Can anyone give me advice on why my garage air compressor won't shut off?

The compressor is a small 12 gallon 1hp unit from sears. I have hardly used it at all and the warranty just expired. The problem is that it will not shut off. It just keeps running. When the compressor is fully charged with air and I manually shut it off and turn the unit back on it is fine. But as soon as some of the air gets drained and the motor turns on again (like it's supposed to) it will not shut off automatically like it's supposed to once it gets fully charged. Has this ever happened to you on one of your garage air compressors? Any help would be appriciated. Thanks in advance.Can anyone give me advice on why my garage air compressor won't shut off?
You need to readjust the ';cut-out'; pressure on the switch.





It's a little challenging, but on the back of the cover for the switch is directions.Can anyone give me advice on why my garage air compressor won't shut off?
If the pressure keeps going up into the red zone it's the regulator switch. If it keeps running, but the pressure doesn't keep climbing it could be worn out pistons or a leaky relief valve.
If your air compressor is the kind with a regular piston air pump, and a steel tank, there will be an air pressure control switch on the tank, to keep the pump from making too much pressure and possibly blowing up the tank. That shut-off control switch on it-operated by air pressure build-up in the tank, might be bad.


But, if it has the diaphragm compressor on it, then it is designed to run all the time, when its plugged in, or turned on.


It may be idling, but not compressing the air, when you aren't using air. That type also has a pressure control switch, but it operates differently than the larger pump That switch allows the air to bypass the pump, but close as soon as you need air., but it keeps running all the time.
take the cover off the pressure switch and see if there is anything loose in there. try to clean it / adjust it...


there are contact points in there that might be sticking,


and need to be filed..


unplug it first...
Pressure switch is bad. Not too expensive to replace. Any electrical supply house will have one.