests will become even more valuable procedures. First, you’ll want to perform a thorough leak check on the system. You may check for leaks with a pressure test. If there is refrigerant in the system, you will want to check for leaks with a quality electronic leak detector, such as the Bacharach H-10 (https://www.trutechtools.com/Bacharach-H10-Pro-Univ) or Fieldpiece DR82 (https://www.trutechtools.com/fieldpiece-dr82-infrared-refrigerant-leak-detector.html). No matter which leak detector you choose, use it slowly and maintain it properly. You can run a heat pump in heat mode to increase pressure in the evaporator and make leak detection easier. Run the leak detector into the chase to check for leaks there. If you still can’t find a leak, then it may be time for a line isolation test. Before doing the line isolation test, you’ll pump down the system by closing both service valves at the condenser. Crack the suction valve open about two turns. Make sure the system runs in cooling mode, and watch for the gauge pressure to drop about 10 PSI. Remember, you want to pump down as best as you can to avoid dealing with the possible cross-contamination of recovery. Tighten the suction line and pull the disconnect once you’ve finished. Before you can install a service port on the liquid line side of the evaporator, you must isolate the evaporator. Then, you cut the copper line and pinch it off. If you install a Schrader core, you can pressurize the line set and the evaporator coil. When you do your pressure test on the lines and evaporator coil, you should use nitrogen in accordance with the low-side pressure test protocol. Watch over the system and note any pressure drops over at least an hour. (We recommend using Fieldpiece Job Link probes: https://www.fieldpiece.com/product-category/job-link-system/.) While the system is under pressure, go back into the condenser with a leak detector and check it once more. Once you find and fix the leak, it’s a good idea to identify the source of corrosion and develop measures to avoid letting the issue happen again. Then, you can release your nitrogen and begin closing up the system. Reattach the copper lines to the evaporator and change out your liquid line drier. After you’ve put everything back in order, perform one more pressure test. Use a bubble solution to check your braze joints, too. We recommend using Big Blu from Refrigeration Technologies (https://www.refrigtech.com/big-blu/). Once all of those have been taken care of, pull your vacuum below 500 microns to perform a decay test. Then, you can open the system for service by opening the suction side valve and then the liquid side valve. You would perform many of these final procedures on new installs as well. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In today's live stream, Eric Mele and Bryan talk about dehumidification and reheat on the residential and commercial sides of the HVAC industry. Recently, Eric diagnosed a commercial RTU that wasn't reaching the set dew point. In the hydronic system that Eric troubleshot, the analog output was flipped; it ran the valve for reheat in reverse. These hydronic systems use waste heat from the refrigeration rack to heat water in the system; that water then circulates to the unit in lieu of refrigerant circulation. Dew point is a critical element of psychrometrics from a moisture/condensation standpoint, especially in commercial spaces. Air that reaches the dew point temperature will begin to condensate on a nearby surface. Higher airflow can reduce condensation, and condensation may be a slow process, but it will happen after you reach the dew point. Reheat results in dehumidification, but it's not because we warm the air. Instead, the A/C runs longer without overshooting the setpoint. Longer runtimes improve dehumidification. Overcooling causes condensation, so we don't want to overshoot the setpoint. If you still need to drop the temperature of a space, then reheat probably won't be necessary. Some common reheat controls are of the modulating variety; these have a variable signal depending on DC voltage or milliamps. You can control fluid within the reheat coil or control the amount of air moving across the reheat coil, though these utilize different strategies; you use a damper to control the air or divert hot gas with a valve. We have two main dehumidification strategies. We can use mechanical cooling, which is when we use our A/C units or some sort of cold coil to dehumidify the air; in this strategy, the equipment cools the air below the dew point, removes moisture from it, and reheats the air. Another strategy is desiccant dehumidification, which treats the air by removing moisture with a desiccant. A desiccant is a medium that adsorbs moisture from the air. Your typical stand-alone dehumidifier will have an evaporator and condenser in a reheating cycle. The air leaving the dehumidifier is typically hotter than the air going in, so the dehumidifier increases the sensible heat load. That higher sensible heat load can have a negative impact on your existing HVAC equipment. However, oversized systems can actually benefit from a higher sensible load because the greater load will increase the equipment runtime and pull even more moisture out of the air. But overall, while proper equipment sizing is important for dehumidification, it can only do so much to help with longer runtimes and latent removal. If you discharge that high sensible heat from the dehumidifier into the return, you will likely derate your equipment's latent capacity. So, you'll be better off discharging the high-sensible dehumidified air into the supply duct, but you have to take static pressure and backdraft possibilities into account. The best ways to improve your air conditioner's dehumidification efficacy are to keep moisture from entering a space in the first place, have a longer runtime, and use supplementary dehumidification. Poor dehumidification can result in vents sweating and other moisture problems in the conditioned space. However, sweating may also occur on the ducts in the unconditioned space. If your ducts are sweating, you can either heat the ducts or decrease the dew point of the air in that unconditioned space. You can only control the air in those unconditioned spaces via encapsulation or ventilation. Humidity in the conditioned space can come from ventilation; the home may pull humid air in from the outdoors. Pulling air into a space can worsen the humidity problem if you pull the air in from an undesirable source. Sealing your home will help, as will using a ventilating dehumidification strategy that filters the fresh air. If you need to increase humidity, such as in a wine cellar, the best solution is to make sure you run a warmer evaporator coil. The cold coil is the key to dehumidification in compression-refrigeration systems. Evaporator pressure regulators (EPRs) and automatic expansion valves (AEVs) can help regulate the conditions of those evaporator coils. Eric and Bryan also discuss: Insulation/sealing Condensation and defrost on grocery equipment Building pressure in commercial settings Balancing pressure in residential spaces Reducing setpoint for over-dehumidification during favorable conditions Energy recovery ventilators (ERVs) Suction pressure changes, compression ratio, and system capacity Low vs. auto fan usage and dehumidification Duct leakage Ductless mini-splits and poor latent load removal Caveats of overcooling and airflow for dehumidification Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Ed Janowiak of ACCA gives a presentation about Manual S and what it means to have proper airflow. He gave this presentation at the second annual HVACR Training Symposium. You can learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/. While Manual J deals with residential load calculations, Manual S deals with residential equipment selection. The equipment’s goal should be to maintain 70 degrees in the winter and 75 degrees in the summer (with a 62-degree WB). These are not Manual J goals; they are goals of the entire residential design series (Manual J, Manual S, and Manual D). When consulting codes, remember that those are MINIMUM standards. However, some of these codes refer to Manual J and Manual S, including IECC. The sensible heat ratio (SHR) dictates the airflow you’ll need (CFM per ton). The location and equipment manufacturer can affect the SHR, but they do not determine the CFM per ton alone. You must perform a load calculation to separate sensible BTUs from latent BTUs. Then, you divide your sensible BTUs by total BTUs to yield a ratio. Your equipment performance data will determine blower performance. The manufacturer publishes these data sets, including heating performance data and expanded cooling performance data. (Expanded performance data can also tell you the WB, which is important in terms of meeting your design goals.) Follow that guidance for equipment selection (Manual S). You may have heard of the 400 CFM per ton rule of thumb, but it’s about as accurate as “beer-can cold.” It’s just a rule of thumb, and your calculations will help you get a more precise CFM target for equipment selection. It’s easier to determine capacity on a heating system, as all BTU/h are sensible. However, some cooling BTUs are latent, which complicates the capacity equation. Most manufacturers give you the total and sensible BTU/h, so you may have to do some math to determine the latent BTU/h for your SHR. Sensible heat ratio (SHR) tells us how many BTU/h are sensible out of the total BTU/h. For example, if you have 10,000 BTU/h with an SHR of 0.75, that means that 7,500 BTU/h are sensible and 2,500 are latent. When your SHR is higher, your capacity increases. Both the system and the house have a sensible heat ratio. When determining the CFM per ton with SHR, you can use your temperature difference (TD) in that equation. Manual S has a chart that tells you the TD for a given SHR. In that equation, you divide your sensible BTU/h by the product of 1.1 and your TD. You may get a number that’s far higher than 400 CFM per ton! Once you figure out your CFM, you can size your equipment based on airflow, capacity, and oversizing guidelines. Remove any equipment that is short on capacity from consideration. Manual S has 3 “N” sections, which refer to standards. N1 deals with definitions and general requirements, N2 deals with sizing limits, and N3 deals with OEM verification. N1 emphasizes the importance of using OEM performance data. Do NOT use the AHRI equipment performance data for sizing. While AHRI’s figures are good for getting a general idea, no data can compare to the manufacturer’s expanded performance data when it comes to accuracy. One of the most important tables in Manual S is Table N2-1 in section N2-5. It tells you how to select air conditioners for single-speed, two-speed, and variable-speed equipment. The table also gives you the minimum and maximum sizing ranges for air-to-air systems as a ratio, typically with a 0.9 minimum (90%) to 1.15-1.3 (115-130%). The same table for heat pumps is in section N2-6 (Table N2-2). When adding a dehumidifier, keep in mind that the sizing value is based on 85% of the latent cooling load. When making conversions to pints per hour, you take the latent BTU/h and divide it by 1,054. Overall, you must remember that Manual S says to meet the sensible and latent heat gains, but don’t exceed the total gain by 15% (single speed), 20% (two speed), or 30% (variable speed). On the heating side, you need to be able to counter the sensible losses in the heat. If a heating system cannot put out enough BTU/h to exceed those losses, you may need to add another source of supplemental heat and recalculate the BTU/h output to see if it exceeds the losses. If the BTU/h in sensible gain exceeds the losses, then the system will run satisfactorily for most of the winter. To find the heating load CFM, you take the furnace sensible output (BTU/h) and divide it by the product of 1.1 and the temperature rise (instead of TD in cooling systems). Ed also covers: Design software programs Interpolation Default TD values for CFM approximations Sizing for budget systems House SHR and leaky homes Sensible losses in the winter Modern furnace sizing Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this class, Bryan teaches the Kalos techs about long-line applications, accessories, and allowable line lengths. Many techs don’t fully understand the challenges of long lines. So, Bryan covers a wide range of issues and practices with long lines. You can find the long-line piping guide we’ve used at https://carriercca.com/pdf/products_pdf/24ABB3_data.pdf. Long lines can cause refrigerant migration. Long lines simply move more refrigerant, making migration much more likely. On top of that, a pressure drop is possible throughout longer suction lines. When you have a lot of refrigerant inside the suction line when a unit is off, it will often migrate to the condensing unit. (In a few specific cases, liquid refrigerant may migrate to the evaporator. Your unit is at risk of a flooded start when that occurs.) We also shouldn’t bury suction lines for long distances to reduce the risk of a flooded start. The ground is typically colder than the air, so the refrigerant is more likely to condense in the suction line if it is underground in a cold place. When the system is off, you ideally want liquid refrigerant to be in the liquid line or condenser coil. Anywhere from the discharge line to the metering device is in the “safe” zone for liquid refrigerant. So, when adding liquid refrigerant to a system, you will want to add it to the liquid line so that it can vaporize in the evaporator before making it to the compressor. We NEVER want liquid in the compressor, and we only want vapor to be in the compressor while the system is running. Straight-cool long-line A/C systems require TXVs if the line’s total length is over 50 feet. If the outside unit is above or below the indoor unit, that system will require a TXV if the line length exceeds 20 feet. TXVs are required in long-line applications because they have hard shutoff (HSO) or non-bleed valves that help prevent refrigerant migration. A long-line A/C system may also require long-line accessories. These requirements depend on the liquid line diameter, the presence of a TXV, and where the outdoor unit is located in relation to the indoor unit (above, below, or level). The range for minimum lengths can be between 35-175 feet, depending on each of those factors. (Most of the time, we use ⅜” liquid lines with a TXV, so the minimum is usually 80 feet.) Heat pumps with a ⅜” liquid line diameter and TXV will need long-line accessories if the lines exceed 80 feet in length (or if the vertical difference between the indoor and outdoor units exceeds 20 feet). Pipe fittings add equivalent length, so be sure to take those into account when you measure line lengths to determine if you need long-line accessories or not. Your allowable line lengths will be significantly greater when your condenser is above your air handler. When your condensing unit is higher, the refrigerant going to the air handler will maintain pressure more easily as it moves downhill towards the metering device. The static regain keeps the pressure drop from getting too strong. In the case of our Carrier heat pump, we have level indoor and outdoor units situated 100 feet apart. We have a ⅜” liquid line with a TXV, so we will need a long line because the distance between the indoor and outdoor unit will exceed 80 feet in length. As a heat pump, the unit will need a standard accumulator. Based on our accessories guide, we need a compressor start assist capacitor and relay (hard start kit), crankcase heater, and hard shutoff TXV. However, we also need a liquid line solenoid valve (LLSV). These LLSVs are NOT for pump-down applications; this LLSV shuts down the liquid line when the system shuts off. The hard start kit helps start up the compressor. The capacitance needs to be properly matched to avoid putting too much current on the start winding, so it’s a good idea to use the manufacturer’s hard start kit, not a universal one. When it comes to installation, we start off by installing the bellyband crankcase heater. The schematics can tell you how the crankcase heater attaches to the wiring. Remember, we only want the crankcase heater to energize when the unit is OFF. When we power up the condenser ONLY, we no longer read voltage to the crankcase heater. When we shut the unit off again, our meter begins to read voltage again. The next step is to install the hard start kit. We can test it by measuring our start amps with it in and without it in. We install the liquid line solenoid on the liquid line. It is a normally closed valve that opens when energized. It should be installed two feet from the condenser, and the arrow on the valve must point towards the outdoor unit. We also discuss: Pump-down or pump-off systems Potential relays Capacitor windings and startup amperage Wiring diagrams Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Today's live stream continues exploring the installation mindset. Duct experts Neil Comparetto and Michael Housh join Bryan to discuss ductwork, venting, and commissioning as they relate to the HVAC installation process. Many problems that occur during installations stem from poor duct design. Ductwork requires a lot more thought and planning than just using ACCA Manual D. Duct sizing is important, and HVAC systems often lose efficiency to takeoffs and return drops that are too small; Michael and Neil like to make the ductwork as large as possible to improve the equipment operation and use large filters effectively. Some equipment coils also have more pressure drops than others, and the ductwork needs to be able to deal with that. Know the performance of your fittings and what their equivalent lengths are. When you use filters, you want to make sure you maximize your surface area for the best filtration. The pleats of filters increase the surface area and effectiveness of each individual filter. Creating plenty of filter grilles and returns for your filters allows you to increase filtration without creating too large of a pressure drop. (Remember to use filters with high-quality media, and don't be afraid to diversify your filter selection if the ductwork has unique needs!) Oversized units may present issues with the ductwork. Whenever possible, look for opportunities to downsize the HVAC equipment during a changeout or retrofit. Turning vanes can confuse some technicians. These are usually more beneficial in supplies than returns, and they shouldn't present an issue if the ductwork is large enough in the first place. When installed correctly, these turning vanes can help even out turbulence and are great in cases where you have space constraints. When configuring elbows without turning vanes in the ductwork, make sure that the throat (inside) is large enough and that you have enough space for them. When it comes to metal duct fabrication, you need to think about getting the ductwork off the shelf as quickly as possible. Retrofits can be tricky and may require some custom adjustments to the ductwork. Modifying fittings can take more time than creating your own transitions. You'll also want to pay attention to the size of your air handler; larger air handlers can leave you without enough room to make a good supply transition. You'll also want to think about the ductwork's relationship to the structure. Neil recommends decoupling the ductwork from the structure as much as possible, such as through canvases. Cross-breaking is not as important as one might think, but you can still do it if you think the sheet metal might not be rigid enough. Flex duct provides a unique set of benefits and challenges. Flex ducts reduce noise, are well-insulated, and are leak-free. However, they can lead to poorer airflow if installed incorrectly. Keep flex ducts straight and tight, and you'll have no problem. When burying ductwork is a bad idea, strapping and routing are the processes that support the ductwork. Codes will give you a guide when it comes to the spacing between supports. Wider straps provide more support, especially if you can use a "saddle" material underneath. Leak prevention is critical in sheet metal duct systems. The best approach to solving duct leakage issues is methodical, not reactionary. You'll get the best results by approaching a job with the mindset of minimizing leaks from the beginning; use mastic on your elbows and do as much prep work ahead of time as possible. You only need to worry about venting when you use gas appliances, not heat pumps. Venting can go wrong when people size the flue incorrectly or use the wrong pitch on condensing appliances. However, most issues can be avoided by simply reading the manufacturer's literature. Pay attention to your terminations; avoid areas where terminations can be covered by snow. You should also check for signs of backdrafting, which is a dangerous condition. Commissioning is the time to set airflow correctly. The more measuring and benchmarking you do, the more likely you will catch something that could cause problems later. Static mapping is a great commissioning practice. Of course, you'll also want to check the refrigerant charges or combustion analysis before walking away from a newly installed system. Even though we highly recommend reading manuals and using all your resources during commissioning, your best tool will be good old common sense. We also discuss: Duct design modeling software Balancing dampers and design strategies Strategies for sealing fittings Drilling register grilles into place Addressing leak points at the boot Using a Ductulator or duct slider Using rules of thumb Gas piping Orphaned water heaters Using manuals Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Ed Janowiak of ACCA gives a presentation about fan and duct design, system testing, and Manual D at the second annual HVACR Training Symposium. Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/. Ed has over 35 years of HVACR experience, both in the field and through teaching. He has lived and done business in New Jersey, which has a variable climate, and he has experienced a wide range of temperatures. When designing ductwork, we obviously want our static pressure to be close to our calculations. However, lower static pressure is usually more desirable than higher static pressure. When static pressures exceed our expectations, we have to start removing elements of our design. The real key to good duct design is managing the occupant’s expectations. Understand what the client wants, but you must be up-front with what they can and cannot expect from their HVAC system. Manual D requires that you pick a fan and design the ductwork around the fan. Ducts must accommodate fan pressure. (Manual Q is the opposite; you choose the fan based on the duct resistance.) Manual D’s goal is to calculate the critical path, which is the longest circulation path in the system. It’s also a good idea to comply with local codes, but it is not responsible for a design’s predictability. To design a duct system, we also need to know how much BTUH (BTUs per hour) and CFM (cubic feet per minute) need to be delivered. We can get these figures by finding the BTU gain and loss (Manual J), and we can use Manual S to calculate our target airflow. Take the SHR (sensible heat ratio) into account, and you use all of that data to find your capacity. We should refer to the friction rate worksheet to develop a good duct design. You initially take your external static pressure and CFM readings. Then, you discover and note the component pressure drops. You also take available static pressure and total effective length into account. In the end, you will figure out your friction rate. The purpose of that worksheet is to determine the friction rate based on the duct system’s critical path. We use manometers to take static pressure measurements. Static pressure is NOT velocity; it is the measure of pressure against the walls of the duct. You can use static pressure as an airflow indicator. Several components can contribute to pressure losses in the critical path, including heat exchangers, UV lights, grilles, and dampers. However, the filter is the most notorious source of pressure drops. When sizing a filter, you need to know CFM, velocity, and area. The system must have enough pressure to overcome those drops in the system. Once you have calculated your external static pressure and losses, you can subtract those losses from your external static pressure to yield your available static pressure. You determine your total effective length by adding the supply and return-side total effective lengths together (including trunks, runouts, and group fittings of each one’s critical path). Then, to get the friction rate, you multiply your available static pressure by 100 and divide that product by the total effective length. (You should also be able to find that value on a chart on the friction rate worksheet.) Humans feel comfortable when they don’t notice their surroundings. So, excessive fan noise can be an unexpected source of discomfort for occupants. Watch your air velocity to avoid creating that humming sound with the fan. Don’t start off at high speed! Manual D gives us maximum air velocity guidelines to avoid comfort issues. Manual T also covers terminal velocity and grille selection, which heavily contributes to comfort. (A grille should be located in a sensible location and should have the proper throw. Grille size will determine the distribution box size.) You must determine your heating and cooling factors to begin working on your duct design worksheet. The heating factor is the blower CFM divided by your Manual J heat loss; your cooling factor is the blower CFM divided by your Manual J heat gain. When you use effective length charts, you must keep in mind that those effective lengths will only contribute to duct behavior predictably under a certain set of conditions. If you’re running at a slower fan velocity the friction rate will change, and you will need to do some more calculations. As friction goes up, effective length goes down. Our external static pressures may end up higher than we anticipated due to excess length (with flex duct). Ed also discusses: Alternative ways to measure static pressure Height-to-width ratio of ducts Design software pitfalls Return drop sizing Sizing for flex duct systems Round registers Grille air velocity and sizing Filter sizing Standard test airflow rates for MERV ratings Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this class, Bryan teaches the Kalos techs about breakers, wires, fuses, and overloads. The practices associated with these components can be a bit controversial in the HVAC industry, so we look at these through the lens of NFPA 70 (National Electrical Code/NEC). The wire sizing guide can be found in NEC 310.15 Table B-16, and NEC 440 is just for air conditioning. Most of our disagreements with electricians come from the separation of these two sections of the code, as electricians may not pay attention to NEC 440. (We also can’t agree on whether the circuit breaker’s main purpose is to protect the conductor at all costs or not.) A circuit breaker allows you to close a circuit manually; it is resettable. A circuit breaker has three settings: on, tripped, and off. A breaker that is ON will have its lever at the very top. An OFF breaker will have its lever at the very bottom. A tripped breaker will have its lever in the middle, so you can tell the difference between an off breaker and a tripped breaker. A breaker may trip due to excess current in the case of a short. If the current is only slightly over the breaker’s rating, the breaker may take a long time to trip. Arc fault breakers can get quite hot, but their high temperature doesn’t mean that they’re malfunctioning. Fuses come in many varieties, but each one has a current rating (and usually a voltage rating). Amperage will blow a fuse, but excess voltage could potentially cause arcing. Some fuses will blow slowly, and others will blow quickly, but the amount of overcurrent also dictates how quickly a fuse will blow. Fuses must be able to withstand a motor’s higher current upon startup, so we typically prefer slow-blow fuses for those. Fast-blow fuses need to protect electronics. Overload means that you’ve placed too much load on something. So, an overload is a device that breaks a circuit when there is too much load. When a motor’s physical resistance increases, its electrical resistance decreases. The electrical resistance decreases because the motor doesn’t spin as quickly and produces less back EMF. Your compressor can overload after coming out of defrost due to high suction pressure. The refrigerant is very dense in the suction line, so the compressor current must increase to deal with the load. A ground fault is an important electrical term; it is the momentary connection between a current and ground. A ground fault is similar to a short, and you can prevent a ground fault with a GFCI (ground fault circuit interrupter). Condensers will soon need GFCIs according to code. Overcurrent protection prevents excessive current; these components typically guard against instantaneous spikes of current. A circuit breaker is an example of overcurrent protection. Overload protection protects a system against a running overcurrent that causes overheating; these components typically protect from electrical problems and other thermal overload issues. A conductor is basically a wire. When sizing a conductor, we must consider circuit amperage, ambient temperature, insulation temperature rating, box/conduit fill, and voltage drop. The voltage drop must merely be acceptable; the NEC doesn’t require specific voltage drop parameters for sizing, for the most part. (Conductor length affects voltage drop, and you want to measure voltage under load.) Luckily, many manufacturers make it easy to access the data you need for proper conductor sizing on their products. Information on conductor temperature ratings can be found in NEC Table 310.104(A). (Be sure to check if you’re using copper, aluminum, or copper-plated aluminum.) We often use the left column on that table. Tightened connectors also have torque ratings that you must account for, not just ambient temperature. Also, make sure your termination points can accept the wires you plan to use. You can’t connect Romex to an outdoor coil because it would operate under damp conditions, which is a code violation. The insulation rating is just as important as sizing. Insulation doesn’t affect voltage drop, but more insulation will help prevent overheating. Voltage drop also does NOT indicate a hot circuit. Starting current is when the voltage is first applied to the windings, so there is no back EMF; starting current is always HIGH at first. Running current is the current level when the motor is up to speed (and back EMF is in play, providing resistance). Locked rotor amps (LRA) indicate the current that a motor will draw if the motor stays locked (5-6x running amps). Remember, mechanical problems often cause electrical problems. Make sure you give your connections good metal-to-metal contact. Also, only check connections with thermal imaging when the system is under load. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this class, Bryan teaches the Kalos techs about airflow and how it impacts system performance. He explains the factors that affect airflow and how those contribute to the overall state of an HVAC system. We use training equipment and MeasureQuick to demonstrate these concepts. On a typical no-cooling call, many techs start with a visual inspection to look for restrictions. These techs will likely check the cleanliness of the filter, blower wheel, and evaporator coil inlet. Some techs also check the return grille, as it may be dirty or have an extra filter. Frozen evaporator coils are also a symptom of poor airflow (frozen evaporator coils also cause even worse airflow). On the auditory side of inspection, listening for abnormal motor sounds can clue you in on the static pressure, especially when high static pressure affects ECM motors. Alternatively, strange motor noises can tell you about the motor or blower wheel’s health. For example, PSC motors won’t ramp up under high static pressure; abnormal noises indicate bearing wear or a loose hub on the blower wheel. Customers may cause low airflow in their HVAC systems. For example, customers may close supply air vents to force more air into another room. (To force more air into rooms effectively, an HVAC contractor can cut a duct board so that it flexes and has a small hole, and then they’d insert it into the supply duct to act as a secondary damper. However, this practice may increase static pressure along the way and negatively affect airflow.) Customers may also move furniture in front of the return and obstruct airflow. Pet hair can also plug returns and filters. Other causes of poor airflow include collapsed or disconnected ducts. Insulation in the unit can also suck up against the blower. (Don’t pull panels off while the unit is running to avoid letting the insulation cause a restriction.) Water in the return can also cause airflow restrictions, especially in flex duct systems. Fire dampers may cause poor airflow in commercial applications. Slipping belts or poorly adjusted sheaves can also contribute to poor airflow. Before taking any measurements, make sure your gauges have been zeroed out and calibrated against each other. When you have poor airflow, your typical measurements will be either normal or low. You can expect your superheat to be normal to low. Your suction pressure, head pressure, and delta T will also be low. Static pressure is NOT a measure of airflow, but it can tell you about the airflow; you can have poor airflow if the static pressure is good, but the motor may not be producing enough airflow. However, the ULTIMATE indicator of low airflow is a low suction line temperature; any suction line temperature lower than 50 degrees (F) with normal indoor temperature is a likely indication of low airflow. Some tools that measure airflow include TrueFlow grids, vane anemometers, and hot wire anemometers. However, these are advanced tools, and each one has its limitations. So, the best way to spot a system airflow problem is to perform those inspections with your senses and take your standard measurements. As air moves over the evaporator coil, it comes into contact with the fins. Heat moves from the air to those fins, as heat moves from warm air to the colder fins. That heat transfer is critical for moving heat from a space, and fins help the evaporator maintain pressure. When you have low airflow, the compressor amp draw will drop. The reduced pressure indicates that the refrigerant has less mass. The compressor does less work, but it doesn’t get cooled off as easily, and flooding is also possible. In our class, we used the training equipment to simulate various low-airflow conditions. We also used the MeasureQuick app to profile the equipment, determine our ideal measurement ranges, and display our data. The MeasureQuick app determined that our superheat was hunting and that we were overfeeding our evaporator. After troubleshooting the unit, we reduced our supply airflow. Our suction line pressure sharply decreased. We then jammed cardboard in the return duct, and our TESP sharply increased. Overall, our suction line temperature decreased sharply, TESP increased sharply, and subcooling increased slightly. MeasureQuick determined that we were running 249 CFM per ton, which indicates very low airflow. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this class, Bryan teaches the Kalos techs how to diagnose the low-voltage electrical components of a heat pump and a straight-cool system. This video is the second part of our series on low-voltage electrical diagnosis in residential HVAC units. Techs often make mistakes when stripping wires. When you strip a wire by wringing it with your stripper’s jaws, you can nick the wiring. Generally, you’ll want to make a small split in the casing and gently use your wire stripper to pull back on a conductor you won’t use. That way, the casing will strip away quite easily, and you won’t risk nicking any of the important wires. When routing wires into a heat pump, make sure that you keep those wires away from the air handler. The indoor coil can become quite hot in heat mode and damage the wires. You will also want to avoid vibrations and sharp edges that could damage the wire. You can ohm out your wires to look for open areas in a circuit that’s not energizing. Before you attach any wires to the HVAC system, you can check for breaks in the path with an ohmmeter. You do that by connecting all of your conductors together and putting your meter leads on two different conductors at the same time. If you have an “open” reading (infinite ohms), you have an incomplete path. You DON’T do this test if you have a blowing fuse. Wires that are exposed to the sun or excess heat can lose their colors. You can figure out those colors if you connect them to ground while each color is connected to the system. When we begin diagnosing Bryan’s heat pump system, Aaron first checks to see if the blower is running (it is). He then checks if the compressor fan runs (it does). Aaron also ensures that the thermostat is on and the refrigerant is flowing through. However, the system is supposed to be in heat mode but is cooling. The reversing valve was being energized when it wasn’t supposed to be. Instead of checking behind the thermostat’s face with a meter, the team pulled the battery out to make sure there’s no 24v power. The system appears to have a popped fuse. After the team takes their readings, they use the Short Pro to confirm if the fuse blew. Sure enough, a 3-amp fuse blew due to a short. Bryan’s team looks for the short using Eric’s method: using an ohmmeter on a de-energized circuit. They look for an ohm reading near 0 on the wire nuts, and they determine that the short is in the G conductor. When the team energizes the system without the G conductor, the system does NOT run as normal due to the thermostat’s overload protector. Then, the team disconnects the wires from each other and decides to connect each one to the 24v power supply individually. After turning the system on to test it, the team discovers that the orange wire (reversing valve solenoid) is not energized. Since the orange wire is connected to the contactor coil, the team decides to check for an open circuit. There is an open circuit between the thermostat wire leading from the air handler to the condenser. The team checks the ohms from the orange wire to another working wire (yellow) for confirmation. When we begin diagnosing Bert’s straight-cool system, the thermostat is blank. The team quickly notices that there is an open switch that has turned the power off. However, the thermostat remains blank after closing the switch. The team decides to check the transformer where it connects to the circuit board. They set their multimeter to pick up voltage between hot and common. The team discovers that no voltage is coming out of the transformer, and they trace the problem further to the power supply (L1). No power has been going to the board OR the transformer. The team checks for loose connections; there are no loose connections, but some of the switches are off. Bert’s team checks the incoming power, and the main breaker is off. Once power is restored, the condenser doesn’t come on. It looks like the thermostat’s time delay keeps repeating, so the team works to bypass the thermostat by putting a wire nut on R, G, and Y. The blower doesn’t work, and the team notices an error code. The blackened fuse indicates that a short occurred and blew the fuse. After ohming out the fuse, the team can confirm that the equipment has blown a fuse. The Short Pro indicates that the short occurred on Y. When Bert’s team checks the yellow wire at the condenser, the meter doesn’t indicate that there’s a path on the yellow wire. There may be an issue with the contactor coil, so the team checks the ohms on the contactor (0.6 ohms). After checking the ohm reading against a brand new contactor (12 ohms), the team determines that the resistance is extremely low; too much current went through the system and led to the fuse blowing and the time delay resetting. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In today's live stream, we discuss strategies for dealing with difficult bosses and co-workers in HVAC/R work. We won't get along with everyone in our workplaces, but we can figure out how to communicate effectively without letting them wear us down. If you work with negative people, let them be miserable by themselves. The best way to deal with them is to ignore them while you're working. Instead of focusing on shared complaining, try to focus on the common goal of getting work done. Moreover, you can avoid contributing to a negative environment by leaving work drama at work and home difficulties at home. Anger issues are common in our trade. You can deal with others' anger issues by acknowledging the inappropriate behavior and understanding that you can't communicate productively when tempers are high. When you have to address the behavior, don't attack their character but be direct about how that person's anger affects your work relationship. In extreme cases, give them space and walk away. If YOU are an angry person at work, try to address the root cause of the anger and work through it. Put structures in place that prevent you from lashing out at other people. Careless people are also everywhere in our trade. You can deal with inexperienced people by remembering how you were when you were at their career stage; you can empathize with them and give them the appropriate space or tools to develop. If the carelessness comes from distractions, such as their cell phone, try to address the distraction and reroute the careless person's attention to the job's mission. Micromanager leaders who tend to get over-involved in projects can annoy their teams at best or stunt their development at worst. These leaders can improve their relationships with their team by setting clear objectives and giving their techs the room to develop. Sarcasm, rudeness, and condescension are all undesirable traits in the workplace. If you work with someone who is too sarcastic or condescending for you, calmly set that boundary with them that they can agree to. For example, you'll likely want to draw a clear line regarding racist and sexist jokes. If you are sarcastic, rude, or condescending, try to focus on communicating in a way that accomplishes the mission. Cliques and tribes will form in any workplace. However, they can be annoying and difficult to work with. Your goal is to develop as many allies and as few enemies as possible in the workplace. So, being kind whenever possible is the best way to avoid clique culture. Nepotism is also a sad reality in some organizations, especially in a few family-owned ones. The best way to address it is to talk to a leader about it; be straightforward and express your desire to work for a merit-based organization. You don't want to be a part of a business that shows favoritism towards family members anyway. Many of the worst leaders refuse to invest in training and education. The best way to deal with these leaders is to know what you need to learn. Then, you can communicate your needs with your leaders. A leader who ignores that type of request is probably not worth working for anyway. Egomaniacs are a particularly annoying variety of co-workers or bosses. The best way to deal with egotistical co-workers is to talk to them with a couple of other people to provide some perspective. It is much harder to reform leaders' big egos; you must decide if that leader is worth working for or not. Exaggeration and lying are also inappropriate at work. Those habits lead to poor training and misconceptions. When dealing with liars and exaggerators, feel free to ignore them or question their stories. Dishonesty with customers is a serious flaw in the workplace. If you have dishonest co-workers, kindly try to convince them to do better. If your workplace is shady, the only solution is to work somewhere else. Unwillingness to learn is also difficult to deal with. If someone has the potential to learn, help them learn how to "learn" by using similes and metaphors to build their mental models. Lazy co-workers and those who perform poor work also fall under this category. Again, try to help those co-workers learn to become comfortable with good, hard work by setting standards. Overreactors can also cause discord in the workplace. Many overreactors care a lot about their work, so it isn't a completely horrible trait. The best thing you can do is deescalate the overreactor's emotions respectfully and show that you care about their concerns. If you're the overreactor, take a step back and observe the situation. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In this class, Bryan teaches the Kalos techs about low-voltage electrical diagnosis in the HVAC field. Low-voltage electrical operations confuse quite a few technicians, so Bryan covers basic circuits and clears up some misconceptions about the terminology we use. Circuit boards seem to trip up a lot of techs. Unfortunately, every circuit board has a different configuration, so it is difficult to teach the topic from a general angle. Instead, we can isolate the circuits and functions of a circuit board. Then, we can explain how those fit into the basics of electronic applications. Techs will get a solid understanding of a system’s electronics by learning about the sequence of operation. Each system has specific terminal designations, and the tech should know what all of those are for. For example, the Y circuit on a split-cooling system energizes a contactor and is associated with the compressor and cooling. On a two-stage residential split-cooling system, both Y1 and Y2 must be energized for the system to function at full capacity. However, the Y circuit is not necessarily associated with cooling on a heat pump system. So, saying that the “cooling call” is on the Y circuit is NOT accurate for all systems. During a cooling call on a heat pump system, you must energize O (usually orange) to enter cooling mode. Consequently, memorizing circuit boards and electronic applications can be difficult for technicians who rely on memorization and don’t have a solid grasp of theory. Techs can, however, memorize the four basic components of the refrigeration cycle (evaporator, compressor, condenser, metering device) and the basic circuits on the low-voltage side for heat pumps and straight-cool systems. Even though we say that many electrical failures are “shorts,” not many people know the true meaning of the term. A short happens when a circuit takes an unintended path. To diagnose a short, you have to know the intended path and see where the circuit tried to take a shortcut and bypass the load. When the current bypasses the load, it experiences little to no resistance. Blown fuses and tripped breakers on the transformer indicate shorts. A fuse blows when too many electrons flow through it (the current is too high). Another type of short that doesn’t involve a blown fuse. When wires rub out, the current may bypass the switch but not the load. We can refer to these as “switch-leg shorts.” We also tend to misuse or overuse the word “common.” “Common” merely refers to a place where you connect things together. For example, the C terminal on a capacitor is the common point between two capacitors. On your compressor, the common terminal is the common point between the two windings (run and start). On a low-voltage circuit, common is the opposite of the hot side (24v); common if often connected to ground. “Open” refers to a break in a path that may be designed or undesigned. For example, an open switch is designed; when a switch is opened, the electron flow stops. So, electricity stops flowing through the circuit, and the system components on the circuit shut off. When using a multimeter, it is a good idea to set your meter on the ohm scale first. Voltage goes to the leads and will start looking for a path, so you can test your leads by putting them together. When using the ohm scale, make sure you differentiate between no ohms and infinite ohms. You can also test your multimeter by setting it to the volt scale and testing the leads on a known power source, such as an outlet. As always, wear safety glasses when working on live circuits. Check out TY's video on Analogies for Magnetism here: https://www.youtube.com/watch?v=OWYAqDOu4gM&t=300s Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

