Question about Carrier 38CKC042 Air Conditioner

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Possible Contactor Issue

I have a 10 year old Carrier Heat Pump (Roof Top), sorry i do not have the model number available. Starting last night (7/23/09) I could tell the compressor was running, but no air was coming through the vents. I tried to turn off the unit at the thermostat, but the compressor kept running. The strange thing is I then bumped the temp setting down a couple of degrees and the blower then came on. I let it run at this setting a few minutes then bumped the thermostat setting back up to where it was, and evertything shut down. This whole thing repeated itself last night, and I had to do the same routine. At other times, the unit and blower turn on and off normally. It appears that when the room temperature is reached, the blower turns off but some times the compressor and fan do not. I am thinking a bad contactor, but I would think it would either be stuck open or closed. A dirty contactor maybe?

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Sounds like a bad fan switch in your unit. That unit has a fan board in it that is time delay on and off. Turn the fan to the on position and let it run all the time. If it keeps temp and does not shut off it is the fan realy board. The board also controls the compressor. Check that first and then the tsat. Russ

Posted on Jul 24, 2009


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