Jim Wheeler 2017-09-06 05:37:30
Causes of early compressor failures Because I’m known as the air-conditioning guy, I get a lot of questions from consumers and friends, and some are (if you will excuse the archaic expression) real doozies. Here’s a recent example. The pastor of a local church told me about a situation he was dealing with where his building had two packaged A/C units that were less than five years old and they had both experienced compressor failures. Well, that was hard to believe unless they had been struck by lightning (they hadn’t). He also told me his contractor said the compressors were no longer under warranty (?). After I explained it to him, he now knows compressors on four-year-old units still are under warranty. Now, should packaged A/C units fail in the first five years of life? Absolutely not and two of them shouldn’t have failed at the same time. In fact, packaged systems that are properly maintained should easily run for 20 years or more if no one has damaged them and there are no electrical problems. But, a church is a commercial property and the units probably were supplied with 3-phase electricity, so a lot can go wrong. Losing power to one of the three incoming circuits or a voltage imbalance between them or a lot of electrical interference on a leg can cause a compressor to fail. And this is where a good, experienced commercial service tech with the right tools (such as a true RMS meter) will outshine residential service techs that are unfamiliar with 3-phase systems. But what worries me in this case is the servicing contractor (because of his “out of warranty” statement) doesn’t sound too reliable. I wonder whether his installing or servicing practices couldn’t have been responsible for the early system failures? Understand that packaged HVAC systems are a lot like window units (although they are designed much better) in that the refrigerant circuits are factory-evacuated and -charged so there is no reason for a technician to ever hook up his/her gauges for servicing unless something has failed. However, unlike window units, these systems do come with service ports and unfortunately that is too much of a temptation for many service techs. Many think they can improve the operation by adding (sometimes even the wrong) refrigerant. My recommendation on packaged units is the gauges should never be connected unless there has already been a system failure. However, after I suggested this in a training class a contractor asked me to put on for his service people a few years ago, the service manager stood up and told the group he would fire any man who didn’t connect his gauges on every maintenance operation. I guess he thinks that might give a better impression. But every time gauges are connected to a system there is a greater probability of refrigerant leaks, introduction of contaminants and over-charging, all of which can result in early compressor failures. Just taking the temperature at critical locations with a good thermometer does the same job without the potential for damage. JIM WHEELER is an award-winning journalist who has worked in various positions in the HVACR industry since the early 1970s. His articles have been appearing every month since October 1986.
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