Tech Tips

When I teach electrical basics, we do this exercise where we sit down and connect a 10-watt bulb to a power supply and through a switch. It’s a SUPER SIMPLE circuit—the kind you might have learned about in a high school science class. But then I grab another 10-watt bulb and tell them to connect […]

A lot of proper duct design comes down to an understanding of available static pressure and friction rate. We’ve covered this topic several times on this site and the podcast, but I wanted to focus on this ACCA chart specifically (shown above). If you want a deep dive, I highly recommend listening to my podcast […]

Every now and then, a tech will call me and give me the same story of woe. They’re working on a system and have the following readings: Low superheat Low suction pressure Low head pressure They’ll reassure me that the system airflow is correct. So, what could possibly be wrong? I’ll ask how they could […]

When I was younger, I used to play and watch golf quite often. My father enjoys golf, and he would take me with him on many of his Saturday morning rounds. As a kid, it was all about DISTANCE. All I cared about was how far I could whack the ball with a driver—ESPECIALLY when […]

This article about A2L refrigerants was written by Don Gillis with Chemours. Thanks, Don! HVACR service technicians find themselves at the forefront of the refrigerant transition in AC and commercial refrigeration. As hydrofluorocarbon (HFC) refrigerants with high-global warming potential (GWP) are being phased down, mildly flammable A2L refrigerants have been identified as potential lower-GWP alternatives.  […]

On an energized, intact circuit, you will read voltage across an OPEN switch when testing with a voltmeter. However, you probably won’t read significant voltage across a CLOSED switch. Both sides of a closed switch are electrically identical (or at least very close). Therefore, there should be no movement of electrons between the leads of […]

Just so you don’t get bored and quit reading, let’s get straight to the point. When the blower runs for more than a few minutes after the system has cycled off in cool mode, the air may continue to be “cooler” (lower sensible temperature) coming out of the supply. However, the heat content of the […]

I bought a crappy old house built in the 1920s a few years into my marriage. There were so many things wrong with it. Water intrusion, leaking pipes, roots in the sewer line… on and on. But it was our house, and we loved it. One issue was that the water heater was tiny, and […]

I’m a big dummy when it comes to my own air conditioning maintenance. I talk about the importance of changing air filters to customers and techs, but I never stay up on replacing my own. Yesterday, I walked into my mechanical room, and my 2-ton air handler sounded like a vacuum cleaner about to implode. […]