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blakeb's avatar
blakeb
Explorer
Feb 05, 2018

AC unit humming when I turn off the system.

I have a Dometic brand AC unit with a analog thermostat. When I turn the thermostat to off there is a humming noise coming from the AC unit on the roof. The only way it stops is to flip the breaker. The AC still works and blows cold. From what I gathered online it seems that the thermostat is not working properly to shut of the condenser and I should replace it with a digital thermostat. I was thinking that would be a cheap fix. I asked a RV repair shop in the area and they said there is something I would have to change on the AC unit itself to make the digital thermostat compatible. The kept going on about a circuit board and a thermostat (Same thing?) and both would need to be replaced for the tune of $250. Is there any truth to this? Shouldn't I just be able to get a cheap thermostat from Walmart that runs on batteries?
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  • DutchmenSport's avatar
    DutchmenSport
    Explorer
    Feb 05, 2018
    blakeb wrote:
    ...Shouldn't I just be able to get a cheap thermostat from Walmart that runs on batteries?


    I really do not have an answer regarding the electronics behind the air conditioner. But to respond to his question ^^^^. Why not go ahead and get a "cheap" thermostat and try it. Nothing lost except a small bit of $$$ if it doesn't work. And if it does, ... well then ... you've saved yourself $250, minus the cost of the thermostat.

    Try it, see what happens.

    I think, if you were to unwire the thermostat the humming should shut off. If it doesn't, then there's more going on than just the thermostat.

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