Ed Russell Posted November 1, 2019 Report Share Posted November 1, 2019 I have 2 rooftop duo-therm ac's with heat pumps. the living room ac was working fine then the compressor started shutting down and restarting for maybe 2 to 3 seconds each time and would cycle on and off. The fan stayed on throughout. It has been 90 with high humidity so I turned it off for the night. This morning when I tried to restart the ac it took about 2 - 2 1/2 minutes for the fan to come on (normal start) but again the compressor would try to start, I could here it bump on but shut back off, after a couple times of this I shut it off again waited a while and tried it again same results. I pulled the capacitor check it with an analog volt meter. it bounced to zero then back at each side, and it had no visual damage. Any Ideas?? Quote Link to comment Share on other sites More sharing options...
I'mdonewiththis forum Posted November 1, 2019 Report Share Posted November 1, 2019 First of all, Welcome! Sounds to me like your compressor is about dead. Something is failing inside the compressor and it is pulling way to much power to try to start. It probably shut down from the overload tripping and wouldn't restart due to current draw. I don't suppose you checked to see if you could put your hand on the compressor when it first acted up? It was probably quite hot....... Quote Link to comment Share on other sites More sharing options...
Ranger Smith Posted November 1, 2019 Report Share Posted November 1, 2019 It sounds like a bad capacitor. You can really only check if compressor is pulling too much with a clamp on amp meter. I would go and buy the cap for $15 to 20 bucks and try that. Quote Link to comment Share on other sites More sharing options...
Ed Russell Posted November 1, 2019 Author Report Share Posted November 1, 2019 No I didn't. I rest my thermostat checked the lines in the unit to see if clean.. My wife said that when she turned it on earlier it sounded like it started hard. is there anything further I can check? I did checked the 3 amp fuse,good, didn't see loose wires either.. Quote Link to comment Share on other sites More sharing options...
Ed Russell Posted November 1, 2019 Author Report Share Posted November 1, 2019 5 minutes ago, Ranger Smith said: It sounds like a bad capacitor. You can really only check if compressor is pulling too much with a clamp on amp meter. I would go and buy the cap for $15 to 20 bucks and try that. I need a 50+15 and have a local shop looking for one. I wasn't able to find one on amazon, Graingers. ebay,.. Was hoping I missed something on the board. Quote Link to comment Share on other sites More sharing options...
D&J Posted November 1, 2019 Report Share Posted November 1, 2019 1 hour ago, Ed Russell said: I have 2 rooftop duo-therm ac's with heat pumps. the living room ac was working fine then the compressor started shutting down and restarting for maybe 2 to 3 seconds each time and would cycle on and off. The fan stayed on throughout. It has been 90 with high humidity so I turned it off for the night. This morning when I tried to restart the ac it took about 2 - 2 1/2 minutes for the fan to come on (normal start) but again the compressor would try to start, I could here it bump on but shut back off, after a couple times of this I shut it off again waited a while and tried it again same results. I pulled the capacitor check it with an analog volt meter. it bounced to zero then back at each side, and it had no visual damage. Any Ideas?? Sounds like you tested the run cap, does it have a start cap and relay. It sounds like the start cap isn't kicking in. Denny Quote Link to comment Share on other sites More sharing options...
Ronbo Posted November 1, 2019 Report Share Posted November 1, 2019 You can try adding a hard start kit to your unit. I just ordered one today for $8 on amazon Quote Link to comment Share on other sites More sharing options...
Big Greg Posted November 1, 2019 Report Share Posted November 1, 2019 I have had this problem twice, the fan comes on and the compressor starts but stops in 3 or 4 seconds. I replaced the start capacitor and PTCR to fix the problem. You can purchase a kit from RV dealers or online for about $30. Greg Quote Link to comment Share on other sites More sharing options...
Ranger Smith Posted November 1, 2019 Report Share Posted November 1, 2019 6 hours ago, Ed Russell said: I need a 50+15 and have a local shop looking for one. I wasn't able to find one on amazon, Graingers. ebay,.. Was hoping I missed something on the board. 50 + 15 is an odd one. Who makes the AC unit. I usually just replace them with a 35/5 at 370 volts and that is fine. Quote Link to comment Share on other sites More sharing options...
D&J Posted November 1, 2019 Report Share Posted November 1, 2019 (edited) 13 hours ago, Ed Russell said: I need a 50+15 and have a local shop looking for one. I wasn't able to find one on amazon, Graingers. ebay,.. Was hoping I missed something on the board. That is the run cap for the compessor and fan, go back into the box and look for a single smaller cap that only has leads and that will be the start cap and check it. Denny Edited November 1, 2019 by D&J Quote Link to comment Share on other sites More sharing options...
Ed Russell Posted November 1, 2019 Author Report Share Posted November 1, 2019 7 hours ago, Ranger Smith said: 50 + 15 is an odd one. Who makes the AC unit. I usually just replace them with a 35/5 at 370 volts and that is fine. Duo Therm by Dometic. Quote Link to comment Share on other sites More sharing options...
Ed Russell Posted November 1, 2019 Author Report Share Posted November 1, 2019 thank you all for the advice, I'll let you know my results. Quote Link to comment Share on other sites More sharing options...
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