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A/C compressor tries to start just keeps cycling


Ed Russell

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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??

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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.......

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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. 

Steve and Joy

Amateur Radio Operator WZ1T . . .  Flex 6600 M,  Flex PGXL, Flex TGXL, 

2014 Itasca Suncruiser 38Q . . . Lincoln MKX Toad


The Kids . . . Yogi the Yorkie  passed 10/20/2018. . . Cookie the Chihuahua passed 11/30/2017 . . . Cooper the Aussie Doodle passed 3/10/2020

Abbie  and Abel  the Doodles . . . Brother and Sister Born 02/02/2020   . . . Lucy the Yorkie . . . and Axel  . . .The Bernie Doodle

 

Where We Are Now

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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.

 

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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 

Denny & Jami SKP#90175
Most Timing with Mac our Scottie, RIP Jasper our Westie
2013 F350 SC DRW 6.2 V8 4.30 Gears
2003 HH Premier 35FKTG Home Base Nebraska

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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

Greg & Judy Bahnmiller
Class of 2007
2014 F350
2007 HitchHiker Champagne

Both sold 2/19, settled in Foley, AL after 12 years on the road

http://bahnmilleradventure.blogspot.com/

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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.

Steve and Joy

Amateur Radio Operator WZ1T . . .  Flex 6600 M,  Flex PGXL, Flex TGXL, 

2014 Itasca Suncruiser 38Q . . . Lincoln MKX Toad


The Kids . . . Yogi the Yorkie  passed 10/20/2018. . . Cookie the Chihuahua passed 11/30/2017 . . . Cooper the Aussie Doodle passed 3/10/2020

Abbie  and Abel  the Doodles . . . Brother and Sister Born 02/02/2020   . . . Lucy the Yorkie . . . and Axel  . . .The Bernie Doodle

 

Where We Are Now

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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 by D&J

Denny & Jami SKP#90175
Most Timing with Mac our Scottie, RIP Jasper our Westie
2013 F350 SC DRW 6.2 V8 4.30 Gears
2003 HH Premier 35FKTG Home Base Nebraska

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