HVAC School - For Techs, By Techs

In this short and nerdy science podcast, Bryan discusses how electromagnetism impacts every part of our lives. Electromagnetism refers to the movement of electrically charged particles. From transformers to the visible light that helps us see, the movement of electrons is a critical part of our lives. For example, light is an electromagnetic wave within the visible part of the spectrum. On the more complicated side, AC motors generate a rotating magnetic field, which generates electricity. Transformers can also step down or step up voltage via two electrical coils that transfer energy via magnetism; electricity moves on the other side. Electromagnetism deals in waves. The distance between these waves varies, and the space between each wave is called the frequency. Many radio stations nowadays rely on frequency for listeners to tune in, and you can fir several stations just between the values 88 and 108. With TV, you wouldn't even get a single channel in that range (88-108 is somewhere between channels 6 and 7 on the old VHF analog system). Frequency rates also dictate many properties of a wave. Radio waves and microwaves are on the low-frequency side of the electromagnetic spectrum, whereas ultraviolet and gamma rays are on the high-frequency side of the spectrum. Visible light is right in the middle, and frequency helps us determine which color we see. Waves move through a vacuum and can self-propagate, but old scientists believed that waves moved through a substance called the aether. Bryan also discusses: Hertz scale Electromagnetic vs. sound waves Electrons in chemistry and physics Atomic structure   Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this first live podcast episode, Bryan responds to audience questions and discusses moisture and humidity issues in HVAC. Moisture leads to other problems, including fungal growth. We often see moisture problems where the surface temperature meets the air dew point, not where hot meets cold. When the customer drives the temperature down too low, many surfaces in the home can meet the dew point and begin sweating, especially ductwork in unconditioned spaces and air handlers. When you increase airflow, you derate the HVAC system's dehumidification. That's because the evaporator coil can't get cold enough for moisture to condensate on top of it, meaning that the moisture stays in the air. If there isn't enough dehumidification, we may end up seeing a moisture problem. These problems are especially prominent on wood and finished surfaces and can damage those severely. When assessing a home, you also have to think about internal moisture gains, including from cooking, showering, and doing laundry. However, external moisture gains are a major concern from infiltration. Drawing poor-quality, unconditioned air from attics and the outdoors through cracks will increase those gains. You must also keep in mind that the dew point can be different throughout the house. Dew point will also be different on the ceiling compared to the floor. Some stratification occurs with height, so that can complicate matters and must be accounted for. Bryan also covers: Multi-stage compressors Dew point vs. relative humidity Infiltration, leakiness, and negative pressure The problem with bath fans Water in slab structures Boot sweating R-value and insulation in the attic Commercial buildings with fresh air requirements Condensate blowoff in horizontal installations Dealing with wet insulation   Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Eric Mele and Joe Shearer join Bryan to discuss the challenging issue of diagnosing and rectifying non-condensibles in the circuit. Non-condensibles are gases that don't condense, including nitrogen. These are NOT moisture or contaminants, and they can be tricky to diagnose; the pressure readings will likely be normal, but the charge will actually be quite low (around 60-75% of the usual charge). These gases also don't just enter the system suddenly in significant amounts; non-condensibles typically enter the system when lots of technicians work on it, or the gases have been there all along. One of the most telling symptoms of non-condensibles in the system is elevated head pressure and subcooling WITH flashing. (You can usually hear the flashing at the metering device if you listen.) Otherwise, the symptoms often mimic those of a metering device restriction, which is a much more common issue. The only real way to tell if you have non-condensibles is to weigh out the charge; you may recover the charge or pump down the system. When you come across a system with non-condensibles, the customer may merely notice decreased cooling performance for an extended period. However, when a system is allowed to run with non-condensibles for a long time, there will likely be some long-term effects on your system. For example, these gases can erode the needle on a TXV. Eric, Joe, and Bryan also discuss: Common misdiagnoses Metering device restrictions How metering device type affects non-condensible symptoms Liquid seals Pinching off the discharge line Copper plating on compressors Pumping down scroll compressors (and general pump down) Training other technicians to diagnose non-condensibles Liquid line and filter drier restrictions Long line sets and accessories   Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast episode, Bryan quickly covers defrost termination and failsafe. He also explains what they mean in refrigeration systems. We need to defrost evaporator coils anytime they drop below freezing (32°F, o°C). When evaporator coils have a coat of ice over them, they cannot transfer heat from the box to the refrigerant; the ice blocks the coil from the air in the box. In defrost, we add heat to the evaporator coil. We can add heat in the form of electric heat or