HVAC School - For Techs, By Techs

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)....

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...

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...

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 workin...

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 goa...

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 r...

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 a...

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 ap...

Balancing complaints are common in the HVAC industry. In this short podcast, Bryan explains how diagnostic duct design solves those issues. "Diagnostic duct design" refers to using the duct system to locate and solve a customer's comfort problems. If a couple of rooms have problems with humidity control, then the duct system could be a culprit. However, before we even touch the ducts, we should lo...

Eric really likes ceiling cassette air handlers, so much so that he put them in his own home. We discuss ceiling cassettes vs. highwall and other ductless-related topics. A cassette air handler looks like a concentric fitting, and they are generally installed in acoustic or drop ceilings. Eric likes the comfort and easy installation. However, people who have low ceilings or dislike exposed equipme...

In this short podcast episode, Bryan breaks down the most common defense for bad practices: time in the industry. He also explains how to STOP USING IT as an excuse. When technicians communicate with each other, especially online, they tend to justify their practices with the phrase, "I've been doing this 30 years!" What they don't realize is that their old training (and habits) don't reflect the...

Devin Skipper comes on the podcast to give you an introduction to make-up air systems and explain their purpose. This time, we pull out all of the initials: MAU, MUA, DOAS, and MHGRV. Make-up air is outdoor air that we bring in to replace exhausted indoor air, usually in commercial systems. We use dedicated systems to bring in humidity-controlled air to rebalance the building to a positive pressur...

In this short podcast episode, Bryan covers multi-stage or variable-speed compressors. He also explains the impacts of staged compression. Multi-stage (or variable-capacity) compressors can come in many different forms, but they all have one thing in common: they can adjust their capacities. We typically rate equipment for its maximum capacity. However, when you vary the capacity, you get turn-up...

Jim Bergmann is back on the podcast to talk about the effects of dew point on coil TD. He also gives us a full rundown on recent MeasureQuick updates and what to expect in the future. When you see flags in MeasureQuick, those indicate symptoms of specific problems. MeasureQuick cannot outright diagnose equipment; it can only offer variables and educate the user based on the symptoms it notices. Re...

Bryan talks about EPR and CDS valves. We consider both to be evaporator pressure regulators, but they really function quite differently. CDS are Sporlan components that appear to be quite similar to evaporator pressure regulators (EPRs). EPRs go in the suction line and control the evaporator pressure. The pressure and temperature relate to each other, so the goal is to keep the evaporator from fre...

Jim talks about dew point, bubble point, and midpoint in refrigerant blends. He also covers the purpose of each and why MeasureQuick displays midpoint on the gauges. We've formerly used mostly pure refrigerants. However, as new refrigerant blends come on the scene, we have to deal with glide, which indicates that we have a range of boiling temperatures instead of a fixed boiling point. We have bub...

In this short podcast, Bryan discusses the ever-controversial topic of indoor temperature in the summer. The old "20-degree rule" has come up many times, and it's time to put it to rest. Not to be confused with the 20-degree delta T rule, the 20-degree rule basically states that the home A/C system can only maintain temperatures up to 20 degrees below the outdoor temperature. For example, if the a...

Nathan Orr is back. In this podcast, we discuss suction pressure in market refrigeration and how rack techs think about it differently than HVAC. On parallel rack systems, suction temperature helps technicians determine the cooling load and how to get that to temperature. You run your discharge air temperature a bit lower than the product temperature. Your suction pressure also lets you know if yo...

In this short podcast episode, Bryan explains why low static pressure may be bad. He also discusses the other indicators of airflow. When you look at fan charts, you'll notice that there will be an available static value. When you measure static pressure, you're looking for the pressure applied against the sides of the duct, not forward through the duct (velocity). Low static pressure is generally...

Nathan and Bryan have a rollicking conversation about Nathan's transition from residential HVAC to market refrigeration. Nathan also covers what he has learned along the way. Hopefully, his experiences can help you decide if moving to market refrigeration may work for you. Before Nathan went into market refrigeration, he handled problem customers and repeat issues on the residential HVAC side. He...

In this short podcast episode, Bryan covers pricing for HVAC/R parts and services; he explains how to come up with a fair price. To be able to price fairly, we need to understand what value and sacrifice look like. In the HVAC industry, we value hard work and growth in a way that some other people don't. We provide parts and labor and sell those in the free market, so we can control how much we ch...

We talk with chemical and cleaning expert Ray Field on Legionnaires' disease. We discuss what it is, its history, and what we can do to prevent it proactively. Cooling towers host all kinds of microorganisms, including harmful bacteria like Legionella. Legionella is a natural bacteria that you can find in bodies of freshwater, including lakes, but it was discovered relatively recently, in the 1970...

In this short podcast episode, Bryan covers ductless or mini-split cleaning. He collaborated with SpeedClean to map out this procedure and write a guide, which you can read  HERE . Cleaning is ultimately a maintenance procedure, so one of the main goals is to keep energy efficiency high (watts per BTU). You can test energy efficiency by using two psychrometers: one up top and one going into the va...

Andrew Greaves comes on the podcast to give us a sneak peek into the life of a tool manufacturer. Andrew has worked in the field for a long time and has recently begun working for NAVAC. He currently works as a regional manager who oversees operations in 24 states; his main task is to establish a nationwide distribution network for NAVAC products. Andrew recognizes the need for communication betwe...

In this short podcast episode, Bryan covers the bypass factor in airflow and psychrometrics. He also explains why it matters to techs. The bypass factor is a ratio: you take the difference between the evaporator coil temperature and outlet air temperature as compared to the inlet. In other words, you find the difference between your TD and delta T. When air moves over the coil, only some of it con...