Will not re-start

by Mike
(Somerdale NJ)

Have a Thomas Ultra Air Pac,4 gallon...I have been all over this site and all indicators point to the pressure switch.This will not re start once it comes back down to low pressure,but if I crack the line from the top on compressor(no air comes out from line,so check valve is working???)..the unit starts back up with no problem,..is it in fact the pressure switch,or is the motor too weak for re start???If I shut off the pressure switch manually,say at 40 lbs,and the try to re start ,again the motor just struggles then trips breaker,again if I crack line at cmpressor head,it will restart. Unit is only a few years old,with minimal use.
Thanks in advance for any input

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Bill says...

The issue seems to be one of load, Mike. Cracking the line dumps any air pressure over the piston, and without that load, your compressor starts. Put the load back on, and it won't start and pops the breaker.

I'm thinking that it's an unloader valve that isn't dumping air at high pressure cut out, a weak or failing start capacitor, or a weak or failing motor.

Cheers,

Bill