Sullair compressor slowly loses air pressure

by Jim Fyfe
(BC Canada)

Sullair compressor slowly looses air pressure when unloaded causing periodic loading/unloading cycle


We have a 950 x 350 compressor that has recently begun to lose some air when unloaded at about 150 psi. This causes the compressor to slowly cycle to make up the air. The air doesn't seem to be come through the service valve. Also, I'm wondering if the unload setting should be there higher (180 psi)?
Thanks, Jim

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Jun 04, 2015
More info
by: Carl

Like Doug said, could you provide more info about your system, do you have a dryer in the system? Filters inline? When you say "periodic onload/ offload" do you mean erratic?

Jun 03, 2015
sullair compressor problem
by: Jim

Doug, thanks for years your comments. Our compressor does have receiver tank. I noticed that the unit unloads at 180 psi and slowly loses air to 150 psi. It then cycles back to 180 psi.

Jun 02, 2015
pressure loss
by: Doug in s.d.ca

So, you have a tank?

It would likely have a check valve somewhere between to airend and the tank, possible leak there. Or maybe just loose connection in the lines going out.

If that seemss way off-base, please describe the setup more completely.


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