We illustrate how to recover refrigerant from a system with a working compressor. The system in this video is being decommissioned, so it is acceptable to recover refrigerant while a unit is running if it will no longer be in operation after the recovery. We use the Fieldpiece MR-45 digital recovery machine instead of a manifold to recover the refrigerant (you can find that machine at https://www.trutechtools.com/Fieldpiece-MR45-Digital-Recovery-Machine). It is a good idea to recover for a bit before turning the recovery machine on. On the machine, you will see the input and tank pressures start to equalize. Some units, like the Fieldpiece MR45, can be throttled. When the machine starts, the tank pressure will rise a bit and pull the refrigerant in relatively quickly. Remember to weigh the charge in the tank every time you recover. Keeping the tank on a scale can also let you see the slowdowns in recovery. However, even if you don’t use a scale, you can still tell when your recovery is almost finished; the inlet pressure will drop heavily when the refrigerant has been almost completely recovered. Even though the unit is running, the best practices remain the same: use large hoses and core removal tools for fast evacuations. However, another best practice is to place something on the condenser unit, such as a toolbox, to raise the head pressure during recovery and increase the pressure differential that allows the refrigerant to flow out. As an optional practice, you can take a pinch-off tool and crank down on the liquid line to raise the head pressure even more. This procedure will be crucial as we decommission more R-410A units. You will notice an uptick in R-410A systems being decommissioned as R-22 slowly disappears. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

