My compressor will not stop running.

by Rick

My compressor will not stop running. It builds up pressure, but keeps on running.


I think that it needs a new regulator but I am not sure.






Bill answers...

Hello Rick.

Thanks for your question about your home compressor. When the book about Home Compressors is ready, I'll let you know.

It appears as though you have a serious situation with your compressor, and you should stop using it until you get it fixed.

What you don't say is if the pressure in the tank reaches and bypasses the cut-out pressure point?

If the compressor keeps running, and the pressure in the tank passes the cut-out point, then eventually your PRV is going to operate to vent pressure inside the tank before it reaches a dangerous level.

If the PRV is sized correctly, then it will vent air faster than the compressor can compress it, so ultimately all of the air in the tank will vent safely.

Your compressor, however, will continue to run since it would appear as though your pressure switch has failed, and since the unit can't ever reach cut-out, then it will eventually self-destruct.

If, on the other hand, your compressor reaches a pressure point BELOW the normal cut out pressure point, and the compressor keeps running but the air pressure doesn't pass this point (say 70 PSI for example), then it's not the pressure switch. Likely it's a valve or cylinder problem then.

Either way, your compressor will do itself serious damage if it runs past it's duty cycle.

Hope this helps...

Bill

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Jul 01, 2015
DeWalt won't shut off
by: Bill

If the tank pressure reaches, and then bypasses the normal cut out pressure setting of your air compressor, the pressure switch should trip to off, and the compressor motor should stop.

It was a good move on your part to change out the pressure switch as it is this part that turns the compressor off when the tank pressure reaches the cut out pressure setting.

That it won't shut off even with a new pressure switch is a problem, for sure.

Assuming the new switch works properly, then it is possible that either the cut out and cut in settings in the new switch are different than the old, or the new switch has been wired in such a way that even if the switch trips, the motor still gets power.

If this were my compressor I'd be reviewing the wiring on the new switch to ensure that the various wires are connected properly.

Jul 01, 2015
Compressor won't turn off after reaching preasure
by: Anonymous

I have a Dewalt compressor that continues to run even after it has reached pressure. I thought it was the pressure switch so I put in a new one. It still won't shut off. Duh?

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Compressor won't shut off but pressure won't build.

I have a sears air compressor that builds pressure up to 60 psi and keeps running but builds no more pressure. It used to build pressure up to 120 psi and then shut off until the pressure would drop.






Bill answers...

Hi Jerry.

When a compressor is running it's dumping air into the tank, and when the pressure in that tank reaches the cut-out pressure setting, the pressure switch trips, and the compressor stops.

In your case, as I understand it, the compressor cuts-in at the low pressure point, and pressure starts to build in the tank until it hits around 60 PSI, and then, even though the compressor keeps running, the pressure won't build further?

First off, eliminate any leaks. It's hard to hear a leak when a compressor is running, and it may be a small leak that the compressor can overcome until it hits that 60 PSI range, and then the leak intensifies and the compressor can't get past that pressure.

No leaks?

If you've got no leaks, then it would seem reasonable that the air seals are worn to the point that the pressure can't get past the 60 PSI point due to blow back between the piston and cylinder wall.

I note similarly here.

Cheers,

Bill



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motor wont turn off keeps tryin too run when full of air

motor wont turn off keeps tryin too run when full of air

___________________
Bill says...

If the compressor motor is still running after the air pressure in the tank reaches the normal cut out air pressure level, then look to your pressure switch first as the source of the compressor problem.

If the air pressure in the tank doesn't reach the normal cut out pressure level, and since then the air compressor can't shut off as the pressure never reaches the cut out pressure level, then look to the intake valve or internal gasket leak as the possible source of the problem.

Cheers,

Bill

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not building over 40psi pressure

is it the unloader valve or the pump itself

_____________________
Bill says...

As a result of the problem, your air compressor runs continuously, will not reach cut out pressure, and will not stop running? Is that fair?

Based on your limited info, I would look at the valves (air puffing out intake port), and then consider opening the pump and checking the gaskets. These are the two most likeliest reasons.

I doubt it is the unloader valve. If you have air blowing out the unloader valve when the compressor is running, then look to the check valve being the problem.

Cheers,

Bill

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