AC compressor won’t Cut Off

[joesmainship]

I usually run our bedroom AC at night in the LO Cool mode so the compressor will cycle on and off while the fan runs continuously. Last night, the compressor would not cut off. I turned thermostat to OFF, it still wouldn’t cut off. I finally turn it off via the AC breaker. The fan operates correctly. I let it sit for a few minutes and flipped the breaker back on and the compressor came back on with the thermostat in the OFF position. Anyone have an idea what the problem might be?

[TucsonJim]

Hi Joe - Can you provide the make and model number of the AC unit and thermostat?

Jim

[Jeff&Kam]

I do hvac for a living. The compressor start contactor is welded closed. Sometimes it will come undone if you let it sit. Otherwise you probably need a new contactor board.

[joesmainship]

Today was a travel day so I waited to see if the problem still existed at our new campground. As I powered it back up, the compressor started no matter what the thermostat setting. The unit is a Coleman Maxx-Air 15000 BTU unit. I suspect Jeff&Kam's diagnosis is correct. I have to go back in for some warranty work when I get back home, so I'll add this to the list. Love these units. They are so much quieter than the dometic units I had in my previous camper. This is the first problem I have had with them.

[CatherineThornton]

Hi
Sometimes it happens due to damage in compressor. Is the compressor is heating or making a sound? If the connection is loose or there is dust in compressor than it happens. It is better to check it by the service providers so that it may not lead to heavy loss.