Need Air Compressor Help

[MarkSLSmith]

Folks,

I thought my pressure switch was going bad, but now I'm not so sure.

Scenario: my air compressor lives in a shed behind my garage (about 6 in. between them).  It is plugged into an outside GFI 20A outlet at the rear of the garage.  I only turn the compressor on when I need it, due to my apparent inability to eliminate leaks from the system.  This arrangement has been flawless for about 5 years (no GFI trips at all).  I think the air compressor is about 25 years old, but it has been a sterling performer and I want to continue to use it.  It is a Porter Cable CPL6025, 6 gal tank.

The GFI outlet started tripping a couple of weeks ago.  When I reset it, the air compressor would work, but often the next time I turned it on, the GFI would be tripped again.  I thought the pressure switch was starting to fail.  One thing to note, the status of the GFI is a pain to evaluate due to the close proximity of the shed to the garage.

When I bring the air compressor into the garage, it appears to work normally.  So now I'm worried that the GFI outlet is the problem and not the pressure switch.  

Do GFI outlets "wear out"?  Is there test for the pressure switch to confirm that it's working and has no intermittent problems?  A new pressure switch is not inexpensive, so I want to be a bit more sure that I need to replace it before shelling out the money.

Thanks,
Mark

[Roly]

Since most gfci's do not have any over current protection and it sounds like you find it tripped the next time it is started I don't see where the pressure switch would be tripping it.  I would bet maybe a wet gfci or a damaged cord that may get wet between uses.   Yes gfci's have been know to go bad over time.  Is it possible to move the gfci in the garage and place a normal receptacle outside wired off the load side of the gfci ?   Was the outlet in the garage gfci ?   Roly

[TDKPE]

A bit of a recap, but yes, GFCI’s can get more sensitive and trip at a lower threshold over time.  May also be a bit of leakage current through the many bits that make up the power to and even inside the motor, especially with some condensation in there.

If it were me, I’d replace the GFCI receptacle first.  What I’d do if that didn’t work I don’t want to put down on a public forum.  

[daddo]

A few years ago, my 16 year old 60 gallon started tripping the breaker once in a while. I changed the oil and that cured it. I now change the oil every fall.
Mobile1 5w-20.

Just thought I'd give you one more thing to look for.

[MarkSLSmith]

Yes, the tests inside the garage were on an outlet that was not GFI.  Your comments are making me think it is the outlet; or at least, the suggestion to change the outlet first makes more sense.  It's difficult to access, but doable.  I'll try that first.  

Unlike some compressor owners, I have changed the oil at least once.  I think it was 2-3 years ago??  I should have wrote the date down.  Maybe I'll just go ahead and do it while the compressor is out of the shed.

Thanks, I post an update once I change the outlet.

Mark

[Roly]

Yes, the tests inside the garage were on an outlet that was not GFI.  Your comments are making me think it is the outlet; or at least, the suggestion to change the outlet first makes more sense.  It's difficult to access, but doable.  I'll try that first.  

Unlike some compressor owners, I have changed the oil at least once.  I think it was 2-3 years ago??  I should have wrote the date down.  Maybe I'll just go ahead and do it while the compressor is out of the shed.

Thanks, I post an update once I change the outlet.

Mark

Can you plug it in a different gfci ? if it trips  on a different gfci outlet it may be a problem in the compressor but I would bet on the gfci outside being bad.  I have also seen where there would be a zillion ants in the box with the cfci which may trip if it becomes damp.  Roly

[TDKPE]

Changing the oil is good.  If it’s in a cold room, which it seems it is, you may need to run thinner oil to ease cold starts.  

Having said that, GFCI receptacles don’t trip on over current, as Roly pointed out, so I think you’re on the right track starting out with the receptacle.

[Roly]

Changing the oil is good.  If it’s in a cold room, which it seems it is, you may need to run thinner oil to ease cold starts.  

Having said that, GFCI receptacles don’t trip on over current, as Roly pointed out, so I think you’re on the right track starting out with the receptacle.

Tom their cold is your balmy weather.  Don't think oil is the issue but it is humid and condensation in the oil may be a problem so I would change it.   Roly

[TDKPE]

Oh, yeah - Sugarland.  


But that does sort of reinforce the possibility of condensation in the motor, control, and/or wiring as potential contributors to nuisance trips, especially if it happens on the first start but not after things heat up.  If that indeed is the case.  

[MarkSLSmith]

I only have one other GFI outlet near the garage.  I tested the compressor on it, and it seemed to work fine (about 5 cycles of turning on and off).  So the outlet seems to be emerging as a leading candidate. 

I'm thinking about jumping to this option:

"What I’d do if that didn’t work I don’t want to put down on a public forum."

There's no water sources anywhere near the outlet, and the shed shields the outlet pretty effectively from rain.  If I ever move, I could install a GFI outlet to be more code compliant (although, as the owner of a 50 yr house who does a lot of his own repairs, code compliance is perhaps more of an ideal than a reality).

Any thoughts?

Thanks,
Mark