by Jeff gibbs
(NH)

Compressor won’t shut off. Keeps running till pressure relief valve vents off.

I replaced pressure switch. Still does it.

The new switch was not exact match. Lower cut in and out pressure. 3lbs different What else could it be?

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Husky compressor won’t shut off
by: Bill

Jeff, the logical assumption is that it is the new pressure switch that has failed, and often that is right.

You know the new cut out pressure setting of your compressor?

With the tank empty and drain shut, start the compressor. Monitor the pressure build in the tank until it surpasses the cut out pressure setting of the new pressure switch by 10 PSI as per the tank gauge.

If the Husky compressor is still running at this point, then power HAS to be flowing through the pressure switch to the compressor motor, right?

That means that…

1) the new pressure switch hasn’t got an accurate cut out and it’s much higher than you think,

2) the pressure switch has failed and failed “passing”, meaning power is getting across it even if it’s “trying” to cut power and

3) when the new switch was installed you’ve connected the cord power supply to the motor side and even though the switch is cycling based on the pressure, the power cannot be cut.

Double check the wiring in the switch and let us know, will you?


Husky 7 hp 60 gallon won’t shut off at preset pressure

by Ed
(TN)

New Husky 7.5 HP air compressor

I have a 7 hp 60 gallon Husky that won’t shut off.

When I originally picked it up, I couldn’t stand it upright, so I pulled the pump off the compressor body so that it would stay upright and carried the rest laying down.

When I tried it at its original location, it filled with pressure just fine and shut off properly.

Once I got it to my house, I put the pump back onto the compressor body, lining everything up with a new belt.

I kicked it on and it pumped but didn’t want to shut off.

I have since pulled the check valve to find it pretty much obliterated. I replaced it and rechecked the operation.

It still builds up to 135 psi like it should but won’t shut off.

When it reached 90 psi, which is the on pressure, it bogged down, then again when it hit ~135. I shut off the switch because I didn’t want to tempt fate. After reading more, I picked up a pressure switch. I couldn’t get the one rated 90-135 like was originally on the compressor, but got a 90-125 with the same specs. 10 psi isn’t going to kill me.

I installed it and turned it back on.

It still builds pressure properly with the bogging down but won’t shut off. I have used a wired 220 30amp cord to a socket on the wall. Originally at the location I picked it up from, it was wired directly to the breaker.

I’m not sure where to go from here. Any assistance is appreciated.
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Ed, you’ve done pretty much everything right.

Let me ask you, you say it bogs at 135 PSI, but doesn’t shut off. Are you saying that the pressure in the tank (seen via the tank gauge) gets to 135 PSI and stays there?

If so, then I suspect the pressure switch is not “seeing” the pressure it needs to trip and shut off power.

That being the case, one of the first things is to re & re the tank check valve. You have done that.

Next, since I don’t know if this compressor is near new, try running it without the intake filter on to see if that has any bearing on the operation of the compressor.

Assuming that the power supply is good as you say, and that there are no issues with the motor failing, then the next thing that I would think needed addressing would be the valves, both intake, and pressure. That means a tear down, unfortunately.

Keep us posted, will you?

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Update – video of noisy air compressor
by: Ed

Well, I re-tightened the air line going to the unloader valve. The air stopped escaping there. But the problem still persists. I took a video of it running. You can hear the motor bog again and even some clattering from the pump, which wasn’t necessarily there before. I ran it up to 125 PSI but the pump was making so much noise, I didn’t want to push it any further. Besides, it should have shut off at that pressure with this switch. It appears as I have to take apart the pump. Any thoughts?

(Sorry, video link no longer works – moderator)