PROBLEM WITH DOMETIC RV ROOFTOP AIR conditioner

Bad run capacitor or bad compressor. If you hear an occasional click from the compressor try a new run cap and then a hard start kit. Otherwise it's more economical to purchase a new unit.

Hi,
No this sounds like a bad compressor....a bad capacitor would just be hard starting, not kicking the breaker after running..

heatman101

Hi,
Sounds like the compressor is toast...if the caps have been changed and there is voltage there, you have done all you can...replace the compressor or buy new...

heatman101

It sounds like your unit may have a bad run capacitor or start capacitor and relay. Low voltage will also cause this problem. First you need to make sure that you have the full rated voltages at the unit, if you do, then, have the run and start capacitors checked out and the start relay.

You need to check the capacitor for the compressor. If that's ok then us an ohmmeter to check the windings in the compressor. If the capacitor looks swollen then it is probably bad, otherwise you will need a multimeter with the capacitor check function. Let me know what you find.

You need to borrow a clamp on style amp gauge, and check amp draw on black wire in box where hydro wires connect. (PLEASE, be careful, and if not experienced in this type of test, don't try it, due to likelihood of getting a shock. ) If it's the compressor kicking in that's causing the breaker to trip, and capacitor is good, then it's usually a problem with either low incoming (supply) 110-120 AC voltage, which will cause high amperage draw, or compressor on it's way out causing high amp draw. If it's only drawing 15-18 amps, and your tripping a 20 amp breaker, then breaker is getting weak.

I would remove the lid from the compressor and verify the connections are all in place and not rusted or melted, More then likely your capacitor has gone bad for your compressor, unless you have the proper testing meter then Id recommend replacing the capacitor, and just check for any loose or burnt wires.
Take it with you to a local Hvac supplier to get a proper replacement.

Good Luck!

I’m happy to help further over the phone at https://www.6ya.com/expert/michael_341f3f9dee622e54

Try replaceing the start or run capacitor to the compressor. If no help you can install a start assist capacitor, it helps to start a tight compressor.

If you can hear compressor try to start, then kick out, then I'd say capacitor needs replace, but if you don't hear anything (moan or groan) from compressor, then I'd be looking at a new relay, or at least testing it.