I’ve been wrestling with a heat/AC problem for about a week. I’ve got two split units, one for up, the other is for the downstairs. They are heat pumps and so the air handling units are indoors and the compressor is outside. The problem is with the production of heat in the upstairs unit: it didn’t/wouldn’t.
Between closing the unit down, resetting breakers, tripping/setting relay controls, pulling unit side fuses/breakers/disconnects, grounding circuit card test tabs, and knob-dicking the electronic thermostat I could get the SOB to work after an hour or so.
I couldn’t figure it out because the clues to what might be broke would change. : one time it would be the 50 amp breaker for the indoor component sometimes the 30 amp breaker for the outside, once it was both (several times it was neither). A couple of times it was shut down for faults that sensors in the outside unit detected and they’d throw a ‘blinking light code on two LEDs on the circuit card. Several time the card would indicate there was no power to the AC when there was.
It was a real pain and I was mulling over getting the AC guy out to take a look at it when I remembered the last time he came to look at my downstairs AC unit (about out two years ago): It cost me a fortune because it took so long to troubleshoot (he was good at ‘troubleshooting by replacement’) and the actual problem was that a relay had failed on the AC unit because the 50 Amp breaker for the heat unit was not well seated in the breaker box. The problem was not in either the indoor element or outdoor element, but rather with the breaker not being seated well. In short, if the power fails to the indoor air handling unit (like when the breaker burps) then it removes a needed signal to a relay in the outside unit that allows power to the fan/compressor to energize. If the breaker ‘chatters’ (as this one did because it was not well seated) it will eventually break the relay on the AC (even though the problem was not in/on the AC unit).
With that thought in mind I began to think I had a weak breaker and that it was tripping because of the heat strips that augment the heat pump were coming on. So yesterday PM I drove into Pulaski’s Home Depot grabbed a 20 dollar 50 amp breaker and solved all of my heat/AC problems. OBTW, I’ve concluded that the loud banging was the logical outcome from the outdoor compressor having power removed from it suddenly while under load.
George Santayana was right you know, those that forget the past are condemned to repeat it.