Compressor will only fill tank once / air leaking out

by Michael Accardi
(Henderson, NV)

I have a Craftsman oiless 60 gallon compressor with issues. If the compressor is empty, the motor will turn on and start filling the tank. However, the regulator has some type of valve on the side that lets air out. The regulator is set to start at 140 psi and stop at 160 psi. The compressor will reach 160 psi and shut off, however, the little air valve on the side of the compressor keeps leeking air until the tank pressure reduces to 140 psi. Once the tank is at 140 psi the air stops leaking from the regulator, the motor tries to restart, makes a humming noise, and blows the breaker. I removed the cover over the pump and can hear an air leak from the what I believe is the high pressure side piston. I also try to manually move the wheel to cylcle the pistons, however it won't move. Once the tank is back to 0 psi I reset the breaker, the motor starts right up and the compressor once again fills to 160 psi, however, the problems I mentioned above start all over.

I replaced the regulator and both head gaskets. I don't know what else to do. The craftsman manual specifies certain torque for the screws that hold the heads onto the pump. I don't have a torque wrench so I just tightned the screws down good. Could I have tightened to hard and blown the head gasket again? Any ideas would help I'm getting very frustrated. Thanks in advance for any help you can offer!

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Bill says...

Hi Michael. You may have a number of problems, or just one that is manifesting itself in various ways.

So, lets get the obvious out of the way.

When the motor is off, the small valve that is leaking is, I believe, your unloader valve. When the motor stops on high pressure cut out, this valve opens to allow pressure over the piston to relieve, making restart within the power parameters of the motor and circuit.

If air continues to come out, you likely have a check valve leak. Go to the Valve page, and click the Check Valve link, read the page, and make sure first that your check valve isn't the problem.

If it was leaking and it solves your problem... good! If ensuring that the check valve is not leaking doesn't, post a comment on this thread telling me what you found and we'll move on to the next step. Make sure you add it to this thread so I can go back and review.

Cheers,

Bill






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Compressor will only fill tank once / air leaking out

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Nov 02, 2010
 It's fixed
by: Anonymous

Bill, thanks for your reply and having this excellent website as a resource for the public. I think I was a little premature on posting the question since after I posted it I dug around a little more on your website and found a great deal of information that helped me solve the problem.

Basically, when I changed out the head gaskets I noticed that one of the head gaskets was missing a little piece. The last part of the compressor that I checked was the check valve. When I checked the check valve I found that the little piece of head gasket that was missing was lodged in the head valve and not allowing it to work properly. I removed the blockage in the check valve, reassembled everything, and the compressor works great now.

Thanks again for your help!!!!

Mike

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Glad to be of help.

B.

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