Compressor cuts in and out.

I have a 2.5 hp single phase belt driven compressor. It cuts in and out while building up to its required pressure. Thought that it must be the run capacitor so replaced both run and start capacitors. No luck so guessed it must be the pressure unit so replaced it but still no luck. (Bugga) Is it possibly a fault with the reset button unit and could I try bypassing it to see if that fixes it. Cheers Jeff.

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Jan 12, 2016
cut out n in
by: Doug in

That could be part of the reset button, but usually those go off and don't come back on their own. That is, you actually HAVE to push it back in.

More like likely it's a thermal cut-out with auto reset, which would be located somewhere inside the motor.

If you can somehow monitor the motor temp, you could probably determine if heat is the problem, and it does seem that's all that's left.

A model for the whole unit and especially the motor (if it's separate from the pump) might help, too, along with a description of any unusual noise it may be making while it start/stops.

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