In today's live stream, Bryan and Jesse discuss money in the HVAC business world. Jesse is the VP of Mechanical Operations at Kalos, and he guides and supports the Kalos team with a growth-oriented mindset. Kalos was founded in 2005 by tradesmen. The money and administrative sides of business did not come naturally to the founders, so Bryan and Jesse discuss how Kalos has evolved and how the company leaders think about money today. The first step for any successful business is to provide customers/clients with a product or service of value. However, there must be a balance between providing something of value to customers and providing excellent customer service. When starting an HVAC business, one of the biggest mistakes is making money the top priority. Although money is important, it can only come in when a business establishes the value of its services and communicates its value to its customers. There is no hard line for fair pricing, so the communication between the contractor and the customer needs to negotiate and establish expectations for the work performed and its price tag. That same mistake applies to employees who want raises or promotions; those employees may feel as though they are owed more for their work, but they must establish their value before the raise or promotion happens. The goal is to avoid unmet expectations in all areas of business, whether it's between the contractor and the client or the employee and their manager. Maintenance services are not very profitable, but you can maximize the profitability of PM jobs through efficiency and thorough cleaning/inspection. Service repairs are difficult jobs when it comes to profitability. At Kalos, we struggled with service repairs because we never anticipated setbacks in our original price quotes. We experienced additional expenses that we didn't initially factor into our repair pricing because we failed to prepare for extra parts, trips back to the shop, etc. Moreover, we used to try to squeeze lots of value into a single job. As a result, we would sometimes undervalue the work we performed. You can't make more money if you don't factor your time, labor, and extra parts into the quote. Even though we wanted to have low prices to help our customers, we earned very little money compared to the work that we put into the job. We overcame that financial slump by spending more time on our jobs; we spent more time diagnosing the whole system, communicated with customers about our services' value, and spent more time fixing everything on a system so that we could charge more while avoiding callbacks. Labor MUST be expensive (but valuable) if your business wants to turn a profit. When communicating your services' value to the customer, you need to give the customer a chance to say NO to some of your services. That way, they will be much less likely to nitpick your work if they know that they did not pay for the full package of services. Profitability comes down to doing more billable work while you're at a job site. When you become more profitable, you will also have a bit more control over the customers you choose to serve. As such, it is important to pay attention to total system performance and aesthetics to attract (and keep) the customers who value your work and maximize your profitability. Profitable HVAC businesses also pursue mastery of valuable related fields, such as indoor air quality (IAQ), building science (duct design), and human comfort (humidity control). It is one thing to sell a customer a dehumidifier without knowing the science behind it, but it's a completely different thing to explain the benefits of dehumidification, traits of individual dehumidifiers, and human comfort fundamentals to a customer so that they can make an informed decision about their comfort. Instilling a value-oriented mindset in yourself and your technicians is also important for profitability. Successful HVAC businesses train their technicians how to approach money conversations. Train technicians to establish value when they communicate with the customer and not to undervalue the company's services. Make sure technicians also don't project their own opinions about the value onto customers. Technicians should be methodical yet friendly, attentive, and in tune with the customer's needs when communicating value, not lazy or overly casual. Effective business owners take what customers want and convert those to a solution; they assess their resources and tailor their plans to their customers' desires. Bryan and Jesse also discuss: Misunderstandings about tax write-offs Bundling and flat-rate pricing systems Establishing value with commercial customers Technician skillsets Maintenance contracts Warranty challenges Communicating price ranges Treating difficult clients with respect Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Thomas, Brad, and Eric unpack their toolbags and explain the tools they use on their market refrigeration jobs. Market refrigeration is a complicated branch of HVAC/R that requires several tools for a wide range of functions. Perhaps the most diverse tool group is the wrenches. In market refrigeration, the Kalos techs use service wrenches, crescent wrenches, Allen wrenches, and ratchet wrenches. Service wrenches are critical for working on service valves, which are quite common in grocery refrigeration. Crescent wrenches are best for tightening objects; Thomas keeps two on him so that he can use one as a backup. Allen wrenches work well for some service valves, hand blades, electrical components, and valve orifices. Adjustable wrenches are excellent for adapting to various TXV sizes. It’s best to have adjustable wrenches that can adapt to a wide variety of valves, as you will be working with lots of those in market refrigeration. Brad keeps 9/16” and 5/8” ratchet wrenches, which will work for almost all compressor head bolts and TXV screens, respectively. When it comes to screwdrivers, Brad recommends keeping 8-in-1 or 10-in-1 combo pack screwdrivers with varied head sizes. The most common sizes you’ll probably need to use are 1/4” and 5/16”. Nut drivers, another important tool, also come in combo packs that contain various sizes. Those nut drivers go on an impact drill, which works for the relatively limited use of drills in grocery refrigeration. Brad also keeps 1/2” and 9/16” sockets in his toolbag; Eric keeps those two socket sizes, a 7/16” socket, and an 11/32” socket. Eric also keeps locking extensions for his drill. Market refrigeration has quite a few electronic components, so our techs always carry a durable multimeter on them. Wiring is a major component of grocery refrigeration, so our techs also keep wire strippers, wire crimpers, and Channellock pliers. We also keep cool technology in our bags, including thermal cameras. Those cameras can help us locate issues with the check valve and electrical components. Eric keeps a diagnostic toolkit in his bag, including the Fieldpiece Joblink set (https://www.trutechtools.com/Fieldpiece-Complete-Job-Link-Probe-Kit-TTT-Exclusive). He also uses the Testo 605i (https://www.trutechtools.com/Testo-605i-Humidity-Smart-Probe-2nd-Gen). Our cell phones also perform several vital functions for a tech, such as calling tech support and looking up manuals. Even though we want to avoid using cell phones for purposes that might distract us, they are the key to critical information about our work. On top of tools, we also keep a few miscellaneous items in our bags, such as extra small parts or fasteners. These may include Schrader cores, screws, crimp connectors, cable ties, and caps. We also keep tape, jumpers, type K thermocouples, flashlights, and tape measures in our bags. Eric keeps valve stems in his bag, too, which are uncommonly used but VERY useful when they are needed. All of those tools help our techs get through a vast majority of their diagnoses and small repairs. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Eric Mele replaces a market condensing fan motor and describes the process. His process applies to other large condenser fan motors as well. The fan motor connects near the top of the condenser unit, quite close to the fan blade. In this video, Eric uses an attached metal flex connector to route the wires away from the fan. He has also removed the flag terminal ends, as they had worn out and made a lousy connection. Eric loosens the bolts on the motor and takes out the lock washer; he performs the latter with a magnet. He used a 5/8" wrench to spread the belly band apart and make it easier to insert the new fan motor. Some motors have screws to stop the insertion from going too far, but other motors do not; it is up to you to determine which type you have so that you can prevent the motor from falling in and hitting the coil. After Eric hooks up the high-voltage wiring, he sets the motor to "high volt." If he were dealing with a low-voltage application, he would wire and set the motor accordingly. He then puts the cover back on and makes sure the wires are out of the fan blade's way. When Eric puts the fan blade on, he protects the shaft, puts the fan blade on in the correct direction, and uses the keyway to determine the fan blade's position. When possible, you want the fan to sit in the middle of the keyway, not at the edge. Then, Eric tightens the bolts, paints over the shaft to make it stainless, and puts the shroud back on. However, he notices that the fan blade rests too close to the shroud and must lower the blade again. Before you finish any job, you will want to check your electrical components as Eric does. Check your fuse placement, the amperage on all three power legs, and the fan blade rotation. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan uses fun and inexpensive novelties to demonstrate the basic scientific principles that drive HVAC systems. These learning tools are a great way to introduce basic temperature, pressure, and motion concepts to hands-on learners and pique children’s interest in science. The first tool is a hand boiler. The hand boiler has a bottom bulb with ether alcohol. When you hold the bulb, the liquid rises to the top and may bubble. That occurs because your hand transfers heat to the ether alcohol, and the molecules begin moving more rapidly, creating more pressure in the closed space and making the liquid occupy more of that space. The hand boiler also illustrates that boiling can happen at relatively low temperatures, not just 212 degrees Fahrenheit (100 degrees Celsius). (You can find the hand boiler at https://amzn.to/3k1B1wR.) The next tool is a Stirling engine. You can put an ice cube on top of it and hold the apparatus in your hand. As you hold it, the heat from your hand transfers to the Stirling engine. When you start spinning the flywheel, it keeps going. That is because the pressure differential between your warm hands and the cool ice cube moves the bellows between them, and those bellows keep moving up and down as pressure builds and releases. The movement of those bellows turns the flywheel. (You can find the Stirling engine at https://amzn.to/3hu5W3d.) We recommend using an electrical kit with a fan motor, ammeter, voltmeter, lightbulb holders, generator, bell circuit, and more for teaching the electrical side of HVAC. The electrical kit is a fantastic way to introduce electrical basics to middle and high school students. (You can find the EUDAX electrical kit at https://amzn.to/3wuN9cr.) Another interesting novelty is the magic drinking bird. The drinking bird has two bulbs connected by an elongated glass tube. The lower bulb contains liquid methylene chloride, and the top bulb only contains invisible vapor. When the bird’s head gets wet, the water begins evaporating immediately, cooling the head. (Think about stepping into a room with a fan while you’re sweating; you cool down as your sweat evaporates.) Some of the vapor in the upper bulb condenses, reducing the vapor pressure in the top bulb. Since the vapor pressure in the bottom bulb has remained constant, the pressure differential between the bulbs will force some of the liquid will rise to the top bulb to maintain equilibrium. Then, the bird appears to drink when the top bulb gets heavy enough to tip. A similar pressure differential forces the bird back upright. If the bird has tipped its head into some water, the process will repeat itself. (You can find the drinking bird at https://amzn.to/3xBC0Ik.) Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Ty Branaman gives the Kalos apprentices a lesson on transformers, inductance, and common electrical issues. (Check out Ty’s YouTube channel at https://www.youtube.com/channel/UCIoD-SEdUWMA74tWXRMyCZQ.) The compared number of wraps from one side of an electromagnetic coil to the other represents a ratio. Each wrap of an electromagnetic coil strengthens the magnetic field of the energized iron core. (The alternating current energizes the iron core, which becomes magnetized.) The wires on the primary don’t touch the wires of the secondary because the electricity transfers via the magnetic field. There is one type of transformer where the primary and secondary have the same number of wraps. That component is the isolation transformer. The isolation transformer does a good job of “cleaning” power out and suppressing bad sine waves or electrical noise. We almost never use isolation transformers in the HVAC industry, but musical instrument amplifiers use them quite often. Transformers can “step up” or “step down” to a different voltage level. We mostly step the voltage down in HVAC, but transformers must step the voltage up in gas furnaces (up to around 10,000 volts!). Power (wattage) stays the same from one side of the transformer to the other. Remember that watts are made up of the volts multiplied by the amps. A step-down transformer may reduce the voltage, but the amperage will rise to keep the same overall wattage. Inversely, a step-up transformer may reduce the amperage to raise the voltage from one side of the transformer to the other. Transformers have a VA (volt-amp) rating, also known as a watt rating. That rating can tell you how much power it can transfer from one side to another. For example, a transformer with a VA rating of 25 will NOT have the power to step the voltage up to 10,000 volts in a gas furnace; in order to boost the voltage that high, you would be left with a fraction of an amp, which is just not possible. A fuse can protect your amp flow (which prevents blown transformers). For that reason, you should NEVER replace a transformer without adding a fuse. If you come across a blown fuse, you’ll want to figure out what killed the fuse before you add a new one. The most probable cause of a blown fuse is short to ground (such as from wire rubouts or sloppily stripping wire). Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Bryan explains how to read schematics/diagrams on HVAC equipment and walks through an example. He takes a Rheem air conditioner and compares the physical unit to its point-by-point diagram and ladder schematic. Point-to-point diagrams illustrate how each component is wired in a piece of equipment; these tend to keep the same orientation as the physical piece of equipment. Conversely, a ladder schematic illustrates the current flow from one side of the circuit to the other (for example, from L1 to L2). Ladder schematics generally show the high-voltage side on top and the low-voltage side on the bottom. Although diagrams can vary by manufacturer, there are typically a few consistent components. One of these is the presence of optional components on a point-to-point diagram. These components are NOT installed from the factory and are generally indicated by some variation of (OPT) on the point-to-point diagram. Field-installed components are connected by a dashed line, and factory-standard components are connected by a solid line. All diagrams will have notes and a legend or component code to help you interpret the schematic. The legend will help you make sense of the abbreviations you see in the schematic. (For example, it will tell you that “CCH” means “crankcase heater” or that “CHC” means “crankcase heater control.”) Notes will give you information about acceptable connections and other relevant information for wiring the equipment. On a ladder schematic, you will be able to determine the number of poles and throws of a component by looking at the diagram. A single-pole, single-throw component can only open or close. Squiggly lines underneath a component indicate a thermal switch, and a bell underneath a component indicates a pressure switch. A ladder schematic may or may not indicate the colors of the wires. If a ladder diagram does NOT show the colors, you may need to consult the point-by-point diagram. A point-to-point diagram typically abbreviates the wire colors, so you may need to check the legend or notes. (For example, “R” may mean “red,” and “BK” may mean “black.”) Point-to-point diagrams may also indicate the placement of additional parts that would also be installed with optional components, such as wire nuts. In short, ladder schematics show WHAT is connected, and point-to-point diagrams show HOW components are connected. The legends and notes exist to help you understand both diagram types. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/

