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OK settle in this may be a long one. . . So I started popping breakers about a month ago on a water cooled system. It is on a boat but that should matter. It only popper the breaker after it had been running and met the t-stat temp and shut off, when there was a call after that it would pop the breaker. I tested everything and it looked good. I thought I had a pot-relay going out and I would replace it when it stop working completely. ( or when I had the time) It kept getting worse and worse so I changed it and it started popping every time. Test compressor and it was reading Mega ohms to ground. It was not a dead short, but was reading some. I replaced the compressor and filter, pulled it down to 500 microns, and everything worked great for 2 days. I left the boat came back the next weekend and the heat didn't work. Threw my gauges on it discovered it was out of freon. grabbed the testo leak detector and found the schader valve core was loose. Replace core, fill with R-22, everything worked perfect . . . until the first time the temp met the t-stat setting. When the temp dropped to 68 it tried to start and popped the breaker. I reset the breaker it starts fine and will run for years as long as it doesn't meet the t-stat temp and shut off. It is doing the same thing that it was doing before. So now I have a new pot-relay new run and start cap new compresor and stil doing the same thing. So I scared Im going to screw up a brand new compressor. The only thing I can thing of is this does not have a crank case heater. could I be getting liquid in the bottom of the compressor durring off cycles? I am beating my head thing what else it could be, and I cant think of anything.

Thanks for the help
 

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Just a guess , never even seen a boat A/C .

But it sounds like maybe it is trying to start against high head pressure ?

Try a time delay relay in series with the 24 VAC contactor coil / thermostat circuit ?

https://www.johnstonesupply.com/storefront/product-view.ep?pID=B11-835

Set for about 5 - 7 minutes .

God bless
Wyr

PS Is there a pump for condensing water ? If so , are you sure it or its controls are OK ?
 

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Did you also replace the potential/start relay? It may not be working.
 

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This is very intrusting or just some buboo...
see if you can provide following info
1. Do you have high pressure switch in the system
2. Supply water temp at comp off cycle and On cycle?
3. High side refrigerant pressure at off cycle and on cycle?
4. Compressor rated Amp?
5. Compressor Normal running Amp?
6. Compressor Hot pull Amp?

If I know all of this answers probably we can narrow down the problem
 
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