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Old 01-04-2015, 09:31 PM
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Air compressor pressure switch leaks

I've got an Ingersol Rand 7.5HP 80 gallon compressor that is right at 3 years old now.

It leaks air at the pressure switch. Sounds like it's inside under the cover. It isn't consistent. Sometimes it doesn't leak and sometimes it does. When it does leak (after sitting and turned off) it will bleed the air pressure down more sometimes than others.

Do I try to repair this or is it better to just replace it?


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Old 01-04-2015, 10:17 PM
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Dirt and corrosion can get in the valves and cause those problems. IF it's not working now....is there a reason not to try to fix it? I would take it apart just to see how it worked and hope to get lucky on an easy fix.
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Old 01-04-2015, 10:25 PM
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When one of mine started doing that. I took it apart and found a diaphram from a hardware store well pump controller switch fit it.. Problem fixed..
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Old 01-05-2015, 08:08 AM
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i'd go with replace it

taking it apart my cause more problems then fix. they are cheap. if it's leaking at the threads thats a fix, if it's the diaphram then no replace it.
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Old 01-05-2015, 08:13 AM
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The best price I can find for the exact replacement is $88.
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Old 01-05-2015, 08:59 AM
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Unloader valve?

Roger, Are you sure its not the unloader valve leaking? Leaks are a common problem on the tubing fitting at the unloader valve. Also the schrader valve being loose or the tab coming out of the pressure switch that operates the unloader valve being slightly misadjusted(barely touching the schrader valve stem). In that case the tab just needs to be bent a tiny bit away from the valve. If the unloader valve continues to leak air after the compressor has shut down at its high pressure setting,(should just hear a hiss when it unloads the compressor valves) the tank check valve on the compressor pump outlet may have debris in it or is faulty. You may consider applying some leak soap to make sure exactly where its leaking. If it is indeed the pressure switch diaphragm and it has to be replaced, you can likely find a generic replacement such as a Square D for way less than $88. Try Amazon.com.
Nolan
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Old 01-05-2015, 09:15 AM
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Quote:
Originally Posted by OLNOLAN View Post
Roger, Are you sure its not the unloader valve leaking? Leaks are a common problem on the tubing fitting at the unloader valve. Also the schrader valve being loose or the tab coming out of the pressure switch that operates the unloader valve being slightly misadjusted(barely touching the schrader valve stem). In that case the tab just needs to be bent a tiny bit away from the valve. If the unloader valve continues to leak air after the compressor has shut down at its high pressure setting,(should just hear a hiss when it unloads the compressor valves) the tank check valve on the compressor pump outlet may have debris in it or is faulty. You may consider applying some leak soap to make sure exactly where its leaking. If it is indeed the pressure switch diaphragm and it has to be replaced, you can likely find a generic replacement such as a Square D for way less than $88. Try Amazon.com.
Nolan
Makes sense. Thanks. I'll check those things.
I would think if it were anything else, I think the leak would be the same at all times.

Btw if it does turn out I need to replace it, I couldn't find any generics with an unloader, 3 ports, 140-175 psi, without a lever switch and for 7.5HP ratings. I think I need at least 25 amps for that.
I'm also leery of off-shore made parts you see on ebay. If I could find a Square D, that would be good but that may not be any cheaper than the IR factory replacement part.
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Old 01-05-2015, 09:36 AM
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Leak test it

Roger, Shut the power off to the compressor and apply some leak soap to the diapragm area and the unloader valve and fittings. Crank it back up with the cover off the pressure switch so you can determine exactly where its leaking. I can probably walk you through the troubleshooting once you determine the source of the leak. Nolan
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Old 01-05-2015, 11:44 AM
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???? About Compressor

