HVAC School - For Techs, By Techs

In this episode, we talk with Jeff Nieman about chillers and how they work. For those of you who primarily work in residential or light commercial HVAC, chillers may be unfamiliar at best and terrifying at worst. However, centrifugal chillers' parts are actually quite similar to those of HVAC units. They have an evaporator, compressor, condenser, metering device, and control system, just like the...

In this episode, Bryan and Bert talk about properly stripping cables and leak detection best practices. Bert is a senior technician and self-proclaimed leak detection expert. As a slight aside, Bert CAN'T STAND when technicians strip wires. Basically, his advice is NOT to cut around the wires or use a razor knife. Leak detection starts when you walk up to a unit and confirm that the unit is low on...

n this episode, Bryan covers evacuation, recovery, and dehydration. Evacuation refers to putting a vacuum pump on the system and pulling it down. We use a few different measures of vacuum, including inches of mercury ("Hg) or microns (millionths of a meter of mercury). We use such small units to measure a vacuum that effectively boils off moisture in the system. You must pull the vacuum very  clos...

In this episode, Bryan talks to Business and Sales Trainer Bob Gee about HVAC business practices. Bob has watched sales and leadership evolve a lot over the years. Today, success in sales depends on your abilities to build relationships with the customers. You're no longer "selling" things; you are "helping people buy" things. Instead of pushing products to people, it's best to "ask your way into...

In this episode, Bryan talks to YouTube star Stephen Rardon about combustion analysis. In Florida, we mostly have A/C units and heat pumps. High-efficiency furnaces are not in our wheelhouse, but furnaces are more like A/C units than you would imagine. Stephen Rardon makes some excellent comparisons between the two. For example, you can get an idea of how an A/C system is running without checking...

In this unedited episode of HVAC School, Bryan and Nathan talk about some basic rules for circuit board diagnosis. So, circuit boards are boards with circuits in them. They come in two types. The traditional printed variety contains switches, relays, and resistors. The other type contains silicon chips and uses logic and processing inside the boards. You may notice these in some high-end commercia...

Benoit Mongeau comes on the podcast to talk about high-efficiency gas furnace basics and maintenance practices.  When maintaining a high-efficiency gas furnace, you typically don't have to worry about cleanliness in the same way you'd worry about an oil furnace. However, condensate drains need regular cleaning. You'll want to look for cracked heat exchangers and pay attention to your manifold gas...

In this episode of HVAC School, Bryan talks with Ulises Palacios about some cool technology. Ulises has become a technology expert through his many years of working with new tools. He has recently been involved in testing new technologies, and he has worked with Jim Bergmann. Cutting open a compressor is one of the most useful diagnostic tools you can use on a failed compressor. It is also an exce...

In this episode of HVAC School, Bryan covers the basics of heat pumps. Heat pumps are common technologies in Florida. They reverse the sequence of the typical refrigerant circuit: the indoor coil can become the condenser, and the outdoor coil can become the evaporator. Heat pumps can achieve that transition via a reversing valve, which changes the directions of the suction and discharge lines. The...

In this episode, Bryan and Nathan have a banter-filled conversation about electrical components that confuse techs. If you are looking for a serious educational episode, we suggest you look elsewhere. Low-voltage circuits may confuse the new technician because the "common" terminology is far too common in the circuit. (See how confusing it sounds in everyday use? We don't have to say "common this,...

This podcast is a high voltage A/C electrical class that Bryan gave to some of the Kalos apprentices. The high voltage journey begins with basic electrical theory. Basically, a difference in charge is needed for electrons to move and generate power. Motors, which are inductive loads, are the greatest users of power that we will encounter in the field. Inductive loads generate magnetism and utilize...

In this episode, Bryan talks to Justin Skinner about the standard gas furnace sequence of operation. Regardless of the furnace type, it all begins with a heat call on W... Then, the furnace checks the safeties to make sure ignition is possible and safe. If all systems are a go, the inducer motor comes on and clears a path for the exhaust. The furnace then proves that the path for the flue is clear...

Central Florida techs know the Southern winter all too well. Let's face it. It doesn't get super cold here regularly, but when it does, EVERYONE FREAKS. We get an abundance of service calls for unpleasant but not truly problematic conditions when people use their heaters. When people first turn on their heat, they can get a nasty surprise: a horrible dirty-sock smell and sometimes a shrieking smok...

In this episode of the HVAC School Podcast, Bryan talks with Jeremy Smith about refrigeration tips, terms and processes. They also cover the similarities and differences between A/C and refrigeration. Being on-call as an A/C tech is not all that different from being on-call as a refrigeration tech. Similarly, the principles of heat transfer don't change between the A/C and refrigeration trades. Bo...

In this episode of the HVAC School Podcast, Bryan talks with Tim Bagnall about flowing nitrogen. Many techs  don't  flow nitrogen. Some may say that it is overkill, but it has been shown that flowing nitrogen displaces oxygen while brazing and prevents harmful scale from forming on the copper. Scale is very problematic, and it will likely ruin your copper lines if you keep those lines open to air....

In this episode, Bryan goes back over the basics and stresses the importance of diagnosing the whole system . I'll cut to the chase: inspection is NOT overrated. Inspections help you become more familiar with HVAC systems and can help you catch on to minor issues before they spiral out of control. Check air filters, check the charge, check the evaporator coil... does the inspection checklist ever...

In this podcast episode, Bryan goes over best practices for diagnosing and replacing an A/C or refrigeration compressor.  When testing for a shorted compressor, make sure the compressor is isolated from all of its circuitry. You would see low ohms to ground in a shorted compressor. Do NOT measure from winding to winding or terminal to terminal to diagnose a short. You may also come across an open...

In this episode of HVAC School, Bryan covers the "5 pillars of refrigerant circuit diagnosis" and why they matter. They are: Superheat Subcool Suction pressure Head pressure Air temp split (delta T) These 5 readings give you a holistic idea of the A/C system. Instead of getting hooked on checking only superheat and subcool all the time and dismissing potential diagnoses, you can use these five rea...

In this episode of HVAC School, Bryan talks to his sons about basic electrical theory. Electrical theory normally requires trigonometry, calculus, and all of those fun maths. However, the basics are so easy that a 12 and 14-year old can figure it out. Electrical theory follows many of the same principles as thermodynamics—however, electrical theory concerns charges rather than heat. Conductors and...

This episode of HVAC School is a Kalos meeting where Bryan talks to his team about an incident where a leak was erroneously detected on the evaporator coil. The system was three months old, and one of our junior techs diagnosed a leak on the evaporator coil. (What?? That never happens!) So, the customer was quoted for a new evaporator coil. One week later, the charge was low again. The junior tech...

In this episode of HVAC School, we discuss the entire basic refrigerant/compression 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...

In this episode of HVAC School, I talk with my 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...

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...

In this episode of HVAC School, Bryan talks to Leslie about the deceptive TXV. 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 al...