Domestic Ac problem

[Lexman1968]

Ok we have a 2011 Heartland with a Dometic rooftop ac unit and its acting up. 1st off if you turn the unit on and move the slide on the a/c panel more than once to a desired temp it blows the circuit breaker. What I mean is if I turn it on the move it to 72 degrees and then to 74 degrees it will trip the breaker so we just set it and then turn it on. Now the new problem is I came back to the trailer with the a/c left on and it had tripped the breaker. I flipped the breaker on and it worked fine until I went to shut the unit off again. With the thermostat in the off position and the fan in the off position the Ac unit is still running but the fan portion is not. It sounds like the compressor is running but nothing else is. I turned the breaker off and it shut off then. The unit blows cold air though with the thermostat and fan on. Where do I start with this one? I know its under warranty but are there some checks I can do before finding a repair facility? P.S. The filter is pretty dirty so I pulled it down and ran the unit with out a filter and still acting the same.

 

[Bob&Patty]

Lexman. what fan speed are you running the A/C on?? Is there alot of humidity where you are??

 

[wdk450]

Lexman:
Some easy checks you can do on the breaker blowing problem is to disconnect shore power to the rig, then open up the circuit breaker box and tighten the screws making the connections to the AC wires. While you are there, why not check that all power wire connections are tight? You could also check the power connection inside the roof unit, I believe it is in a metal control box there. You should see the Romex power feed cable going into it. Bad connections can cause low voltage to the AC, which causes the AC to pull more current, and the breaker is a current limiting device.
Breakers can become weak from repeated tripping and trip too soon. Harbor Freight Tools has an inexpensive clamp on ammeter/DVM, which you can clamp around a power wire and read the amount of current flow. It will also read DC amperes if you want to check your battery charge/drain amperage.

 

[Lexman1968]

We are running it on both high and low settings. I can live with the twitchy thermostat but we literally can't shut the unit off without th breaker. The fan shuts off but the compressor still runs. I climbed up on the roof and pulled the cover off and had the wife turn it on. The unit is running properly from a cooling standpoint because when turned on the low side lines are cold to the touch and the high side line is hot to the touch. I think it's an electrical issue with either the thermostat or a circuit board not turning the unit off.

 

[wdk450]

This sounds like a problem with the control board in the AC, in the metal box on the inside I described before.

We are running it on both high and low settings. I can live with the twitchy thermostat but we literally can't shut the unit off without th breaker. The fan shuts off but the compressor still runs. I climbed up on the roof and pulled the cover off and had the wife turn it on. The unit is running properly from a cooling standpoint because when turned on the low side lines are cold to the touch and the high side line is hot to the touch. I think it's an electrical issue with either the thermostat or a circuit board not turning the unit off.

 

[Birchwood]

Mine never blew breakers but there was a situation where the compressor run but the
fan would not.Called Dometic and they seemed aware of this problem and shipped a new
control module to a nearby RV repair shop in Florida.Repaired under warranty with no
problems.
May the breakers are blowing to save your compressor from overheating!