tomsem1 Posted February 8, 2012 Share Posted February 8, 2012 I have a compressor that is overheating, no cooling happening either. At first I thought it was just a problem with the thermal overload switch. I plugged in the compressor direct into wall outlet, and it would hum for about 5 seconds then a click sound from inside the compressor simultaneously with a little spark coming out of the overload switch and off for about 2 seconds, then on-again for 5 seconds and repeat. It would do this 7 second cycling forever, with no cooling in the evaporator, and compressor body just getting mildly warm to the touch. I thought it must be a bad thermal overload switch so I bypassed the switch to see what would happen (because the compressor was not hot at all, and overload switch should not have been activating). After I bypass the overload switch the cycling stopped, but now the compressor body getting really hot after about 4 minutes, and no cooling to the evaporator either. I measured 20 amps (!) in the power cord while this was plugged in. The only thing I can think of, in addition to a bad thermal overload switch, is maybe a bad starting capacitor. So maybe with a bad starting capacitor, there is 120VAC going to the motor running circuit, and just getting the motor hot. But no power going to the starting circuit in the motor. Does that make sense? Link to comment Share on other sites More sharing options...
Technivend Posted February 8, 2012 Share Posted February 8, 2012 These overload very rarely go bad. You probably have either a bad winding or a seized pump. The overload is working correctly as it is a bimetal overload that is getting hot due to the high current draw of the compressor. You shouldn't left it plugged in for 4 minutes without it starting as it could cause more damage. Before you start throwing electricity where it doesn't belong, dig out your VOM and get the resistance readings from the terminals on the compressor. Get the start-run, run-common, common-start and ground to each terminal. Post the reading back here once you get them. If you get ANY readings from ground to a terminal stop, your compressor is junk. AND never run the compressor without the overload. Link to comment Share on other sites More sharing options...
tomsem1 Posted February 9, 2012 Author Share Posted February 9, 2012 Good advice, I have blown a few electrical devices in my day. Here are the resistence numbers: common-start = 6.2 ohm start-run = 6.2 ohm run-common = .3 ohm ground-common = .2 ohm ground-start = 6.2 ohm ground-run = .2 ohm Link to comment Share on other sites More sharing options...
Technivend Posted February 9, 2012 Share Posted February 9, 2012 Pump is junk. You should have no readings to ground. Looks like one of the windings has shorted out inside. You should see numbers like 2 start to common, 6 run to common, 8 start to run with nothing to ground. These are rough numbers I am giving you so they are not in stone. Start to common plus run to common should equal start to run. Not only do you have resistance to ground but your circuit is shorted. Link to comment Share on other sites More sharing options...
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