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Unloader valve leaks when compressor running?

Published Categorized as Uncategorized 6 Comments on Unloader valve leaks when compressor running?

by joe
(ogilvie, mn)

Unloader valve only leaks while compressor is running?

The Unloader valves on two pressure switches
The Unloader valves on two pressure switches


Joe, the air compressor unloader valve is supposed to open when the air compressor reaches the cut out pressure level and the motor stops.

When the compressor starts again, the unloader valve is supposed to close, to ensure that the compressed air that is being generated by the air compressor pump is directed into the tank.

You don’t indicate what your compressor is, or what the pressure switch / unloader valve combination is on your air compressor making it harder to diagnose the problem and solution.

In the photo above you can see the pin that protrudes from the side of the pressure switch. It is this pin that toggles this unloader valve.

So, first you have to make sure that the unloader valve is actually opening and closing by monitoring it while the air compressor runs up to cut out pressure and stops.

Then, if the unloader is actually working, the problem is probably a leaking unloader valve.

Dismantle it, clean it, reassemble it, and test, or just replace it.

By Bill Wade

About Air Compressors has been helping folks with their Air Compressor Problems since 2002 online. We're a community of DIY and Compressed Air professionals who are keen to support everyone across the globe with their air compressor issues and troubleshooting. Whether you're trying to identify an old air compressor, or troubleshoot an error code on a sophisticated new industrial air compressor - the community at About-Air-Compressors.com is here to help you

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