compressor will not cycle
(Pleasant Hope, Missouri USA)
Compressor will not cycle - hums tries to turn over but cannot - blows a new 20 amp circuit breaker - I've had it to the compressor repair guys twice - first they replaced a pressure switch and sent it home as OK - bringing it home it pumped up fine (like always) then when I used some air and it tried to cycle, it just hummed and blew the breaker like it did with the original pressure switch. I disconnected the tubing to the check valve and found the check valve working fine - the new pressure switch includes a new unloader - I loosened the line from the the compressor to the unloader and the compressor runs fine untill I reconnect the unloader line. Any ideas? Could the unloader be out of adjustment? Am I lucky enough to have had a bad unloader replaced with a defective unloader? Any help is appreciated. Thank you.
Empty the tank. Will the compressor start? If so, let it run up to cut out pressure, and monitor the unloader valve to be sure it works.
wont restart after use
by chris fletcher
it wii fill up, but when I use it it will not start back up to keep air in tank,I had a problem with it before,it would filland then as i used it it would try to start but couldnt,and then blew reset, so I put a new preeure switch on it and it wont even try to restart
Chris, I suspect that it's not the pressure switch at all, but the unloader valve that isn't opening when the compressor reaches the cut out pressure level.
See the unloader valve page for more info. Then, empty the tank, hopefully the compressor will start, let it run up to cut out, and monitor the unloader to be sure it is working.
Unloader Valve may not be working
A friend of mine has a compressor he uses to run various tools and paint equipment. The compressor builds pressure Ok all the time most but every so often (at random) the compressor will bring the tank to prescribed pressure, shut off (with a hissing sound), and then when tank pressure decreases and switch calls for more air pressure the comprerssor tries to start but cannot.
Reading the unloader valve trouble shooting article it sounds like the unloader valve is possibly bad and only works sometimes. My friend states that he does not dare leave the compressor on for fear it will not re-start properly and burn up the motor (or worse yet start a fire) so he brings the tank to pressure, shuts down the compressor, and uses air until running out of pressure and starts the whole process over again.
Do you think the issue is with the unloader valve? Could an unloader valve fail intermitantly? or is there someting else we should check? Please let us know your thoughts.
Joe and Bill
Bill, I would dump the air, unplug the compressor, remove the unloader valve, clean it, replace it, and test it to see if it dumped the air over the piston on shut off for, say, 5 consecutive times. If it worked each time, I would suggest that the problem may be solved.
Or, the unloader valve was not the problem, I would be thinking along the lines of a start capacitor that is failing.
I would also check to see what else is trying to start or run at the same time as the air compressor, appliances that are on the same power circuit as the compressor. The compressor must have clean power for reliable starting and operation.
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I recently installed a u.s. General brand compressor and I'm having issues.
It runs great from an empty tank but can't start under pressure. The trapped pressure is never released from the compressor.
Manufacturer had me replace the check valve which did nothing. There is a small relief valve with a ring on the tank and the same relief valve coming right off the compressor. Not sure how this standard relief valve is supposed to act as an unloader valve?
Any help would be appreciated.
Well Kevin, I don't believe the check valve has anything to do with your compressor starting problem.
If you wander over to the troubleshooting section on the sitemap page, read the pages that describe what the unloader valve does, and then, check out to see if yours is working, will you?
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