Tech Tips

I need to warn you… The following list is the actual process we use at the company I own for our typical “standard” residential maintenance. I'm sure you will find some things you do differently. Take it for what it is, and I'm happy to get any feedback you may have. Read the call notes, […]

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.  […]

I am in the midst of testing the accuracy and repeatability of different types of airflow measurements for techs in search of the most practical methods for different applications. A commonly taught method for measuring airflow is the temperature rise method, where you use a heat source that produces a set number of BTU/h, such […]

It's Friday at 6 PM. The schedule is clear, as far as you can tell. Other guys have been getting cleared right and left, so you call in standby. Five minutes pass. Ten minutes pass. You check in again, and sure as &%$#, there it is! You get sent across town to another call that […]

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 […]

Receivers, which we sometimes call “liquid receivers,” are components that store refrigerant. You'll see it on everything from small self-contained refrigeration units to very large commercial and industrial systems. Many new techs who are used to residential air conditioning confuse receivers with accumulators. It's an understandable error, as they both contain liquid refrigerant. However, you'll […]

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 […]