Ty Branaman gives the Kalos apprentices a lesson on BTU-watt conversion using a toaster. (Check out Ty’s YouTube channel at https://www.youtube.com/channel/UCIoD-SEdUWMA74tWXRMyCZQ.) Toasters are electrical conversion devices that transform electricity into heat. However, toasters are excellent training tools because they also contain contactors, levers, and terminals that are easy to observe in action. Toasters also have a bimetal device on the inside. Bimetal devices are composed of two metals, and the device begins to warp when it comes into contact with heat. An example of a bimetal device in HVAC is the Snap Disc or snap switch thermostat. As that bimetal device on the toaster warps, it also energizes an electromagnet, which props the toast out when it is ready. So, toasters are great learning tools for HVAC apprentices because they have so many parts in common with HVAC equipment. You can essentially turn the toaster into a heater by attaching a fan to it. The bimetal device would also act as a safety device if the toaster were attached to a fan. In toasters, wattage (power) gets converted into BTUs of heat energy. Each watt yields 3.413 BTUs of heat energy. If a toaster were to use 900 watts of power, it would yield more than 3000 BTUs of heat energy. In the HVAC industry, we perform load calculations to determine how many BTUs of heat our equipment must move (such as Manual J calculations). So, hypothetically, we could use these calculations to determine how many toasters could provide heat to a home. It’s impractical to use so many toasters with fans, but the wattage costs the same regardless of if you use several toasters to heat a home or a typical HVAC electric heater. The expense will come with energy efficiency, as large HVAC fan motors have become much more efficient in recent years. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/

In this live stream, Bryan walks through electrical diagrams and teaches his apprentices how to use schematics for circuit tracing. Ladder schematics are the most common type of diagram you will see; those and connection diagrams are what we mostly use in circuit tracing. There are five main types of diagrams: ladder (schematic), point-to-point (connection), pictorial, shop drawings, and as-built diagrams. Ladder schematics are basic and include common symbols to indicate pressure switches, contacts, power supplies, loads, etc., that illustrate how equipment is wired. They are NOT accurate visual representations of the components. Ladder diagrams connect circuits from one side to another (such as L1 to L2, hot to common, etc.). In the HVAC industry, we usually work with parallel circuits, which make up the majority of the ladder diagrams we see. Series circuits may occasionally appear, but they are much less prevalent than parallel circuits. (Safeties are series of switches; they are NOT series circuits.) Point-to-point or connection diagrams are becoming increasingly common. They do not illustrate clear sides of the circuit, but they show you each conductor and where those conductors go. You can trace the diagrams relatively easily, so you can tell which components are connected. You can also tell which components are optional and learn more about the physical features of the equipment; you cannot do either of those effectively with most ladder diagrams. Pictorial diagrams illustrate circuits with visual representations of their components instead of mere lines and symbols. (Motors look like motors, not series of lines and circles.) They are uncommon because they are difficult to draw. However, pictorial diagrams illustrate the connections and the real components very well and are quite easy to work with. As-built drawings illustrate the equipment as it is built. Other schematics, especially point-to-point diagrams, illustrate optional components. Crankcase heaters are common optional components that you would see on a point-to-point diagram but not an as-built one. Therefore, component identification is a major skill for reading all types of schematics. Bryan also covers some common symbols on diagrams. One common symbol is a bell (pressure switch). Pressure switches remain closed until a pressure change opens them. Most safeties are single-pole, single-throw. Contacts show up as gaps on schematic diagrams. A normally open contact will be a mere gap, and a normally closed switch has a slash through the gap. Little circles usually represent relay coils, but squiggly lines may also represent relay coils. A capacitor is represented by a gap with one straight line and one curved line on each side of the gap. Arrows indicate time delay circuits. When it comes to learning schematics, a good exercise is to take apart scrap units and rewire them from scratch with help from the schematic. Learning schematics takes time, patience, and lots of repetition with various equipment. Remember, always read the manual, check the notes, and refer to the legend! Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.

