I have a Craftsman 1 HP compressor. It was working perfectly until it fell on it's side. I put it right side up and the motor wouldn't turn when the air pressure is below the refill threshold and it leaked at the unloader valve after it shut off from reaching max pressure.

I bought a brand new pressure switch with a new unloader. I hooked it all up and ran the compressor. When it shuts off at max pressure, air leaks out of the side of the unloader valve. Then it tries to start and it won't turn the motor. The unloader valve isn't working... here's a pic.

http://webhome.idirect.com/~mase1/comp3s.jpg

THe white arrow illustrates where the air is leaking out of...it's a hole in the side of the unloader valve.


I don't understand why this isn't working Should I plug the unloader valve hole with a set screw?

 

sphinx,

The unloader is likely doing what it's suppose to.
The unloader's job is to release the air pressure between the compressor head and the check valve.
It is leaking continuously because the check valve has malfunctioned.

Release the air pressure and take the check valve apart to see what is wrong with it.
It will be located at the tank where the air line from the compressor enters.

 

thanks for your reply Greg.... I removed the brass fitting that the compressor head line and unloader valve line attach too..there's nothing in there. The tank, compressor head, and unloader valve are fully "exposed" to each other... there's no "check valve". Could it have fallen into the tank?

 

sphinx,

The check valve is normally the fitting that is screwed into the tank where the line from the compressor attaches.
Does it look like there may have been a ball, seat and spring in the fitting?

 

hi
get some dish soap and squirt it on check it there not a crack on the thread part.

pg

 

Hey Greg.. the piece that I'm talking about is exactly the piece that you're describing..it's a brass fitting that screwed into the tank..attached to the compressor and the unloader valve...but there is definitely no provision for any check ball.. no sign of a seat...BUT there is a spring at the very bottom of the threads that go into the tank. I shook the tank around to ensure that there were no loose parts in it... nothing!

Here's a pic

http://webhome.idirect.com/~mase1/valve1s.jpg

 

sphinx,

Ya, I don't see much of that type and I forget how it is set up.
I might have an old one like that. If I get a chance I'll look to see how it works.

Regardless, it is broken and needs to be replaced.