Roger, I just realized you said it was 7.5 HP and its 230volt single phase according to your photo. It does have a motor starter on it doesn't it? 7.5 HP is too much current for normal pressure switches. Usually 5hp and up have starters when on single phase 230v. Unless you have some special built switch designed for the duty? On compressors with motor starters, the pressure switch only sees pilot duty current to pick up or drop out the motor starter. Let me know what you have there with perhaps more photos and I'll try to find you a less expensive switch. Did you leak test it yet? I have to go work for awhile, I'll check back in later. Nolan
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Old 01-05-2015, 11:49 AM
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Quote:
Originally Posted by OLNOLAN View Post
Roger, I just realized you said it was 7.5 HP and its 230volt single phase according to your photo. It does have a motor starter on it doesn't it? 7.5 HP is too much current for normal pressure switches. Usually 5hp and up have starters when on single phase 230v. Unless you have some special built switch designed for the duty? On compressors with motor starters, the pressure switch only sees pilot duty current to pick up or drop out the motor starter. Let me know what you have there with perhaps more photos and I'll try to find you a less expensive switch. Did you leak test it yet? I have to go work for awhile, I'll check back in later. Nolan
Thanks Nolan.
I haven't looked yet. I'll get to it this afternoon. Yes it's got a big box on top of the motor with capacitors in it. (I had to replace 2 of them a while back.) And it is 230V single phase.



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Old 01-05-2015, 04:50 PM
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So I got some time to go out to the shop just now.

It's probably been 3 days or so since I've run the compressor (I turn it off and shut the ball valve on the compressor at the end of every day I use it.)
It was down to 75 psi so it had been leaking.

First thing I did was remove the copper tube from the switch. Air leaks out of it slowly. If I put my finger over the tube, it will build pressure.
Doesn't this mean that the check valve on top of the tank isn't holding?

I put the tube back on and let the compressor build up to 175 and shut off. The unloader makes a pretty good sound when it opens but keeps hissing afterwards.



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Old 01-05-2015, 08:14 PM
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Check valve

Tank check valve is leaking. Could be debris if you're lucky. Thats a real nice compressor, enough to run a commercial shop. If it were me I would get an exact replacement for the check valve. I've had issues before trying to make a generic fit. Let me know how it goes.
Nolan

Quote:
Originally Posted by roger1 View Post
So I got some time to go out to the shop just now.

It's probably been 3 days or so since I've run the compressor (I turn it off and shut the ball valve on the compressor at the end of every day I use it.)
It was down to 75 psi so it had been leaking.

First thing I did was remove the copper tube from the switch. Air leaks out of it slowly. If I put my finger over the tube, it will build pressure.
Doesn't this mean that the check valve on top of the tank isn't holding?

I put the tube back on and let the compressor build up to 175 and shut off. The unloader makes a pretty good sound when it opens but keeps hissing afterwards.



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Old 01-05-2015, 08:53 PM
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Quote:
Originally Posted by OLNOLAN View Post
Tank check valve is leaking. Could be debris if you're lucky. Thats a real nice compressor, enough to run a commercial shop. If it were me I would get an exact replacement for the check valve. I've had issues before trying to make a generic fit. Let me know how it goes.
Nolan
Thanks Nolan!
Sure will let you know. I'll see if I have time tomorrow to remove and inspect that valve.
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Old 01-06-2015, 10:00 PM
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So, I removed the check valve and cleaned it the best I could. It does not come apart so I just brushed it out and flushed it well.

I reinstalled it and it leaks just exactly the same. The spring must be weak.

So I can get an original part for $50 plus shipping and a replacement brand on ebay for $23 delivered.

These are so simple I decided to get the one off of ebay. After all, the original part only lasted me 3 years.

Another thing I noticed is that the unloader valve leaks a little bit too. Just barely though.
I don't think this is an issue worth doing anything about. If the check valve works like it should, the only time the unloader valve has pressure on it is when the compressor is running. It leaks so slowly, I don't think it would leak enough air to matter in the least.
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Old 01-07-2015, 10:42 AM
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Hope it works out well

You may be able to snug the schrader valve up with a valve stem tool.
With up to 175psi sitting in the tank, the check valve seal is more of a wear item than lower pressure units.
Newer brass valves and fittings are getting so junky nowadays it ain't funny.
I've worked on some real, real old compressors that have never had the tank check valve replaced, but back in the day they made REAL parts, not this light weight junk on todays compressors. I worked on one a couple years ago that was likely built in the 50's, owner said the compressor had been overhauled once, somewhere in the 80's. It runs 5-6 days a week, he just adds a little oil to it every couple months. Don't make them like they used to. Let me know how it works out. Nolan
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