Watts is the measurement of power in an electrical system. Watt’s law states that you can determine the number of watts in an electrical component by multiplying volts by amps. When people say that a machine is “using more energy” or “using more electricity” than it should, they are referring to the number of watts the machine is using. (Check out Ty’s YouTube channel at https://www.youtube.com/channel/UCIoD-SEdUWMA74tWXRMyCZQ.) Ty performs an experiment with a heater to teach the apprentices about Watt’s law in action. He connects the electric heater to an adapter that displays the voltage and amperage of the device. The apprentices multiplied the volts by the amps to yield about 913 watts. The resistance, on the other hand, was quite low; the multimeter only measured about 13 ohms of resistance. The class performed a second experiment using an iron. The iron also had 13 ohms of resistance, but it put out slightly more heat, about 994 watts. Although the iron and the heater have different applications, they are the same at the core. Both the iron and the heater are electrical conversion devices. They convert electrical energy into heat energy, and higher wattage will generate more heat for both appliances. The voltage will drop when other appliances begin running. The voltage may also drop when the wires are not large enough to feed the current to the home or the appliances. These voltage drops can lead to electrical failure. So, when components that utilize electricity fail much more frequently than usual, the problem could originate from improper wire sizes. You may not see issues with the wire sizes until you check the volts and watts of a component under load. Make sure your diagnostic process includes taking your watts and voltage readings under load to avoid some embarrassing misdiagnoses. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/

Ty Branaman teaches the Kalos apprentices about magnetism and electricity with analogies. (Check out Ty’s YouTube channel at https://www.youtube.com/channel/UCIoD-SEdUWMA74tWXRMyCZQ.) You create electricity when you send a magnet through a coil of wire. Alternatively, sending electricity through a coil of wire creates a magnet. Solenoids are prime examples of electromagnets and are quite simple to create and analyze. Motors also use electromagnetic force to function. A motor may have several electromagnets, and the current flow changes direction. We call that reversal of current “alternating current” (AC). When you measure a condensing fan motor’s amperage with the clamp on your ammeter, you don’t measure anything on the wire itself. Instead, you measure the magnetic field from the electrical current. Motors also have varying numbers of poles. In HVAC, we often see 6 and 8-pole motors. On a motor, each pole acts as a stator that turns the rotor in the center. In general, the fewer poles you have, the faster the rotor will turn. A good experiment to demonstrate the effect that poles have on rotation speed, as Ty shows, is to have several people work together to spin an office chair. Start with 8 people (stators) around the chair (rotor). Then, subtract 2 people after a few spins. Repeat. You will notice that the chair spins faster when you remove people. However, the number of poles on a motor impacts the resistance of a motor. Power (watts) is a different measurement entirely. To get the watts or power measurement of an electrical component, you multiply volts by amps (V x A). As such, you will have greater power (more watts) when you have lower resistance and higher amperage. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/

Ty Branaman gives the Kalos apprentices a lesson on compressor diagnosis. (Check out Ty’s YouTube channel at https://www.youtube.com/channel/UCIoD-SEdUWMA74tWXRMyCZQ.) Ty came across a shorted compressor on a service call with one of the Kalos techs. However, the diagnostic process had just begun. For Ty, it’s never enough to know WHAT is wrong; he has to know WHY it went wrong, too. When a compressor shorts, the resistance will be low, and the electricity will move from line 1 to line 2 so quickly that it trips the breaker. Before making a hasty diagnosis, it is best practice to confirm a short by ohming out your compressor with your meter. The resistance will read much lower than normal. Then, you can be sure that the compressor is shorted. Grounding out is a possible cause of a shorted compressor. You can tell that compressor is grounded out when electricity flows from one of the lines to a piece of metal. In a grounded compressor, the electricity shortcuts to the metal casing, not the windings. When that electricity flows too quickly, the windings get too hot. The varnish on the winding bakes off and allows the electricity to flow faster and get even hotter. It’s a surefire recipe for a shorted compressor. You can also confirm a shorted compressor by turning the unit on without the compressor and seeing if the breaker trips. If the other components turn on without the breaker tripping, you can confirm that the compressor is the culprit. Burnouts are another cause of compressor failure. The refrigerant or oil quality can tell you if you’re dealing with burnout. You can typically sniff for a pungent odor to tell if there was a refrigerant or oil burnout. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/

In this video, Eric Mele shows how to use a 10-wrap wire rig to amplify low voltage and condensing fan signals for more accurate current measurements. To make a 10-wrap rig, you simply take one strand of wire and wrap it to make 10 individual strands in a loop. You can put an ammeter clamp anywhere on it and get a more precise amperage measurement than your meter allows by using a little bit of math. When you measure the amps on a rig with 10 wraps of a single wire, the amps of the wire itself are multiplied by 10. Thus, when you apply your ammeter clamp to the 10 wire rig, all you have to do is take the measurement and move the decimal point to the left to determine the amperage of a single wire. The 10-wrap rig also isolates the wire and makes you less likely to pick up amperage from other nearby wires. For example, you could check the amperage on a condenser fan motor and yield 1.1 amps. When you use a 10-wrap rig, you will get a measurement like 11.8 for the wire with 10 loops. You move the decimal point over and get an amperage reading of 1.18 for a single wire. That's a lot closer to 1.2 than 1.1, and that extra precision can be quite helpful. We use #14 wire with male and female spade connectors in this video. Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/

Trevor Matthews, Eric Kaiser, Don Gillis, and Jim Bergmann join Bryan for an educational live stream about compression ratio, efficiency, and capacity. They also touch on sensible heat ratio (SHR) and the conditions that affect SHR and compression ratio. Compression ratio is the ratio of head pressure to suction pressure in an HVAC/R unit. Generally, compression ratios approach 2.5:1 on high-efficiency, 16+ SEER A/C systems. The highest compression ratio in A/C compressors is typically 11:1. Refrigeration compression ratios tend to be quite a bit higher (up to 26:1). To calculate a system's compression ratio, you take your suction and discharge pressure right by the compressor. Then, you turn them into absolute readings. To do that, you add atmospheric pressure (14.7 PSI) to your gauge pressure reading. You divide your head pressure (discharge pressure) by your suction pressure to yield a ratio. When you pump down a scroll compressor, the floating seal prevents a system from running with too high of a compression ratio. High head pressure AND low suction pressure both contribute to high compression ratios. Lately, air conditioning manufacturers have attempted to drop compression ratios by increasing the sizes of their condenser coils. Increasing the sizes of condenser coils helps expand the surface area; when that happens, you can get the refrigerant temperature closer to the outdoor ambient temperature. (As you could probably assume, outdoor ambient also affects compression ratio.) While those reduce head pressure, they don't do anything to address issues about low suction pressures. Mass flow also plays a role in compression ratio. It correlates with the suction and discharge pressures. Higher discharge pressure indicates lower mass flow, and higher suction pressure indicates higher mass flow. Compressor ratio and efficiency go hand-in-hand. Scroll compressors tend to have lower compression ratios than reciprocating compressors and are more efficient. Reciprocating compressors retain some gas in their pistons; the retained gas expands after most of the discharge gas leaves, leading to inefficiency. Sizing is also a vital component of the compression ratio. Oversizing, in general, is NOT a best practice in installation. (You can see the benefits of large evaporator coils in dehumidification and large condenser coils in reducing compression ratio, but they are not perfect fixes and can lead to other complications.) Suction filter/driers are often improperly sized and end up being too restrictive. Improperly sized suction filter/driers have the same effect as a kinked suction line, which horribly impacts the compression ratio. Sensible heat ratio (SHR) indicates the amount of humidity removed from an airstream across the evaporator coil compared to the sensible heat. Essentially, it compares latent heat to sensible heat and is expressed as a percentage of sensible heat. It typically does NOT impact the compression ratio, but conditions that affect the SHR may also affect the compression ratio. When it comes to capacity, we often encounter limiting factors in each system. There may be difficulties rejecting or absorbing heat. Additionally, not all latent capacity can be converted to sensible. So, increasing airflow won't directly increase your capacity because of that inconvertible latent heat. We also answer viewers' questions and talk about: Vapor injection Theoretical (and real) ways to reduce compression ratios with water Dirty evaporator effects on volumetric efficiency Dew point and its impacts on SHR and suction pressure Manual J and latent heat load MeasureQuick testing and functioning Noisy compressors Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/

In this video we use probes, measurequick and tees to charge a txv system using the subcooling method. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video Eric Mele finds some poor and loose compressor connections from the factory so he makes a field improvement. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video we show how to remove or recover refrigerant from a running air conditioning system to hit a target subcooling using an analog manifold and a line clamp thermometer. We also cover how to evacuate and weigh the tank as well as water capacity and tare weight. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Rachel Kaiser gives an amazing presentation on all the stuff we wish we knew to make understanding HVAC science easier for us to grasp. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We think that the trades are are great opportunity for young people who don't prefer college and we used this video to promote this at the 2021 FPEA conference for home schoolers. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Eric mele replaces a market refrigeration condensing fan and describes the process. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We test multiple leak detectors at once and learn that ultrasonic works better than I originally thought. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video Eric mele rewires DC fan controls to prevent some issues in market refrigeration. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Join Bryan and Eric to learn about diagnosing an open ac compressor overload along with causes, cool down and testing. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We cover the assembly and disassembly of a Westermyer and Sporlan oil filter as well as show the horizontal/ vertical mounting assembly. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

This 3D video shows how to charge a TXV air conditioner or heat pump using the sub cooling method with standard analog gauges. Learn to charge an R410a AC unit using subcool. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

How to tap a transformer for 208 volts instead of 240 volts on an air conditioning system installed in a commercial application featuring Eric Mele. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

How to troubleshoot a shorted contactor coil in the HVAC field. Find the video on AC Blown Fuses here: https://www.youtube.com/watch?v=61YBG2e04wk&t=3s Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this quick class we cover run capacitors, how the are rated, how they are tested and how they work. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We show using an ohmmeter for continuity tests on switches as well as measured resistance on loads and I make a SUPER DUMB mistake. See if you can catch it before I announce it. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

How do you improve your customer's health as an HVAC Contractor? A good friend of HVAC school Joe Medosch answers this and more in this lecture. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video we test a dual run capacitor that SEEMS to show a higher microfarad test measurement than the rating, but we discover something interesting. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Tony with Fieldpiece gives real world examples of how to use modern hvac tools for accurate measurement and diagnostics. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We show how a low voltage fuse works to protect the low voltage circuit in am air conditioner. How to use a volt and ohm meter to test and how to inspect the system for the cause. Check out our 208V vs 240V video here: https://www.youtube.com/watch?v=r3hSaiIt8-Y Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

David Richardson from NCI talks Combustion Air Myths and more. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com​

In this video we show some some very basic uses of a volt meter for safety and diagnosis for new apprentices. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com​

In this presentation from the 2nd Annual HVACR Symposium, Jim Bergmann with MeasureQuick covers how to commission and test a new gas furnace. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com​

Bryan and Bert talk about how to properly maintain ductless minisplits... or at least the way we do it. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com​

Ricks Sims from FRACCA shares his years of experience with condensation and duct sweating as well as more fun with the water molecule is this eye opening session. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com​

In this session from the 2nd annual symposium Eric Kaiser shares his knowledge on how to effectively measure static pressure and what you can do with it to solve system airflow problems, set airflow and select filters. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com​

In this video we cover all of the components that are common to a heat pump air conditioning system as well as some of the basics of how they operate and what they look like. This is a great intro to heat pumps for a new student or apprentice to get a sense of all the components and where they are located Including Compressor Discharge Line Condenser Liquid Line Metering Device / TXV / Piston Evaporator Suction Line Reversing Valve Accumulator Liquid Line Filter Drier Suction Line Service Valve Liquid Line Service Valve Schrader Core Suction line filter drier (not shown) Transformer 5A Fuse Thermostat wires / control wires Safeties (Low pressure, High Pressure, Condensate overflow switch) Thermostat Blower Board Defrost Board Contactor Sequencer or heat relay Condenser Fan Blower Motor Heat Strips Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

We cover all the steps for proper rediagnosis and replacement of a leaking evaporator coil along with some common mistakes to avoid. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Don Gillis introduces a new Emerson training kit which includes a disassembled scroll compressor. No need to cut open compressors for training purposes! you can also win one of those at the Symposium! Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Bert heads over to the Fresh-Aire UV table to check out their product line, and discuss its practical uses. Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Infinicon rep introduces two new leak detectors. Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Check out RetroTec equipment including blower door, their own duct tape, duct leakage tester, pressure pan and more. Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Watch Bert and co. recover refrigerant, open it to the outside air and see how long it takes to pull a vacuum using a 2cfm battery powered NAVAC pump. Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Vacuum Race is on in the symposium! Watch 2cfm NAVAC battery powered Vacuum Pump go against NAVAC 12cfm designed for commercial pump. Feat AK HVAC. Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Check out the Testo display table at the symposium. Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

It’s lunchtime at the symposium and we are lined up around the street waiting to get some food. While we wait we pull aside some attendees to ask them how they are enjoying the training. Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

We meet with some of the guys at NAVAC As we get a quick demonstration of some of their new tools. Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Join us on 3/11 – 3/13 2021 for the 2ND annual HVAC/R training symposium. This will be a structured conference with classes and demos going on throughout each day from 8AM to 5PM with opportunities to hang out along the way. You will come away with new relationships with the best in the trade as well as some excellent training. Go to hvacrschool.com/events to find out more.

Craig and Bryan have a frank discussion on when nee tools do and don't make sense. Visit AC Service Tech website at: https://www.acservicetech.com/​ Find Craig's channel here: @acservicetech Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

We discuss all the air conditioning and refrigerationleak detection methods including ultrasonic, nitrogen standing pressure, heated diode and infrared as well as our experiences and best tips for finding refrigerant leaks. Visit AC Service Tech website at: https://www.acservicetech.com/ Find Craig's channel here: @acservicetech Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this meeting we discuss how to be more efficient in our daily routines by streamlining the order of functions in our tasks along with the scope of focus needed and tips from lead installers. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Some of the most common errors we see When A/C Techs and installers attempt to remove schrader cores for recovery and vacuum. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Guest speaker Craig Migliaccio goes over a ductless mini split system and how it functions in heating mode. Visit AC Service Tech website at: https://www.acservicetech.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

AC Service Tech and HVAC school collaborate to give new HVAC applicants some top tips for starting out a fulfilling career in HVAC (heating, ventilation and air conditioning). Visit AC Service Tech website at: https://www.acservicetech.com/ ​ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Bryan and Craig from ac service tech talk about what we have learned about swaging, flaring and deburring hvac system copper. Visit AC Service Tech website at: https://www.acservicetech.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Guest speaker Craig Migliaccio goes over a ductless mini split system and how it functions in AC mode. Visit AC Service Tech website at: https://www.acservicetech.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this meeting we discuss weighing in refrigerant to a new installation with some of the specific numbers as well as sizing a liquid properly and how to find that information. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this video we talk through refrigerant in the condenser and what subcooling tells us and why that matter for troubleshooting and charging a refrigeration or air conditioning system. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this step by step 3D animated video we show how to remove a blower wheel and blower motor from an air conditioner air handler and clean it. This video includes disassembly and reassembly/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Craig from AC Service tech joins us and shares some of his knowledge on TXVs and shares his concern about techs swapping them with pistons. Visit AC Service Tech website at: https://www.acservicetech.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

5 things that many hvac techs miss about ac run capacitors and how a run capacitor works. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Ethan from Kalos shows some of his best tips for cleaning a common drain and preventing drain related callbacks. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Craig with AC service tech reviews a high efficiency gas furnace with sequence of operation and some important facts to know. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

The HVACR Training Symposium is happening on 3/11/2021 - go to hvacrschool.com/events to find out more. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

We review hvac motor overload, reasons it happens, how to prevent it and what to do about it as well as low pressure and high pressure switches and furnace safties. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

It is common for techs to mix up compressor common with capacitor common or transformer common. Be uncommon and don't make these common errors. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this confessional we look at ways I've failed as a leaders and what good leaders should avoiding in an HVAC business. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this video we review the HVAC School app tank fill calculator and how to use it to prevent the overfilling of refrigerant recovery cylinders. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this video we cover how to replace a condensing fan motor also called the condenser fan motor as well as many tips to prevent common air conditioning motor issues. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Attention Service Technicians and Installers! In this video Bryan explains How to Braze Air Conditioning Copper. Harris Brazing Guide: https://www.harrisproductsgroup.com/~/media/Files/PDF/Requested%20Resources/GuidetoBrazingandSoldering.pdf Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In another one of our animated how to videos Bryan explains How to Leak Test an AC With Nitrogen Pressure. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this video we cover traps, cleanouts, vents, pitch and switches for condensate drains. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

We cover some common and very silly mistakes we can all make as well as ways to prevent them and what to do to succeed in hvac as a new tech. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this short and simple video we cover some quick tips for installing a disconnect properly. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Why does a Hard Shut Off TXV Close? Under what circumstances does it close? Learn this and more in this short video. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this group service meeting, we discuss the reason why the system ends up overcharged and how to think about charge, charging, and weighing in refrigerant differently.

