Porter Cable Job Boss compressor will not stop running (not pressure switch)

by Ryan
(VT)

Hello: I have a Porter Cable Job Boss compressor, that will not stop running. I actually have two, one that works fine. I took the pressure switch of the working one and tried it on the one that would not shut off. No luck it will still keep building pressure.

Any Ideas? Thanks Ryan

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Bill says...

Ryan, it is the pressure switch that turns the power off and on to the motor. If the motor continues to run to the point where the PRV valve lets go, then that power has to be coming from somewhere.

Put a multimeter on the power line from the switch to the motor when the pressure is past the normal cut out pressure level. If power is still flowing to the motor, then the pressure switch has not tripped off.

That may be that you are really unlucky and the second pressure switch has failed too, or, it might just mean that you wired the replacement incorrectly. You need to check that out.

Cheers,

Bill