Safety valve blows?

by Julia
(Portland)

When using my CP compressor (2 HP, 8 GAL) to power framing nail gun, it builds pressure rapidly, then the safety valve blows, and this repeats. It used to build pressure, then shut off until it needed to replenish the pressure. Why is my safety valve engaging so often? Is this OK?

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Hello Julia... no, this is definitely not OK!

What I think may be happening is that your pressure switch, the device that turns the compressor on and off based on the tank pressure levels, has failed on the cut out side. Instead of stopping the compressor when the tank pressure reaches the normal cut out pressure, maybe in the 120 PSI to 150 PSI range, the pressure continues to build past that point, adding pressure to the tank, until your pressure relief valve lets go.

If this were my compressor I would not use it again until I had that fixed, as right now, if the PRV should fail to, then you may have a catastrophic pressure failure.

Please get this corrected before you use the compressor again.

Cheers,

Bill

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Model 93271 motor stalls?

I have a model 93271 that runs up to 60psi then motor stalls out. not sure what to fix
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If the motor stalls while the air compressor is pumping up to cut out pressure, then it could be because the compressor motor now lacks the power to overcome the increasing load as the pressure in the air tank builds.

That suggests to me that the motor may be getting tired.

It might be tired as it is wearing out, or it might be that it is not getting enough power. If you are using an extension cord, move the compressor to where you can plug the cord directly into a socket that has lots of power. That means that everything else using electricity is not pulling power from the same circuit while you are trying to run your air compressor.

It could also be a run capacitor failing, if your model has one. There is a page on this site about how to check your capacitor(s).

Or, it might be an issue with the pump itself.

If it were me, and the power supply was good to the motor, then I'd get the motor checked out, first the capacitors and then a load test on the motor.

Good luck. If you care to, give us an update as a comment on this post, won't you?

Bill

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Oct 31, 2012
I had the same problem
by: Neil

After much ado I discovered that the drive belt was slipping. Don't assume that is not your problem (as I did) go and check it. Look closely at the motor pulley when it "stalls" and you might find that it is spinning freely but slipping on the belt. It was not the motor that was stalling but the compressor was stalling due to a worn belt!

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Central Pneumatic 67501 oil over-fill?

by Kevin
(New York)

I just purchased a Central Pneumatic Model 67501 compressor, 2 H.P. 8 gallon.

I over filled the oil sump and now have to drain it.

Even though the oil sump is over filled, the oil is so clear you can't see it in the sight glass ! Any ideas on how to check the level after start-up, if you can't see it in the sight glass ?
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If this were my compressor I would open the drain plug and drain out all of the existing oil.

Then, I would add a compressor oil that has a bit more color in it. For example, the oil in my air compressor sump is amber in color when new, and is easily visible in the sight glass window.

Not a great solution, I know. :-)

Cheers,

Bill

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95275 compressor will not run?

by Rick Drury
(Jacksonville, Fl)

Central Pneumatic 95275 air compressor (Photo: www.harborfreight.com)

Central Pneumatic 95275 air compressor (Photo: www.harborfreight.com)

Compressor sits in a barn usually plugged in with all valves closed leaving it charged but air hose not charged.

It worked great 3 weeks ago but now will not run to fill the air tank and line up. I pushed the reset button to no avail.

What can I do to get this thing to work. The model No is 95275

Rick Drury
Jacksonville, Fl 32218
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Rick, the obvious first question is what is the pressure in the tank? If the tank pressure is above cut in, your compressor will not turn on.

Next question is, are you getting power to the compressor?

Next, if power is getting to the compressor, is it actually getting through the pressure switch to the motor circuit? If power comes in to the pressure switch, but not out to the motor, that indicates to me that the switch is your problem.

For more things to look at when an air compressor will not start please see the troubleshooting section, click the links about why air compressors won't run, and do the checks noted.

Post a comment here with what you found or if you have more questions, Okay?

Cheers,

Bill

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Jul 28, 2013
Low pressure
by: Clarence

It stops at 70#, rather than 100#, and starts proportionately low.

What can be done to get the specified pressure range?
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If it is a new issue, then I suspect that the settings on your pressure switch have either been altered, or the switch itself is failing.

If an adjustable switch, modify the settings to suit. If not, then consider a new pressure switch.

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