Tech Tips

If you went to school and learned the “gas laws” early on, you probably thought it seemed LAME. Then, later, things like mass flow rates, airflow conversions, and compression ratios seemed HARD. Well… It's because HVAC is hard if you don't understand the concepts behind the gas laws, even if you never learn to do […]

It should be stated and restated that codes and code enforcement vary from location to location within the US. The IMC (International Mechanical Code) is one of the most widely utilized and referenced. The 2015 version of the IMC section 307 is what I will be referring to in this article. Condensate Disposal  The code […]

This tech tip was a collaborative effort between Matt Bruner, Adam Mufich, Ed Janowiak, and Genry Garcia. Thank you to everybody who gave their input! The next time you come across a homeowner who wants a bigger HVAC system, or you simply want to set expectations for a customer, share this tech tip with them. […]

Introduction Replacing a reversing valve is either every technician’s dream or nightmare. The sheer amount of brazing involved in confined spaces will inspire either delight or nightmares about the upcoming valve replacement. Fortunately, these emotional highs and lows are uncommon because we don’t diagnose and replace bad reversing valves very often.  That itself poses a […]

This article was written by Don Gillis with Chemours. Thanks, Don! There are 3 main reasons we use “P” or “U” traps: Assisting in oil return to the compressor Preventing oil accumulation in the evaporator  Preventing liquid refrigerant or oil from entering the compressor while operating or during the off cycle Assisting in oil return […]

Let's talk about the magic that is inverters and how to test the boards that drive this technology. Inverters play an extremely important role in household appliances, industrial machinery, and the rising popularity of household HVAC systems. Inverters consist of a wide variety of electronic circuitry, and there are many situations in which they need […]

Think of it like this: It's a cold, wet, windy day. You can take an umbrella to protect you from the water alone, but that won't deal with the cold (temperature) or the wind (air convection). You can add in a light windbreaker, which will help keep the wind (convection) off. But if you also […]

It’s that time of year again—the furnace service calls are peaking. It’s a good idea to crack open Jason Obrzut’s book, Gas Heating: Furnaces, Boilers, Controls, Components, and listen to the many public podcasts and presentations by experts like Jim Bergmann. At HVAC School, we’re fortunate to have had some of the industry’s greatest minds […]

A few years ago, a friend of mine, Clive Mitchell, aka Big Clive, explained the Dunning-Kruger concept while he was a guest on my YouTube-based podcast, “HVAC Overtime.” Clive is another content creator on YouTube specializing in technical videos where he reverse-engineers electronic devices. Clive has a very analytical mind; he sees patterns in people […]