hot gas (discharge gas); either of these can damage product if they run too long. A simple off-cycle defrost may also work on properly sized coolers and medium-temperature equipment. We can control defrost by fixing the cycle onto a timed schedule. Unless we can use a complicated algorithm with a series of sensors, we almost never initiate defrost based on temperature. Instead, we initiate defrost based on a timed cycle. The defrost termination relies on a thermostat or control to stop the defrost, so a defrost will end early based on a temperature reading (since it will be well above freezing). After the defrost ends, there may also be a dwell time where the coil can drain its moisture before the refrigerator starts cooling again; that way, the moisture won't freeze back onto the coil when the system starts operating again. If the defrost termination fails to kick in, we need to set a defrost end time to take the system out of defrost. We call that end time the failsafe. It is not a good idea to use the failsafe to predict the defrost cycles; it should only work in the case of emergencies. So, to sum things up, defrost termination relies on temperature, but failsafe relies on time.   Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

John Pastorello from Refrigeration Technologies joins us to talk about testing oil and refrigerant for contamination. He also explains what each test is good for. John developed the Checkmate testing kit when he recognized a need to test reclaimed and recycled R-12 for acid and moisture. The Checkmate method removed a small amount of refrigerant from the system for testing. The Checkmate apparatus hooks up to a refrigeration system to test the oil. You insert a tube with a rubber stopper, and you can draw refrigerant from the system when the tool pierces the rubber stopper; the method is similar to drawing blood. The kit then assesses the acid content in the refrigerant and creates a colored stain that indicates the acid content. You can use an included color chart to interpret the stain color. Checkmate also assesses oil based on its dielectric strength; contaminants can give oil conductive properties, which the test picks up on. Unfortunately, oil breakdown can happen even when technicians use best practices, and it's commonplace on aging systems. Some tests only pick up on acid, not moisture. However, Checkmate picks up on the moisture content as well, which can be an indicator of future acid problems. Many technicians don't perform oil testing frequently enough; if they test the refrigerant or oil at all, it's only infrequently, such as during PMs. More frequent testing could occur with easier testing methods, such as by using the Checkmate kit, and it could save HVAC system owners lots of money in the long run. John and Bryan also discuss: Diagnosing compressor burnout Conductive oil Gradual oil breakdown Schrader core testing devices PVE oil Air and moisture skewing other test methods Vapor testing Venting exemptions for acid/moisture testing (de minimis) Checkmate tube shelf life Suction driers   Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast episode, Bryan explains what to do when you get water in your tools. (Hint: the answer is NOT to panic!) Some technicians try not to get water in their tools at all. Depending on the climate and line of work, that may be an impossible task. In humid or coastal climates, you may deal with a lot of rain and moisture. If you work on cooling towers and boilers, you will be working with systems that rely on heat transfer through water, so you WILL encounter water. When your tools get wet, you can't just stick them back in your toolbag and pretend that nothing happened; the tools' performance WILL suffer if you don't address the issue. If your tools get water on them, they won't dry on their own; they will corrode. At Kalos, we use microfiber cloths to clean our hand tools after they get wet. In the case of battery-powered tools, make sure you remove the battery and dry it off as best as you can. Sometimes, you can use WD-40 to help displace water. You can also look into using degassing chambers to remove moisture from battery-free tools. These chambers look like crockpots and make it easy to pull a deep vacuum (below 500 microns) to remove moisture. (Don't put batteries or devices with refrigerant in the degassing chambers! Cell phones fall into this category, too!)   Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Mike Hardy from SpeedClean joins us to talk about how SpeedClean got started. He also explains why all contractors should consider engineered solutions. SpeedClean emerged from the need to make coil-cleaning a better experience. Mike's philosophy is to look at the "pain points" of common tasks so that his company can develop engineered solutions to reduce the issues of those "pain points." The goal of companies like SpeedClean is to make an HVAC job more efficient to boost technician productivity and provide good value. However, Mike also believes in consumer education to promote user adoption, and he wants to make sure he conveys the benefits of SpeedClean equipment. In the past, pressure washers were some of the only technologies available to clean coils well enough, but they often damaged the fins and led to unhappy customers. There also weren't many pump sprayers, and hoses weren't always long enough to reach the equipment. So, the CoilJet came into existence in 2007 and had a mostly positive reception on the US West Coast. Customer feedback helped Mike improve his product, and he continues to accept and integrate user feedback today. As mini-split systems began to emerge, a need to revolutionize indoor cleaning emerged. So, SpeedClean released the Mini-Split Bib Kit to make indoor ductless cleaning easy and mess-free. SpeedClean makes all of its