Tech Tips

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 […]

Relays can be used for many different control applications, including controlling fans, blowers, other relays, or contactors, valves, dampers, pumps, and much more. A 90-340 is a very common, versatile relay that many techs have on their truck. So, we will use it as an example. A relay is just a remotely controlled switch that […]

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. […]

In HVAC, you will hear the word “flux” used in two totally different parts of the trade. You may have heard of magnetic flux before. Magnetic flux is the lines of force that emanate from a magnet. You often hear about magnetic flux lines in discussions of motor theory. Transformers also use electromagnetic flux to […]

So, I hear you’re just finishing trade school. Well done. You chose to take an excellent path, and now your journey is just beginning. How this will go is really up to you, and that’s a good thing! You aren’t going to be forced in one direction or another; you get to choose. Let’s talk […]

My technician (and brother-in-law), Bert, made a good point. (It’s hard for me to admit it, but it’s true.) When he needs to open the refrigerant circuit to make a repair, regardless of whether he is recovering or pumping down, he pulls out his nitrogen tank and his regulator. (We like the Western Enterprises VN-500 […]