My compressor is never turned off and this has happened to me more than
once. Mine has run long enough to where the run capacitater have burned up
on the motor so as to kick out the circuit breaker. Your problem is your
electric start/stop regulator. There are two sets of copper points in there
and every time they open or close there is an arc. After to many arcs those
points finally start sticking. The only cure is to replace the regulator.
Once it starts sticking it can't be trusted as it will progressively start
doing it more often. That regulator costs around 30.00 at
http://www.mastertoolrepair.com/ They have all that you need for all
compressors. They have that overload valve also but I doubt you need it as
mine does the same as yours when I pull it open to test, it won't kick back
in until there is very low pressure in the tank. I thought it was bad and
replaced it ( about 20.00 ) and the new one did the exact same thing. I've
replaced that relay 3 times over the last ten years, most in the last four
years as I now have little leaks here and there and the compressor has to
refill the tank much more often.
Dick

--
Richard H. Neighbors
Building and repairing fine billiard cues for real pool players at
affordable prices.
Over 35 years exp. Located in Cincinnati OH
ph.# 513 233-7499
e-mail
web site http://www.dickiecues.com
"Dave, I can't do that" wrote in message
oups.com...
So, where does your air escape from?

I am not sure. By the time I had unplugged it and dragged it out from
under the lathe, it had reset. I was able to feel that it was coming
from around the switch box. I turned it back on but it operated
normally. Hindsight being what it is, I should have dragged it out
before unplugging. sigh

I'm with you about the valve. I have just checked CH troubleshooting
guide on their site and it suggests the check valve needs replacing. I
can't find my model number there so have left a message to see what's
what. I bought this in about '98 so they may no longer support it for
parts. I'll be really ****ed off if that's the case.

vbg Sears HP I am guessing. I think I did a calc some time back and
it was about 2.5hp based on the Watts rating. Still a lot of power to
eat if it was running all night.

Where did you buy the new check valve? I might just do that if CH no
longer support this model. The unloader worked fine when I switched it
back on and but very unlikely it was the cause.

Dave