Blowing off valve

by Mark

I have a 5Z630 air compressor and the pop off valve that is located on the center cylinder blows off continually while running. My question is: What causes this and how would I repair it? ( I have changed safety valve already )

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Bill says...

Howdy Mark.

You have a multi-piston compressor, and I suspect that the compressed air flows from piston to piston, increasing pressure as it goes, and then flows from the last cylinder into your tank.

That being the case, there must be a check valve between pistons to ensure that the higher pressure doesn't flow back towards the low pressure piston.

If that check valve has failed, then the higher back pressure could blow the PRV.

Cheers,

Bill