A quick video on two different gas valves: a Standard and Gemini Furnace Valve. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

A Quick overview of Reversing Valve on Heat Pump System. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

We cover what TD and delta T are in HVAC/R language as well as why they get confused and how to use the terms productively. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Bryan is back with the a short guide of How to Install a Thermostat. In this video Bryan covers Carrier, Ecobee, Nest, Honeywell equipment/thermostats, tips for how to wire the thermostat, avoiding blowing a fuse and more. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this video we show how to use a Schrader Core Removal tool for Evacuation (Vacuum), Recovery and when the core is damaged - WE give some best practices to get the core in and out easily every time. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Bryan talks freezing in an air conditioner and specifically freezing in an air conditioner. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this brief video Bryan explains How to Measure Total External Static Pressure (TESP) with a manometer as well as some of the things to look for when diagnosing high static pressure. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

We cover why a TXV goes fully open when there is a vacuum or no refrigerant in the system- we cover the txv forces including the bulb and and external equalizer Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Techs often have confusion over what is displayed on a Manometer Screen. In this short vid Bryan explains the different measurements on it. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Fusite is a trademark name by Emerson commonly used to describe the electrical pass through for refrigerant cooled compressors. We cover some of the safety and practical considerations regarding Fusite. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

We show how a biflow filter drier works for heat pump use. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

We review recovery and service practices on R32 and discuss the new “modular trainer” initiative. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Bryan shows a corroded Contactor that is stuck. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this quick video Bryan talks the difference between 208 volts and 230/240 volts. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

How to find a good job? How to get into the trade? Struggling to find skilled people? Bryan answers all these questions and more in this video. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video we cover open and closed refrigeration as well as isolated systems and the differences between each Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan talks differences between 3-Phase and Single Phase. Dual Voltage and Part Start 3-Phase Motors: https://www.youtube.com/watch?v=53_hGlAYP0E&t=73s Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this meeting, we discuss the basics of measuring and setting gas pressure. The importance of understanding your manometer and zeroing it correctly as well as some of the other top Gas safety tips and practices. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this class for Lake Technical Apprentices, we are doing some NATE electrical review thanks to RSES.

Make better threaded connections with air, water, gas and glycol with one new AMAZING product from our friends at Refrigeration Technologies - NYLOG White Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Bryan is back with basics of Common, Start and Run as it relates to Single Phase PSC motors. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

After some technical difficulty we talk about Business, drain slime, system efficiency and more...

In this video we show the new NAVAC flaring tool and flare gauge for making perfect flares every time with no guesswork. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Eduard is back to show you How to Build a Sheet Metal Coil Case From Scratch. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this meeting we look at how to choose the right air filter by considering size, depth, MERV, measured and system static pressure. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

I’m this review of terms from the Lake Technical College Apprentice program we review open and short circuits - Make and Break - Normally Open and Closed - Switches - Loads - Power Supplies and Conductors and More Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this Kalos Meeting, we discuss what the team sees as the #1 key function we perform in an HVAC Service business to ensure consistent success. Is it knowledge? training? quality? TXV? you will have to watch to find out

Bryan discusses reasons a motor is running hot or inefficient and things that are done on maintenance/service calls that can help solve the problem. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan talks through the entire basic refrigeration circuit using a Hamden R123 trainer. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

HVAC School has reached 100k subscribers!! We wanted to thank you all and bring you a compilation of Top HVAC Tech Tips from some talented HVAC Techs. Featuring Eric Mele, Andrew Greaves, Sam Behncke and of course Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

This video covers the weight and enthalpy impacts of humidity (water vapor, moisture) in the air. We discuss the weights of various molecules and how and why we are mistaken about the impact water vapor has on the weight of air. We discuss relative humidity, dewpoint, mass, volume and more... all related to understanding air better. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this video Home Performance Unicorn tech and owner Genry Garcia shows us how to check home pressures to find issues using a precise manometer and more Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Eduard is back with another onsite demonstration. This time he shows how to Make Field Transitions on Prefabricated Metal Duct. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Eduard shows us more practical metal duct work skills by installing a rectangle to round transition into and existing duct riser. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this meeting tool giveaway free for all Bryan gives away some useful and odd little tools that can make the job easier and talks a bit about each one. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In Bert’s second ever substitute class he reviews more tank safety practices and then dives into the basic Refrigerant Circuit. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Kaleb goes through the process of Heat Rise Airflow Calculation. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Bryan demonstrates a in-depth tutorial on how to set a refrigerant charge by Subcool. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Kaleb is joined by joined by Hunter to do some test calls to to BLUON Tech Support Line. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Nick Comparetto from Comparetto Comfort Solutions is back with a tutorial of making a High Quality DIY Box Fan Air Purifier. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Bert is acting as a substitute teacher at Lake Tech, and covers some recovery safety, tank safety, and electrical safety... and of course, hijinks. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Kaleb presents a companion video piece to his article on Dielectric Grease Wiring. You can find the article here: https://www.hvacrschool.com/dielectric-grease-what-it-is-and-how-to-use-it/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Bryan brings you a video which is unlike any other videos on HVAC school channel. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Being a successful HVAC tech takes many of the same disciplines it takes to grow in any career and in personal life. This meeting covers some big areas where discipline is critical. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Kaleb and Bryan demonstrate making a Double Crimp Connection. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Another great Tech Eduard Khachaturyan joins us to show how to Fabricate a Metal Supply Plenum From Scratch. Here are some links to the tools in the process: Folding tool (in New Jersey we call them clip bender) https://www.trutechtools.com/Malco-12F-12-Folding-Tool-305-mm-38-in-95-mm-and-1-in-254-mm-bending-depths.html I don’t know how they are called we call them “big ass snips” https://www.trutechtools.com/Malco-M14N-Andy-Straight-Aluminum-Handle-Snip-14.html In the video I used Midwest brand but true tech tools doesn’t carry them, however they have Malco ones which is also great snips I just like midwest more, fits better in my hand. We call them right snips or red snips but I just realize they called “Offset Aviation Snips, Left Cut” probably because you can make turn only to the left with this snips, when with the green handle ones you can turn only right. https://www.trutechtools.com/Malco-M2006-Max2000-Offset-Aviation-Snips-Left-Cut.html 1/4 chuck https://www.trutechtools.com/Malco-MSHL14-14-Magnetic-Hex-Chuck-Driver-2-916-Length.html Screw gun https://www.milwaukeetool.com/Products/Power-Tools/2750-20 Tape mesure https://www.stanleytools.com/products/hand-tools/tape-measures/fatmax-tape-measure/16-ft-fatmax-classic-tape-measure/33-716 Aluminum ladder can be used anything that has a corner (the old furnace, any old door, new plywood…) but work platforms are the best for me https://www.wernerco.com/us/products/ladders/step-ladders/360Series/364 Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Jesse Claerbout, Kalos' Residential GM, reviews the importance of delivered capacity measurement. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Kaleb is back with a Sequencer Facts video. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Kaleb Saleeby is back to demonstrate you Wire Routing & Float Switch Positioning. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Don't get overwhelmed with 3-Phase! It's not that complicated! Bryan is back with more of his knowledge this time on Dual Voltage and Part Start 3-Phase Motors. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Jason Obrzut calls in on Apprentice Program Day 1 to talk using your resources. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bert shows us how bad his van is, and why it's important to clean and organize your stuff to make doing jobs easier.

Bryan gives a quick lesson on measuring and pressures on Liquid Line VS. Discharge Line. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this class we talk about best cleaning practices for evaporators, condensers, drains, blowers and more as well as talk about the MINDSET of cleaning it takes for success. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

This is the last instalment of the EPA 808 Prep series (but don't worry Bryan has a lot more HVAC Fundamentals content coming!). Here he covers Type 3 category of low pressure appliances. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We discuss power distribution and some practical tips about 3 phase, single phase and split phase power.

Jamie Kitchen from Danfoss talks all about variable speed motor technology. Why it exists, what it does and how to think differently about the future of HVAC/R

In this short we start the conversation about "Energy? Compared to What?" where we explore all of the energy comparison examples and examples of comparison of energy. Read all the tech tips, take the quizzes and find out handy calculators at HVACRSchool.com

In this team meeting, Bryan talks condenser fan motors, blower motors, and some considerations when replacing them. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan continues EPA 608 Prep series with a presentation on Type 2 machines. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this meeting we discuss some best practices for installation of flex ducts. Thanks to the Air Duct Council, Neil Comparetto and Michael Housh for source material. Installing ducts, sealing ducts as well as routing and strapping all get covered in this class / meeting

HVAC apprentice Josh Clemente relives his first week in the field, and tells all about having to spend copious amounts of time with none other than Bert as his trainer.

Bryan is back with another installment of the EPA 608 Prep series. This time he gives a presentation on Type 1 machines. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan is joined by Ty Newell from BUILDEQUINOX to discuss Advanced Ventilation w/ CERV2. Visit BUILDEQUINOX website at BUILDEQUINOX.COM. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this Kalos morning meeting we talk about how to find refrigerant leaks and some of the most common mistakes techs make when they “can’t find a leak” Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

This a RAW Kalos meeting where we talk about a proper diagnosis mindset, and focus especially on compressor diagnosis and how to make sure you aren’t telling someone they need a compressor when they don’t.

Britton and Jordan rough-in a one-way Mitsubishi ductless mini-split head and review some of the basics. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan Orr gives a quick lesson in Diagnosing Open & Short Circuits. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Genry Garcia shows how to use a blower door to test for infiltration on a home/ Como usar el Blower Door para verificar puntos de infiltración en una casa Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan shares advice on how to Stop Drain Snot. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In Part 2 of the EPA 608 Prep series Bryan talks some of the most important dates in the EPA 608 history, PSI, the use of refrigerant recovery cylinders and much more! Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan Orr embarks on the EPA 608 Prep series, this is Part 1 that covers the core material of the testing Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan is joined by Eric Mele to investigate A Strange Contactor Issue. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan and the crew demonstrate how to install the new GreenSpeed Extreme. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Next in the series based on HVAC Refrigerant Diagnostic Quick Sheet Bryan talks Symptoms of Low Evaporator Airflow. Videos on Airflow from our friends at Tru Tech Tools channel: https://www.youtube.com/watch?v=rFwIYBHis7g&feature=youtu.be https://www.youtube.com/watch?v=dqPeom7qBIw&feature=youtu.be https://www.youtube.com/watch?v=m9KMKYXHyJE&feature=youtu.be www.hvacrschool.com/quick-sheet www.hvacrschool.com/5-pillars www.hvacrschool.com/terms Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Eric Mele is back to demonstrate his way of Preventing Flooding On a Walk-In Call. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan examines Symptoms of Overcharge in another video exploring HVAC fundamentals. www.hvacrschool.com/quick-sheet www.hvacrschool.com/5-pillars www.hvacrschool.com/terms To learn more about the evaporator and superheat - https://youtu.be/ZboChiHDITY To learn more about the condenser and subcool - https://youtu.be/TkpF0e7jyPs Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan does an onsite demonstration of Diagnosing and Replacing a Run Capacitor. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan examines Symptoms of Low Refrigerant Charge in this in-depth video. www.hvacrschool.com/quick-sheet www.hvacrschool.com/5-pillars www.hvacrschool.com/terms To learn more about the evaporator and superheat - https://youtu.be/ZboChiHDITY To learn more about the condenser and subcool - https://youtu.be/TkpF0e7jyPs Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video Bryan reviews some comfort basics from the RSES Nate prep presentations available at RSES.org Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video Bryan and Tony talk Manometers and their uses. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan is joined by his sister in law Shaunda to demonstrate a UV light and Petri Dish Demo. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this live stream we will take callers and talk about our favorite tools and answer questions Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan is joined by some fellow HVAC techs to demonstrate cleaning BARD and Marvair units with Venom Packs. Sponsored by Refrigtech: https://www.refrigtech.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Basic electrical terms and concepts - Volts, Amps, Ohms, ohms law, watts law, series and parallel circuits. Visit RSES website here: https://www.rses.org/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

If you know us you know this won't be a class on how to sell but rather an honest look at how to do honest business without relying on hype or tricks. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Another duct video from Neil Comparetto. This time he shows how to cut and install a Rectangle Duct Connection. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Neil Comparetto is back to show How to Make a Leak Free Canvas Duct Connector. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We will have an open discussion of readings to take during a system commissioning, what they mean and how to use the latest tools and software to take them. We MAY also be joined by MeasureQuick founder Jim Bergmann as well as taking your calls. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan shows how to use the new Fieldpiece Joblink Manometer set to checkout Blower Settings. Fieldpiece website: https://www.fieldpiece.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We are talking all about recovery best practices for speed, safety, saving money and at the end a really GREAT giveaway. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Introducing the Fieldpiece Joblink Manometer Set! Fieldpiece website: https://www.fieldpiece.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We talk pricing and P&L reading to help people understand why markup is a nightmare Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Two of the best minds in the HVAC industry, Neil Comparetto and John Semmelhack join forces to test out a High Performance HVAC Installation. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

The team from Bluon Energy discusses retrofit best practices and considerations Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We talk all of the myths and controversy submitted by you on facebook Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Talk through grocery and market refrigeration with three great techs along with talk about ERVs, split condensers, oil pressure and many other basics. Featuring Bryan Orr, Nathan Orr, Jeremy Smith and Kevin Compass. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We bust some of the most common confusions surround volts, amps watts and ohms law Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Kaleb and Hunter show how to install Rectorseal RSH 50. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan shows how to set up Residential Demand Ventilation with Laser Egg. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Check out DUCTLESS Control and Humidity Hack with Cielo Breeze. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Break R or Y? Does a 5A fuse protect the Transformer? Which wire should you break with a float switch and why do transformers fail with a 5A fuse to protect them? Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video Bryan reviews some comfort basics from the RSES Nate prep presentations available at RSES.org Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Rectorseal RSH 60 VMD Installation Surge Protector demonstrated by Kaleb. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan Discusses Kalos COVID-19 Protocol as well as what we have leaned + Ask Him Anything Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In another HVAC School livestream Bryan and Michael Makara review Commercial Install. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Cloth masks can be used for COVID-19 prevention. Bryan's family shows you how to make one using HEPA Pocket Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In these dangerous times indoor air quality is more important than ever. Kaleeb shows you how to make Indoor an Air Cleaner the cheap and easy way! Hayward Score DYI Box Fan: https://www.haywardscore.com/articles/boxfan/ Smartairfilters DYI Box Fan: https://smartairfilters.com/en/blog/how-to-make-diy-air-purifier/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Another livestream with Bryan and friends. This time they discuss Electrical Diagnostic Thinking. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Some NATE prep basics on keeping people comfortable from the RSES NATE prep presentations available at RSES.org Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

