Air compressor questions

Homerboy

Lifer
Mar 1, 2000
30,890
5,001
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I have a small home air compressor that I use to simple tasks around the house (filling up tires, nail guns, etc) I've had it for about 10 years or so, but lately, the compressor doesn't seem to turn itself off - I have to admit I'm a little scared to operate it so it doesn't blow up or something on me :)

Anyways, I have to admit, I'm not too familiar with the functionality of such things. I'd like it to auto shut off when the gauge on the right hits ~100psi but it doesn't seem to be doing that on it's own. The center black "knob" does allow for it to release air depending on what the pressure gets to, but again, it never actually shuts off. It just runs and spits air out the release valve based on that center knob's position.

How do I adjust this thing? What am I missing here? Educate me please!

Thanks!

geid92-img_20191229_111737.jpg
 

pcgeek11

Lifer
Jun 12, 2005
22,347
4,973
136
It should shut off at 150 psig as per the label.

Under the cover there should be a pressure switch that cuts power at 150 psig and then turns it back on when it gets to a set point below that.

If it doesn't turn off on its own the pressure switch is probably faulty and needs to be replaced.

It does have a pressure relief valve ( the one with the ring in the pin ) that should prevent anything from blowing up.

This should get you close so that you can locate and replace the switch. Yours may be easier to get to with the cover off.

 
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Greenman

Lifer
Oct 15, 1999
22,237
6,431
136
It should shut off at 150 psig as per the label.

Under the cover there should be a pressure switch that cuts power at 150 psig and then turns it back on when it gets to a set point below that.

If it doesn't turn off on its own the pressure switch is probably faulty and needs to be replaced.

It does have a pressure relief valve ( the one with the ring in the pin ) that should prevent anything from blowing up.

This should get you close so that you can locate and replace the switch. Yours may be easier to get to with the cover off.

It could also be that the piston ring is shot and it never gets to it's maximum pressure. I have a small compressor that never reaches shutoff pressure. I pulled it apart, the seal on the piston was clearly shot, and the new part was $60 bucks. The compressor was a $100 brand new, and I've since gone to electric nailers for trim, and have 3 other compressors. The dead one ended up in the trash.
Oilless compressors tend to eat up the piston seal.
 
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BoomerD

No Lifer
Feb 26, 2006
66,260
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My Porter-Cable pancake compressor died about 3 months after the warranty expired. It runs fine...but won't build pressure. The possible repairs will be nearly as costly as replacing it...so I did...with a Ridgid pancake compressor.
 
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Greenman

Lifer
Oct 15, 1999
22,237
6,431
136
My Porter-Cable pancake compressor died about 3 months after the warranty expired. It runs fine...but won't build pressure. The possible repairs will be nearly as costly as replacing it...so I did...with a Ridgid pancake compressor.
I don't buy oilless compressors anymore because I use them to much. They simply don't last.
 

BoomerD

No Lifer
Feb 26, 2006
66,260
14,690
146
I don't buy oilless compressors anymore because I use them to much. They simply don't last.

For the kinds of use you put them through, that makes sense. For me, I might use one lightly for a few days this year, not at all next year, repeat until it dies.
 
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Homerboy

Lifer
Mar 1, 2000
30,890
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so what's the recommendation here? Just let it keep running and see if it shuts off at 150psi on the right hand gauge?
what's the knob in the middle for then? It's never going to get to 150psi as air starts escaping much lower than that depending on where that knob is set.
and what's the gauge on the left telling me?

Thanks again for the education!
 

pcgeek11

Lifer
Jun 12, 2005
22,347
4,973
136
so what's the recommendation here? Just let it keep running and see if it shuts off at 150psi on the right hand gauge?
what's the knob in the middle for then? It's never going to get to 150psi as air starts escaping much lower than that depending on where that knob is set.
and what's the gauge on the left telling me?

Thanks again for the education!

The gauge on the left is telling you the pressure in the tank. The gauge on the right tells you the pressure downstream of the regulator going out the hose connections.

That knob in the middle is a regulator and regulates the air pressure put out the hose.

Back the regulator off all the way turning the knob to the left until there is no pressure on it. If the regulator still leaks when it is backed off it is defective and needs to be replaced.

Then run it and allow the pressure to build up. At about 150 PSI it should turn itself off. If it doesn't shut off at about 150 psi then the pressure switch is defective. If it never gets to 150 psi than the compressor is defective.