It started with a funny noise that was the rear bearing on the motor going out. There was just enough play in the shaft for the fan to nick the shroud on occasion. Bought replacement motor. Wasn't exact replacement but I got it in. It wasn't running fast enough. That was the run capacitor. Easy fix (but try to find one on a weekend). Back in business for nearly a week now. Cool. Literally. Closed everything up on top. Job well done. Drank another beer.This morning. It's over 90 early. I turn it on. Compressor kicks in. I'm all proud of myself. Then the compressor kicks off 3 minutes after it turned on. I tried various things. Same story over and over. Right now it's running but every window is open and every fan is going. It must have turned back on briefly because I just heard it turn off and there was cool air for a few minutes. I was up top earlier and none of the pipes were hot or cold like they're supposed to be. When the compressor is on, they are.Any ideas? I'm nearing the limit of my knowledge. I had replaced motor, blower fan, and capacitor before. So this time wasn't too hard. But I was kind of hoping that was all that could go wrong. Apparently not. Could it have something to do with it being so hot? Right now is the hottest so far this year at 99.

Units low on freon will short cycle run for just a few minutes or less and shut off. Then repeat the cycle. Maybe that is what is going on with yours. If you replaced all those parts, it sounds like your unit had reached the end of its life and a total replacement might have been wiser.

I'll test the heat theory tonight. Right now it's just a hunch. My other hunch: when closing things up, I was moving around the other two capacitors quite a bit because the new one was a different shape and size. Maybe I damaged one of those (both originals and the big one doesn't look good). But I'm not even sure what they do. There are also a couple of relays. Electrical stuff really isn't my thing. I can fix almost anything if it's just a part replacement. But diagnosing this could be tricky for me. We're set up in a state park host site where there isn't a mobile RV repair business. If there was one, I would have probably called already.

It is definitely cycling a lot. It's almost like when you set the thermostat higher in the evening to maintain temperature until it gets cool enough outside to turn it off and open the windows.

Your heading is no compressor turning off. Then your story states it short cycles. You stated you have replaced the compressor. Thats amazing as RV roof top AC units, they do NOT supply replacement compressors. Coleman/Dometic/Carrier, NONE supply compressors and have not for almost 25 years. Now, RV roof AC units do not have pressure switches to short Cycle the Compressor when "low" freon. So, forget that post. Your unit does not run long enough to freeze, which could cause short cycling IF YOU HAVE A FREEZE SENSOR. You do not list Year/Model of RV and Model/Brand of AC unit and if you have wall tstat or roof top AC controls. So, once you give us this info we can give you more help. Doug

I looked. I don't think I accidently said I replaced the compressor. What I replaced was a faulty capacitor. Good to know it's not Freon or whatever they use. And no, it's not icing up. It never has. I just realized that the compressor has been running now over 20 minutes. I'm afraid to close up though because every time I did it earlier today after getting the compressor going again, it turned off within a minute. That said, it's not been on that long once today. Stupid phobia. I'll try closing up. See what happens.It's a Coleman on a 2006 5th wheel. We're original owners and I've done all repairs on it except on big one that the factory caused and fixed.

AC problem from hell: Now compressor is turning off.

Cheapfix
Explorer
Jul 28, 2020
I looked. I don't think I accidently said I replaced the compressor. What I replaced was a faulty capacitor. Good to know it's not Freon or whatever they use. And no, it's not icing up. It never has.

I just realized that the compressor has been running now over 20 minutes. I'm afraid to close up though because every time I did it earlier today after getting the compressor going again, it turned off within a minute. That said, it's not been on that long once today. Stupid phobia. I'll try closing up. See what happens.

It's a Coleman on a 2006 5th wheel. We're original owners and I've done all repairs on it except on big one that the factory caused and fixed.
dougrainer
Nomad
Jul 28, 2020
Your heading is no compressor turning off. Then your story states it short cycles. You stated you have replaced the compressor. Thats amazing as RV roof top AC units, they do NOT supply replacement compressors. Coleman/Dometic/Carrier, NONE supply compressors and have not for almost 25 years. Now, RV roof AC units do not have pressure switches to short Cycle the Compressor when "low" freon. So, forget that post. Your unit does not run long enough to freeze, which could cause short cycling IF YOU HAVE A FREEZE SENSOR. You do not list Year/Model of RV and Model/Brand of AC unit and if you have wall tstat or roof top AC controls. So, once you give us this info we can give you more help. Doug
Cheapfix
Explorer
Jul 28, 2020
It is definitely cycling a lot. It's almost like when you set the thermostat higher in the evening to maintain temperature until it gets cool enough outside to turn it off and open the windows.
Cheapfix
Explorer
Jul 28, 2020
I'll test the heat theory tonight. Right now it's just a hunch. My other hunch: when closing things up, I was moving around the other two capacitors quite a bit because the new one was a different shape and size. Maybe I damaged one of those (both originals and the big one doesn't look good). But I'm not even sure what they do. There are also a couple of relays. Electrical stuff really isn't my thing. I can fix almost anything if it's just a part replacement. But diagnosing this could be tricky for me. We're set up in a state park host site where there isn't a mobile RV repair business. If there was one, I would have probably called already.
DownTheAvenue
Explorer
Jul 28, 2020
Units low on freon will short cycle run for just a few minutes or less and shut off. Then repeat the cycle. Maybe that is what is going on with yours. If you replaced all those parts, it sounds like your unit had reached the end of its life and a total replacement might have been wiser.

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AC problem from hell: Now compressor is turning off.

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