* Compressor won't shut off with regulator set below cutoff pressure

by Dave Loiselle
(Cathlamet, WA USA)

I have an auxiliary braking device with a small compressor with a storage tank and a combo filter and regulator. With the regulator set below the 120psi cutoff the compressor runs continuously. With regulator set above 120psi cutoff works normally.

Comments for * Compressor won't shut off with regulator set below cutoff pressure

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Oct 20, 2017
Compressor output
by: Dave L

I meant to mention that the compressor output is only 1.27cfm.

Oct 20, 2017
Regulator relieving
by: Bill

If the regulator is relieving as the pump is running, the regulator is installed backwards.

Air should only relieve from a downstream air line that is at higher pressure that the new setting on the regulator.

There is an arrow on the body or head of most regulators indicating the flow of air FROM THE TANK, POINTING DOWNSTREAM towards the air line and point of use.

Oct 20, 2017
Relieving regulator
by: Dave L

Yes, I believe the answer is that the relieving regulator is purging air faster than the compressor can supply it. Apparently the replacement pump does not have adequate output volume. The original pump has no markings that I can use to determine the manufacture. The only answer would be a higher output pump.

Oct 19, 2017
No leaks
by: Dave L

The only thing not in circuit is the compressor. I substituted an air line from my air tank for the air line from the compressor at the storage tank.

Oct 19, 2017
Re regulator
by: Bill

Regarding this "I have tested for leaks by substituting an external compressed air source for the pump.", is the external source being plumbed through the same F/R?

Oct 19, 2017
No leaks
by: Anonymous

The compressor is new as is the filter/regulator. I have tested for leaks by substituting an external compressed air source for the pump. I have left the device with the pressure tank pressurized over night and it holds pressure.

Oct 19, 2017
Compressor runs on
by: Bill

Might have to do with a crack in a seal or diaphragm in the regulator.

Can you feel any air escaping from the regulator while the compressor is running with the pressure set below cut out?

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