Compressor won;t shut off automatically

by Bud
(South Jersey USA)

Campbell-Hausfeld mode;l C1071080VMSA, magnetic starter, wired for 220.

Turn on power and compressor starts fine, builds to 175PSI, then pressure switch hisses and opens points, but compressor still runs and pops safety valve.

Replaced pressure switch, problem still there.
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Bill says....

Hmmm, this is a weird one, Bud.

If you think of it, the pressure switch is just a switch. When the switch is turned off (the high pressure cut out pressure is reached and the points open) then power stops flowing to the electric motor and the motor stops.

In your case, the pressure switch is opening (at least you think it is) and the motor continues to run.

Therefore, power must still be reaching your motor even when the switch trips, and you must either have a failed switch or you have a path to the motor for power to flow even when the switch is off.

You have an electrical problem I'm sure, and you need to bring in an electrical expert to solve this problem.

Cheers,

Bill