Pressure switch won't shut off

by Mike Blankinship
(Melbourne, FL)

Pressure switch replaced, compressor still won't shut off when psi max is reached. What else can it be?

Mike

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Bill says...

Mike, pull the plug, drain the tank down to zero PSI, close the drain, and plug the compressor back in.

Based on your comment, it should start fine.

Now, you say that it keeps running, even though the pressure in the tank has passed the cut out pressure level? When you replaced the switch, what is the cut out pressure level for the new switch?

As you watch the compressor run, does the pressure build until the PRV pops? What pressure is that at please. By the way, if the PRV pops, shut the compressor off and let it bleed down.

If the compressor starts when you plug it in, and the pressure keeps growing to the "blow the PRV level", then the switch has failed, again, or it's wired wrong.

At cut out pressure the switch, if it's working and wired correctly, will trip.

Inside the switch cover, points will open, and electricity can no longer flow to the motor and it stops. If this isn't happening, and pressure has gone past the actual cut out pressure level of the switch, then it's got to be the switch that is the problem.

Cheers and good luck.

Bill