Changing the cut-off setpoint on a Rigid compressor

by Andrew
(Santa Cruz, CA)

Hi Bill,

I'm using a Rigid 1.8 hp compressor for a fairly strange application: to pressurize helium gas to 2-5 psi, at 3 scfm. The rated speed of the compressor (for air) is 5 scfm, but it quickly overheats if I run continuously with helium (since helium has a much lower thermal conductivity than air). At lower flow rates (~0.5 scfm) the temperature cools off between cycles and the compressor is fine.

I don't need the high maximum pressure of 170 psi that the compressor can provide, and I'm thinking there should be less heat generated when working at lower pressures. I'd like to lower the cut-off pressure limit to 10-20 psi, but there is no obvious, accessible adjustment. If I took the electronics box apart, should there be a way to change the setpoint? Or, is there likely a relay that is fixed at 170 psi? Any ideas?

Thanks for your help,
Andrew

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Bill says...

Andrew, the cut in and cut out set points for an air compressor are typically adjustable by the adjustment nuts inside the pressure switch.

See the page on pressure switches for more info.

As always, I advise against changing the factory settings of an air compressor, as they are optimized for that compressor based on its design/build.

Your needs (which I don't really understand)take you outside of the norm, and maybe you will be OK doing so, I really don't know.

Cheers and good luck.

Bill