Compressor building too much pressure

by Pat
(cottam)

I have a husky 7hp 60 gallon compressor. It turns on builds pressure up to 135psi then "pops" the safety valve and continues to run. It won't shut off. How can I turn down the amount of psi it builds? The tank is about 6 years old. I am not sure where the adjustment is? There are 2 allen key screws on the back of the switch, one small (aprox 5/16) and the other is aprox 3/8?

thanks

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Bill says...

Pat, it didn't always do this, did it?

Although it seems to me that to have your PRV letting go at 135 PSI seems a bit odd, if your compressor isn't rated for higher than that, then that's why the PRV lets go at that pressure.

Unplug the unit, and look under the cover of the pressure switch. Some of them show the pressure settings for your compressor under the lid. If it's there, what are the pressures for high and low pressure switching?

I'm thinking that you may need a new pressure switch.

Cheers,

Bill