Question about Carrier 38CKC042 Air Conditioner

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My digital thermostat has shut off after a power failure. There is absolutley no display appearing. I pulled the thermostat off thinking maybe the batteries were no longer working but came to find out that the thermostat does not have batteries. I then went and bought a brand new thermostat that does have batteries for the display but when I properly installed the new one, the display worked (of course because of the batteries) but niether the heater nor the airconditioner comes on when I tried to set the temperature to have it come on. I also tried the Fan On option and the Fan won't even come on. Of course before I went and bought the new thermostat I checked the breaker to the AC and turned it off for a few minutes but that didn't help and I also looked next to the actual unit outside and did find a box attached to the house and thought that should be the individual breaker for the unit but when I opened the box there was no lever to trip inside or on the side of the box, just a wierd looking black hook looking think that had ON, OFF on it.The only thing I could do with that is pull it straight out toward me and I turned it aroung in my hand and inside of it was like some metal prongs that locked it in from where I Pulled it out from. What else can I do or can you please tell me where I can find something I should trip (like a breaker) on the actual AC unit. HELP! Any suggestions? I am not sure of the unit model number because I am at work. I just picked on from the list. The unit is only 4 years old

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  • roycasipit Oct 01, 2008

    I have the same problem. But now, my problem is locating the inside unit. Normally, how big is it? I opened up an air filter upstairs just to see if there's a way to access it but everything is completely walled up and sealed.


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What you have is a 24v control circuit problem. There is a transformer in the air handler ( inside unit ) you will have 220v on the one side and 24v on the other. If you have 24v from transform there is a small fuse on the pc board that could blow during power problems. On the inside cover you should find a wiring diagram.

Posted on Oct 01, 2008

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