My air compressor doesnt shut off when it reaches 125psi like it should??

by Jason
(Grand Blanc Mi)

It should start at 90psi and shut down at 125psi. It just continues to run and I do not know why?? When I mess with the switch from off to auto it did breifly stop yesterday but after another switch up and down it again started to run and will not stop??

Does anyone know what could be causing this? How can it be fixed? Also my compressor is a Coleman Black Max 27 gallon 5hp oiless compressor verticle style.

Does anyone know where the air filter is located?? Shouldnt it be cleaned/checked or changed from time to time?? Any answers would be great. Thanks

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Hello Jason...

What happens when your compressor doesn't stop? Does the pressure relief valve pop open?

Regardless of that, it sounds like your pressure switch is pooched.

The pressure switch senses the pressure inside the tank and when that pressure reaches the set point, it both shuts off electrical power to the motor, and unloads the air compressor.

If this isn't happening, then you may "enjoy" a catastrophic failure of your air tank. Get it fixed.

As to the air filter, your compressor will have an air intake port up around the top of the compressor head. Usually it's got a black plastic doo-dad screwed into it and there will be a hole in the bottom of this into which free air flows as the compressor works. That air passes through an intake filter inside the plastic housing before it gets to your cylinder.

That unit can be unscrewed from the compressor head, the cover should pop off, and the filter inside can be examined and, if necessary, cleaned.

Bill