products in the USA, and its company culture places a high amount of value on the employees and respects their life outside of work. There is an assembly-line-type methodology in place, and the company consistently meets demand. Mike and Bryan also discuss: Battery issues with the CoilJet Negotiating labor and product costs CoilShot evolution User adoption and "laggards" Systems thinking Cleaning efficiency best practices   Learn more about SpeedClean HERE. You can check out the HVAC School and SpeedClean mini-split cleaning guide HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Eric and Bryan talk through some non-standard ways of thinking about filter drier usage. They also discuss how to install these non-conventional filter drier ideas. The humble filter drier helps us prevent gunk from moving throughout the refrigeration circuit with the refrigerant. That way, you protect the compressor and metering devices. Ideally, Eric would install his liquid line filter driers right before the metering device, but that's not always practical. When you put a suction drier into a commercial refrigeration application, most people will want techs to remove it. Suction driers can drive up the compression ratio by creating a pressure drop, which is undesirable. However, Eric likes to leave the drier in the system if it won't impact the system efficiency too negatively. Replacing the suction drier is especially important in the case of compressor burnout or acid in the system. If you have an accumulator, it is best to replace it in the case of burnout; you will also want to install the suction drier near the compressor, which will help prevent or reduce accumulator damage in the case of burnout. Above all, when you add driers to the system, you want to put them in sensibly. Their goal is to protect the system, and their sizing and placement should help them do their job. Also, DO NOT put filter driers in the discharge line! (Yes, it happens.) Eric and Bryan also discuss: Lennox liquid line drier placement Factory driers Replaceable core driers Flares, ball valves, and bypasses Using check valves on heat pump systems Testing oil for acid and burnout Undersized filter driers Factoring material pricing into proposals and quotes Discharge mufflers vs. filter driers   Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast, Bryan discusses the recent ads and news articles claiming that homeowners are in trouble and that R22 is becoming illegal. The R22 phaseout has been on the agenda for a long time and will finally come into effect in 2020. HCFCs have ozone-depleting potential, and it is time to look at more eco-friendly alternatives, such as R410A and R407A. The phaseout has affected prices and will cease virgin refrigerant production. However, after the phaseout period begins, R22 will NOT become illegal; you will still be able to find it in supply houses for a while. Nevertheless, you will only have access to recovered stock, and the costs may go up as the supply depletes. It is also NOT illegal to recharge systems with R22 as long as the refrigerant charge is under 50 pounds. You also still cannot vent or import R22. Overall, the AHJ may make different rules, but the EPA is not making the refrigerant illegal. Customers need not worry about replacing their air conditioner. There may be benefits to replacing an air conditioner, such as efficiency gains. However, there is no legal reason for customers to worry about replacing their systems. As HVAC technicians, we should focus on repairing leaks on R22 systems for customers who do not want to replace their systems. The most important thing to do is be honest with the customer; you can ease their worries about the legality of their system. However, you can still be honest about the environmental impact if the customer expresses concern about that.   Check out The Engineering Mindset's YouTube channel HERE. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

My buddy Eric Kaiser from the ETS Group comes on to discuss a common problem we see in both students and techs as they study. We talk about issues with how they think about the trade and how to progress in it. Eric noticed that people who take classes or plan to get certified tend to study just for the end test. The tests may be industry-standard, but the students and technicians don't learn to apply their knowledge; they merely learn with the goal of passing the test. Many technicians look for courses to complete. Instead of absorbing information from articles and videos, people want their knowledge to be verified. As a society, we put so much value on completing academic programs. The truth is that learning is continuous; you don't suddenly need to stop learning once you complete a course, obtain certification, or pass a test. For schooling and study practices to be truly effective, the student or technician needs to have a mindset focused on applicable skills. In hiring, we should focus on the applicability of an applicant's skills. Instead of using a written test or relying on a resume, a physical assessment would be a much more useful hiring tool for HVAC/R job interviews. HVAC/R jobs have significantly more difficult physical "tests" than a mere certification exam: work ethic, working under pressure, solving problems, and applying best practices. Studying for an institutional test won't help technicians or students who want to get into the field. Eric and Bryan also discuss: Eating healthy on the job Certification tests Interest-driven homeschooling vs. test-driven public schooling Test-taking talent vs. applicable skills Communication and customer service skills Purging hoses and other best practices Society's overemphasis on degrees and certificates Benefits of traditional testing Willingness to learn   Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.