The new range of Venom Packs from Refrigeration Technologies is out! Bryan introduces and reviews all four product within the range. Sponsored by Refrigeration Technologies: https://www.refrigtech.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan streams an in-depth presentation on 5 Install Mistakes that Kill Systems. A must watch for everyone who wants to keep their HVAC systems Safe & Sound. Check out Bert's video on Flowing Nitrogen: https://www.youtube.com/watch?v=N2eCbXCZ8kM&t=310s Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Ron Saunders of Fresh-Aire UV Joins us to Talk UV and More. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan Orr streams a podcast on UVC Air Purification from the studio where he is quarantined. Featuring Michael Housh and others Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Michael Housh from Housh Home Energy Experts shares with HVAC School. This is an detailed demonstration of how to Make a Metal Duct Transition in the Field. Checkout Housh Home Energy Experts: https://www.houshhomeenergy.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this instalment of RSES NATE Prep Bryan covers Reversing Valves and shows some very informative pictures and diagrams. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bert is back. He is cleaning coils. On a Sunday. Enjoy! #BERTLIFE Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Kaleb goes through the instructions of Liquid Line Solenoid use on Long Refrigerant Lines. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In our new series Bryan uses some resources from RSES NATE Prep to do some quick videos full of useful HVAC tips and data. Part Two covers Condensing Unit Install Practices. Visit RSES website here: https://www.rses.org/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In our new series Bryan uses some resources from RSES NATE Prep to do some quick videos full of useful HVAC tips and data. In the first instalment Bryan discusses Motor Types. Visit RSES website here: https://www.rses.org/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Jim Bergmann shows us HVAC Advanced Combustion for Furnaces and more using BluFlame from AccuTools. Learn how to avoid CO2 exposure from a real expert! Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Jim Bergmann gives a talk about Advanced MeasureQuick Diagnosis at the HVACR training symposium. His knowledge of the app is second to none and this is a real in-depth session. More info on MeasureQuick https://www.measurequick.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bert is back! He uses a setup he made for Jim Bergmann to show ya'll How to Flow Nitrogen While Brazing. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Don Gillis and Trevor Matthews show how to tear down a Compressor. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Don Gillis and Trevor Matthews are two HVAC training specialists. Together they do a deep dive into Compressor Facts and Troubleshooting. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube.

Don Gillis is Educational Services Technical Trainer. He explains the basics of CO2. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan demonstrates what's inside a Scroll Compressor. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bert deals with a Shorted Compressor that is tripping the breaker. When a compressor grounds out it generally trips a breaker or blows a fuse. We explore the full diagnosis. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

The Supco Redfish iDVM550 Power Quality Meter includes a function with which it can measure real-time power factor on a load. In this video, learn how using power factor to test capacitors under load is a valuable feature, and how to use the Redfish iDVM550 to do it! Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan gives a quick explanation of the Carrier Straight Cool Schematic and wiring connection diagram. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan explains and demonstrates how to charge during low outdoor ambient w/ Charging Jacket. Sponsored by Fieldpiece: https://www.fieldpiece.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bert and Jesus test NAVAC NRDD Digital vs. Appion G5 Twin in Recovery Machine Speed Race. Sponsored by NAVAC: https://navacglobal.com/ Bryan Orr's article on Recovery Tank Capacity: https://www.hvacrschool.com/important-recovery-tank-handling-information/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bert shows why sometimes what’s growing on the outside of ducts it vent (mold?) isn’t always on the inside of the duct Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this short video Bryan Orr shows you the inside of a Sequencer. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

BERT IS BACK #BERTLIFE - Bert finds a shut off breaker, some thermostat issues and gives a sermon on distracted diagnosis Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan demonstrates cleaning large coils with CoilPro. Sponsored by Goodway https://www.goodway.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan solves Smelly Ductless System problem using Refrigeration Technologies products. Refrigeration Technologies: https://www.refrigtech.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan explains how Inductive Reactance functions in Real Life. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school has reached 50K Subscribers! To celebrate Bryan shows around his studio and answers some tough but fair comments Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan gives an in-depth guide to dealing with compressors that won't run diagnosis. Copeland Mobile App: https://acmobileapps.emersonclimate.com/CopelandMobile/#divLoginMain Compressor teardown class with Mike Niper: https://www.youtube.com/watch?v=3aVMfR4QLgc&t=904s Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan shows how not to make dangerous mistakes when working with Blower and Heat Strip. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan does an in-depth review of how to adjust a TXV, TEV or TX Valve. Why adjust a TXV and how to tell if a TXV is working. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan Orr goes over some of the raunchiest (sounding) terms in HVAC/R. Air conditioning isn’t as dirty as it sounds. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Jayson Hines demonstrates how to update Fieldpiece Joblink Firmware. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan demonstrates thermocouple Temperature Clamp Calibration using a bowl of ice and SM380V SMAN from Fieldpiece. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan teams up with Jesse to cover the important subject of sweating ducts, dripping vents and grilles and condensation on air conditioners. Here are some other great sources for information on this topic Videos from Retrotec on Blower Door and Duct Testing https://retrotec.com/youtube/gallery/ The energy conservatory https://energyconservatory.com/ Ultra-Aire Dehumidifiers https://www.ultra-aire.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Erich Vinson joins HVAC school to show how he unclogs a difficult drain and we briefly discuss the aluminum coils drain issue and the MINDSET of proper cleaning. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Kevin Compass joins HVAC School to show us through a CO2 refrigeration booster rack with its primary components Podcast w/ Emerson on CO2 https://www.hvacrschool.com/co2/ Podcasts w/ Hill Phonenix on CO2 https://www.hvacrschool.com/critical-and-triple-point-w-rusty-walker-podcast https://www.hvacrschool.com/3-flavors-of-co2-w-rusty-walker-podcast/amp/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

How and when to consider replacing an ac contactor and some of the factors involved in the diagnosis of an air conditioning contactor. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We installed 3 Carrier Infinity Systems and an UltraAire SD12 Dehumidifier and show the results Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan goes deep into how to evacuate or "vacuum" an air conditioner in a video collaboration with Paul from The Engineering Mindset channel. 🏆Check out Pauls video on how a vacuum pump works here: https://www.youtube.com/watch?v=pnqXEnn3DNk&feature=youtu.be We take a deep dive into how to connect vacuum pumps, micron gauges, remove cores and much more to show you start to finish how to pull a deep vacuum on any air conditioner or refrigeration equipment. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/ The vacuum pump shown in this video is the NAVAC NRP8DI - https://www.trutechtools.com/NAVAC-NRP8Di-Vacuum-Pump Micron Gauge Shown is the BluVac Micro - https://www.trutechtools.com/Accutools-BluVac-Plus-Micro-Wireless-Digital-Micron-Gauge Vacuum Hose Kit and Core Removers is the BluVac TruBlu Advanced - https://www.trutechtools.com/Tru-Blu-Advanced-Kit-BluVac-LTE Core Depressor - S10767 - https://www.trutechtools.com/Accutools-S10767-Shrader-Depressor-Tool-1-4x1-4 Watch More of our Videos Funny Videos from the Life of a Tech - https://www.youtube.com/playlist?list=PLjmMtP2_3aVt8i7Z1o9PmYen4XgC_X6QX Pressure and Temperature Basics - https://youtu.be/Y2ex2OxIXT0 Make Flare Connections that don't leak - https://youtu.be/BO7ZaLgfWTQ Air Conditioning Compressor Basics - https://youtu.be/0lfa9rm8_x8

Bryan is off to the Women in HVAC/R conference and he asks Kalos employees to document their day at the company. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bert cleans some drains and says the word drains a lot and uses pan and drain spray from Refrigeration Technologies (Which works great) Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan gives Top Tips for Hoses, Seals & Cores Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We show how to measure fan (Blower) Efficacy and what it means using MeasureQuick and RedFish Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video we demonstrate brazing and protecting a line drier using Wet Rag from Refrigeration Technologies Refrigeration Technologies: https://www.refrigtech.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

The Westermeyer team of Gary Westermeyer and Ben Quade joined us at Kalos HQ and covered oil management with a focus on oil separation technologies in refrigeration. Find Out More at - http://www.westermeyerind.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Clayton Peeples shows how to use 45% Silver solder to braze Steel and Copper. Bryan explains the difference between his and Claytons approaches. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Austin takes a simple look at Freon, what Freon is, what it does, where it goes and if Freon is becoming illegal. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan covers the most common newbie mistakes when diagnosing compressors. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan asks the all important question: What should the Air Delta T be? Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan shows the best ways to find Target Superheat including using charts, apps and other resources. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video Bryan dives deep into Suction Line Temperature. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan explains all about Condenser Discharge Air Temperature. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan explains all about Liquid Line Temperature. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

A quick way to remember dew point and bubble point that you won’t forget to make it easier to work with refrigerant blends. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Norman S. Wright was kind enough to host my class in Oakland, Ca and Donald Falese gave me a quick walkthrough of their excellent VRV training center. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video we go step by step into how we make flares with a flaring tool for a mini-split ductless air conditioner including NAVAC flaring tools, deburring, torque wrenches and more.. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

This videos will help you understand what occurs to the refrigerant inside the compressor and why the temperature changes so radically from the suction line to the liquid line. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video, Travis does a maintenance on a Carrier Infinity heat pump. SPEEDCLEAN: https://www.speedclean.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this first ”HVAC Science Basics” podcast. Austin explains that air is stuff... And tells stupid jokes. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan Orr repairs an AC system with a Buck and Boost. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan Orr explains Refrigeration Rack Overview w/ Sped up Oil Change on a grocery store. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan Orr shows how to use Speedclean Condenser Needle to clean a coil without removing the top. https://www.speedclean.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan shows how to use NAVAC NRDD Recovery Machine. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Mike Nipper from Copeland teaches a Compressor Teardown Class at HVAC school / Kalos offices. presented by: https://www.emerson.com/en-us Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Leslie Orm shows us how to deal with a common refrigeration TXV issue. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Kalos GM Jesse goes over the setup and wiring of a Honeywell Focus Pro thermostat for a basic system. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We clean a grocery produce case with CoilJet, Dry Steam and Refrigeration Technologies food safe cleaners https://www.speedclean.com/ https://www.refrigtech.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

A common problem is humid climates and what to do about it Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Jim Bergmann, Founder of MeasureQuick shows how to charge and recover with MeasureQuick. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Jim Bergmann visits Kalos, teaches a class and rides with Bert. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Jim Bergmann, Founder of MeasureQuick shows how to confirm SEER with RedFish & MeasureQuick. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Residential System Commissioning (Kalos Meeting). Hosted by Bryan Orr. We talk the ABCs - Airflow, balancing and charge Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Before heading out on a long night of work, Bert (Jesse Testerman) stops by his sister's house for a trailer a/c repair, food, and sweet tea. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Kalos Tech Bert Testerman tries out Speed Clean's product on a dirty Blower Wheel. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video we talk about transformers, how they are rated, how to wire a multi-tap transformer and some things to watch out for. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan Orr explains how a volt meter can be used to check for voltage drops. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Outdoor air and why it matters in residential homes in humid climates. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Once again we braze aluminium to copper and We pressure test Al-Cop to 500 PSI and show how to make a “ring” for tight areas. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this two for the price of one episode, Bert and Alex Orr run some more service calls, followed up with some of the highlights of Bert's trip to Vegas. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

What is relative humidity and dew point and how does it impact human comfort. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

How heat is transferred and why is matters to an HVAC professional. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bert Testerman and Alex Orr spend the Monday riding together, taking calls, and celebrating a birthday. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Temperature, heat and what it all means and why it matters. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan Orr talks about some of the best tips to maintain healthy air for you and those in your home. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan Orr explains HVACR Metering Device Basics. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this episode we talk about the basic purpose and function of the evaporator coil. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

What an air conditioning and refrigeration compressor does, how it works and what it needs to do it’s job. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

This video is a basic overview of a condenser and what it does in air conditioning and refrigeration. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

The basic air conditioning and refrigeration refrigerant circuit explained and illustrated in simple terms. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Mat Milton and Robert Severson demonstrate the measurement and adjustment of gas pressure using fieldpiece and Testo manometers in the field. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this episode Bert diagnoses and repairs a low voltage short in the dark and does the worst caulking job in history. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We discuss some of the similarities and differences of HVAC vs. Refrigeration as a career path. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We talk about the differences between projects work and service in the HVAC/R trade and which might be for you. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

My favorite "first 4" to teach someone completely new to the air conditioning, heating and refrigeration trade. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

What are the differences and similarities between commercial and Residential air conditioning and refrigeration? We explore the traits and requirements for each. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

It is just another service call for Bert, until he makes a surprising discovery about the unit he is inspecting. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school shows the TruBlu pro kit from Bluvac as well as the Bluvac Micro and Bluvac pro micron gauges. Featuring Bryan and Sal. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Commercial and Residential HVAC Pros share their top tips for success as well as their perspective on the trade and why they enjoy it. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

What is the connection and order of experience and application vs. structured study? I share my perspective. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

This quick video shows maintenance and cleaning best practices for a micron gauge. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

We are giving up..... on posting audio podcasts on youtube. If you want to hear the podcast download the HVAC School app available free on android or the apple podcast app. You can also subscribe to the podcast on any podcast app by searching 'HVAC School. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan and Sal show how Speed Clean's cleaning tool is used to clean a condenser. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

When faced with the threat of a job loss, Bert must make the ultimate sacrifice. Professional appearance matters. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school replaces a minisplit coil and discovers an issue with the old flare connections. Featuring Matt Downey. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Sam and Jake remove and clean a Mitsubishi ductless / mini split blower wheel and show the process. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this service manual talk through episode we discuss the Heatcraft Beacon 2 refrigeration system and what it entails. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Episode 2 of #BertLife shares how important a good sniffer (and some microleak detector) can be when looking for a gas leak. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Watch Bert (Jesse Testerman) and his antics as he spends a Gee hours under a trailer doing a duct repair. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this episode HVAC school covers the why and the how of low ambient cooling and refrigeration. Hosted Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Step by step description of a residential indoor TXV replacement. Featuring James Hill . Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school goes over the sequence of furnace operation. Take it slow, it’s gonna blow! Hosted by Bryan Orr. Featuring Jason O. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school talks to John Oaks about his experience as a VRF tech in the field including branch boxes and two pipe vs. three pipe technology. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at HVACRSchool.com

