Air compressor not unloading

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I have a Husky (Campbell Hausfeld) 80 gallon 2 stage compressor and it does not unload when it reaches capacity and when I drain air down it kicks reset switch.

Campbell Hausfeld 80 gallon air compressor
Campbell Hausfeld 80 gallon air compressor

Where is the unloader valve located on the compressor?

Hello there.

For many air compressors, the unloader valve is adjacent to or part of the pressure switch.

It’s can be a lever protruding from the side of pressure switch that toggles the unloader valve open and closed as the switch cycles.

Other pressure switches have the unloader valve internal to the switch. These can be identified as there is an air line inserted into the bottom (typically) of the pressure switch.

Unloader valves can become plugged up, so when you find yours, after dumping pressure and unplugging the compressor, disassemble and clean it and see if that solves the problem. If not, you may need to replace it.

If you add a photo of the pressure switch on your air compressor, that would sure help.

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I have an old Devilbiss 342 and the unloader valve is not working.

Does anyone know the correct location of the valve? I believe it is in the line that I am pointing to in the 4th photo.

Also what is the recommended fix.

Please help I really want to get this old bear running again it’s been in my family since 1979.

First, unless that room is always below 100° F, please get rid of the PVC pipe. If it blows, your insurance most likely won’t cover any liability.
On to your question:
Probably not. What is/are your symptom?
Won’t hold air, won’t restart? Something else?