This is a voice over audio presentation of the article of the same title on the HVACRschool.com website. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Jeff Montalvo shows us a commonly missed issue on Trane Voyager gas package units, how to get to it and what to watch for. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Jim gives us a year end review of all that is happening at MeasureQuick with Redfish, BluFlame, BluVac, Supco, Testo and Fieldpiece. Featuring Jim Bergmann. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Recovery, Installation, Brazing, Evacuation and charging of a pool heater with a shorted compressor. Featuring Sam Behncke. Refrigeration Technologies: https://www.refrigtech.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school talks through stack effect. What it is and what issues it causes. Hosted by Bryan Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

What is the difference between accuracy, precision and resolution. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school shows the right way to splice control cable and sensor wires in mission critical applications like market refrigeration. Featuring Alan Yanik. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school reviews how to check the charge on a Carrier in the heating mode when the outdoor temp is below 65 degrees. Hosted by Bryan Orr, featuring Jesse Claerbout. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

You just bring the heat...we got the rest covered! Everything you need for that fix, in one easy to carry kit!! Your day just got a whole lot easier... The kit comes in two varieties, includes your choice of Sil Sol 5% (Silver Phosphorus Brazing Rods) or Sil Sol 15% (Silver Phosphorus Brazing Rods). It also includes, what we like to call, “The Game Changer”. The Brand New, nothing like it on the market, Al-Cop Rod. This product is exclusively available in the HVAC All-In-One Kit, and once you work with it, you will never look back!* 2 Kits Available! Kit includes: Alloy Sol/Flux Al-Cop Braze (Brand New!!) Sil-Sol 56% Sil-Sol (5% or 15%) Wire Brush Watertight Cannister Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

This episode is about a simplified way to explain the basic refrigerant circuit to new techs that may help lock in the basic idea of absorbing and rejecting heat. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

John guides us through all aspects of ventilation and ventilation design with a review of point ventilation, ASHRAE 62.2, whole home ventilation strategies and much more. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school welcomes Bert to show how to clean an evap in place with Viper. Refrigeration Technologies: https://www.refrigtech.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bill Spohn joins HVAC school podcast to discuss manometers, combustible gas detectors, personal CO detectors, draft gauges and combustion analyzers. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school reviews how defrost works and how to test it in Carrier and Trane systems. Featuring Jesse Claerbout and Bill Frisbie. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school talks through all the basics of a heatpump and how it functions. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC podcast covers what you need to consider before soldering or brazing any type of joint. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In HVAC school first ever ask me anything podcast we talk about the trade as whole and answer random questions about Kalos and all things HVAC. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC podcast talks things to consider before replacing that old A/C with a bigger one. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school reviews the components of the basic heat pump and how they all work. Featuring Jesse Claerbout and Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Jason Obrzut from ESCO and Cengage comes on to talk about the vaying landscape of EPA 608 regulations with what you need to know for now. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

During an HVAC school training class something strange started happening with the COR thermostat on the wall that was worth sharing. The temperature kept rising for apparently no reason. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school introduces the anatomy of electrocution, arc flash and an intro to PPE and lockout/tagout. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school podcast discusses what is the difference between R-Value and U-Factor and why should you care. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Rusty Walker with Hill Phoenix comes on and talks about CO2 triple and critical points and some best practices for refrigeration techs working w/ CO2. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

James Bowman is back and we talk about analog vs. digital manifolds and why both of them may still have a place in the industry. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school introduces you to Frequency & Sine 101. Some easy ways to wrap your head around alternating current, electromagnetism, frequency, wave length and sine. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school shows application and technique of the AlloyBraze flux core rod by Solderweld. Featuring Bryan Orr and Sal from Products by Pros. Find out more at https://www.productsbypros.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

This video is a quick overview of how to check a heat pump in heating mode when it is below 65 degrees outside. Featuring Bryan Orr. To learn more go to https://hvacrschool.com/checking-charge-heat-pump-winter/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video we show you the NAVAC NRP8DI vacuum pump with the micron gauge on the pump and how it can be used to test your vacuum rig. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Eric Mele is back and this time we cover hot gas as a dehumidification strategy with all of the broad strokes you should be aware of. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Eric Mele is back at HVAC school to surprise us with how he changes a Trane drain pan. Eric shows his method. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video we talk about a switch, what it does and some practical wats to remember open vs. closed as well as pole vs. throw. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school shows how a basic DC motor works with the various parts. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this episode Jim Bergmann does a deep dive into combustion analysis and covers everything you need to know to keep a furnace running safe and efficient. Hosted by Bryan Orr. Chapters: 00:25:21 Marker 01 Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school reviews the three basic components to an electrical circuit and what they do. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

What is the most efficient way to connect Aluminum to Copper? Bryan answers that question today using an AL-COP Braze Rod. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this quick "Counter Training" video we talk about the features of the refco LP-88 as well as proper use of an infrared thermometer. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this part one of the two part combustion analysis series Jim Bergmann covers CAZ testing or Worst-Case Draft and Pressure Testing in detail and why it matters to techs and customers. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this episode Rusty Walker from Hill Phoenix talks through the three most common types of market CO2 systems and how they work. Secondary, Cascade and Booster. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

In this video we address the common myth that liquid line restrictions cause high head and we bust it with a few simple explanations. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this episode of HVAC podcast we talk about what it REALLY takes to setup and commission a new system properly. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Can you really trust that temperature reading? In this short episode we talk about some common mistakes techs make in making temperature measurements and what to do about it. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC School shows you the new SW-HVAK05 and SW-HVAK15 kits from Solderweld and everything they can do including copper to copper, aluminum, copper to aluminum, steel to copper and much more. Featuring Bryan Orr and Sal from Products by Pros. Find out more at https://www.productsbypros.com/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this short episode we share some quick tips about keeping panels and insulation in place. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Bryan gives a masterclass to Kalos Techs on why TXV / TEV valves are misdiagnosed, how to diagnosis them properly and how they work. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school covers the basics of how a transformer works. We cut one open and look inside a typical HVAC 40VA transformer. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

The HVAC chemist John Pastorello discusses acid inhibitors, oil enhancers, dyes and leak sealant. He shares his knowledge and some things to consider. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Brazing copper to steel is actually pretty easy. If this video we show you how to do just that using 56% silver flux coated brazing alloy by Solderweld. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Mineral and POE oils are very different and have advantages and disadvantages. In this short podcast we cover the basics. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Many technicians use hard or soft copper without thinking about which application is best for which. HVAC podcast is back to talk about where to use each as well as some hanging and strapping strategies. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this video we show how to use alloy-sol rod from Solderweld. We use it to repair a leak in an aluminum coil as well as on a U-bend. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Kevin Mayer with NAVAC visits HVAC podcast to talk all about flaring best practices step by step. From cutting, to reaming to torque wrenches we cover flares start to finish. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this episode of HVAC podcast Bryan gets feedback on a podcast topic from Andy Holt. We discuss some interpersonal and other soft skills required to be a top level technician. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com

Eric Mele is back to talk about chilled water air handlers, their valve configurations and some key things to look out for. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school explains what to check when a variable speed residential blower motor won’t come up to full speed. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school shows a common mistake techs make when replacing thermostats with dehumidification controls with those that don’t have them. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school goes over some of the common differences between analog gauges, digital manifolds (with the Testo 550) and probes. We examine the benefits of each. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

This video is for beginners to the HVAC/R trade not homeowners or those who aren’t properly certified. HVAC school covers the basics of how an air conditioning and refrigeration manifold works and how it is used. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school welcomes Chris Stevens from HVACR Videos to talk some refrigeration temperature controls basics. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Eric Mele is back on HVAC School Podcast. We go over some best practices and tips for performing a quality clean and check on small refrigeration systems. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school demonstrates how to calculate target superheat for fixed orifice metering device AC systems using testo Smart Probes and then how to measure superheat. Featuring Bryan Orr. Testo: https://www.testo.com/en/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school welcomes back Eric Mele. He goes through his tool bag and shows the tools he uses to work on small refrigeration units in the field. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school shows how to use the Testo Smart Probes app and Testo 605i's from the new expanded Testo Smart Probes case. We use the kit to calculate total system BTU removal during operation. Featuring Bryan Orr. Testo: https://www.testo.com/en/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school measures static pressure drop across an air filter using the Testo 510i from the new expanded Testo Smart Probes Case. Featuring Bryan Orr. Testo: https://www.testo.com/en/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

How does a vacuum pump work? When should you change the oil? What does that oil do anyway? We answer these questions and more in this episode of HVAC School Podcast. Featuring Kevan Mayer. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school shows how to calculate system capacity using enthalpy. We use the UEI hub kit and some simple calculations to do this. Featuring Bryan Orr. For more info on UAE instruments visit http://www.ueitest.com/ Carrier: https://www.carrier.com/carrier/en/us/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Warning! Sucking water into your leak detector is something you should never do! In the case that this does happen, we see how to get it out with the NAVAC NRP8DI Vacuum Pump. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school measures total A/C external air static pressure demonstrates using the Testo 510i manometer from the new expanded Testo Smart Probes case. Featuring Bryan Orr. Testo: https://www.testo.com/en/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC School Podcast is back for a short episode bringing you some key tips to new technicians. This time we cover HVAC/R service valves and caps. Hosted by Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school measures In Duct Airflow using Testo 405i from the new expanded Testo Smart Probes Case. We use the Testo smart probes hot wire anemometer and smart probes app to measure airflow inside the duct. Featuring Bryan Orr. Testo: https://www.testo.com/en/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school detects surface moisture using tools from the new expanded Testo Smart Probes Case. We show how you can use the Testo Smart Probes to detect surface dewpoint and prevent moisture issues before they start. Featuring Bryan Orr. Testo: https://www.testo.com/en/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school measures air velocity using Testo 410i from the new expanded Testo Smart Probes Case. We show how to use the volume flow outlet app in the Testo smart probes app to calculate air velocity and air volume flow. Featuring Bryan Orr. Testo: https://www.testo.com/en/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school podcast talks TXV / TEV bleed and non-bleed. Why does it matter to your compressor? Featuring Jamie Kitchen. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school reviews the new expanded Testo Smart Probes Case. We explore its the all the tools and their uses. Featuring Bryan Orr. Testo: https://www.testo.com/en/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC School welcomes back Jim Bergmann to share his know how on the MeasureQuick HVAC app. This training video has been streamed on the HVAC School FB page on 8/15/18. He covers: - Taking readings - Generating Reports - Benchmarking Systems - Non-Invasive testing - Fieldpiece, Testo and iManifold support Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC School discusses why both compressor and evaporator superheat matter. We also address why some common confusions and misconceptions related to each happen. Featuring Bryan Orr. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school podcast talks evacuation, conductance speed, microns, core removal, decay rate and all that other nerdy vacuum stuff. Featuring Jim Bergmann. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

HVAC school is back to demonstrate how to clean a condenser coil impacted with lint using Viper from Refrigeration Technologies. We show before and after results as well as every step in between. Featuring Jesse and Jayson. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/ Refrigeration Technologies: https://www.refrigtech.com/

In this video we review the Danfoss KPU19 Thermostat / Mechanical Temperature control and How it Works Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

This video is a companion to the water source podcasts with Eric Mele at HVACRschool.com. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Can you really freeze water in a vaccum by pulling down too fast? what should you do about it? Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

I upgrade an “A” series Carrier Infinity Controller (Thermostat) to the latest software step by step. Carrier: https://www.carrier.com/carrier/en/us/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this episode we talk w/ two techs recently out of tradeschool and get their perspective on their trade education and how it compares to the field Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

I woke up to an error on my Carrier Infinity system, this video shows how to diagnose an ECM motor 3.0 as well as some common things to look for on ECM motors. Variable Speed Motor Diagnosis with The Genteq TecInspect is also shown. Carrier: https://www.carrier.com/carrier/en/us/ Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Microchannel condensers and things to be aware of about their installation, service and cleaning. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this episode Eric dives into the world of pumps, controls, cooling towers and everything else related to the water side of a water source heating and cooling system Read all the tech tips, take the quizzes and find out handy calculators at https://www.hvacrschool.com/

Part 2 of the discussion with Trevor Matthews with Emerson about causes of air conditioning and refrigeration compressor failure and the causes Verifying System Operation Sheet from Emerson http://hvacrschool.com/EmersonVerify Diagnosing Compressor Failures from Emerson http://hvacrschool.com/CompFailuresWe talk with Trevor Matthews with Emerson about causes of air conditioning and refrigeration compressor failure and the causes Verifying System Operation Sheet from Emerson http://hvacrschool.com/EmersonVerify Diagnosing Compressor Failures from Emerson http://hvacrschool.com/CompFailures Read all the tech tips, take the quizzes and find out handy calculators at https://www.hvacrschool.com/

We talk with Trevor Matthews with Emerson about causes of air conditioning and refrigeration compressor failure and the causes Verifying System Operation Sheet from Emerson http://hvacrschool.com/EmersonVerify Diagnosing Compressor Failures from Emerson http://hvacrschool.com/CompFailures Read all the tech tips, take the quizzes and find out handy calculators at https://www.hvacrschool.com/

My own Carrier Infinity system has had an issue intermittently with communication loss after storms and power outages. I show you a fix that has been recommended to me by many techs to use spare control conductors as a sort of shield. Read all the tech tips, take the quizzes and find out handy calculators at https://www.hvacrschool.com/ Carrier: https://www.carrier.com/carrier/en/us/ Mitsubishi Cooling & Heating: https://www.mitsubishicomfort.com/ Refrigeration Technologies: https://www.refrigtech.com/

We walk through some of the basics and most common symbols associated with reading an air conditioner wiring schematic or diagram. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/ Carrier: https://www.carrier.com/carrier/en/us/ Mitsubishi Cooling & Heating: https://www.mitsubishicomfort.com/ Refrigeration Technologies: https://www.refrigtech.com/

In this episode Bryan covers how to measure air velocity directly at a return or supply and what it tells you (edit : I say 405i when I mean 410i) Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

Eric Mele walks us through the components of water source heat pumps, how they work and what to look for Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

In this episode we speak with founder of Refrigeration Technologies John Pastorello all about chemicals and cleaners and how to best clean a coil Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/

I cover testing capacitors while running VS. Bench testing and which method we use for testing capacitors in which situation. All about how to test capacitors. Read all the tech tips, take the quizzes and find our handy calculators at https://www.hvacrschool.com/