OT-Air compressor question?

[JIPJOBXX]

I noticed my little three gallon air compressor yesterday would only pump up to 30 lbs and that was it. I tighten all the connections and made sure the relief valve was not leaking by and still it only will run up to 30 lbs instead of 125 lbs. Could the pump itself be just worn out? I know how these little unit operate with the reed valves and all. I took the head oft and everything looked ok on the top end. Just wondering if anyone else had this happen to one of these little units. Jon

http://www.kmart.com/shc/s/p_10151_10104_9990000032739811P?sid=KDx20070926x00003a&ci_src=14110944&ci_sku=9990000032739811

[Don Coatney]

Does the compressor shut off at 30 PSIG?

[JIPJOBXX]

No it just keep on running and I did check the check vlv that open when the compressor is running and it doing it thing. I think I may just buy another one as they are dirt cheap but I wish I could figure this one out?

[Rusty O'Toole]

Are you sure it is only 30 PSI? Did you try a different gauge? Is there an air filter and is it clean?

[Eneto-55]

Yeah, I know - really old thread.  But I don't like to clutter the site by staring a new one every time I want a bit of advice.

 

I like to have a small air compressor that I can carry out to our garden shed to air up the tires on our mower (no electric out there), and so when our neighbor had auction, I bought his.  When I tested it later I found that it didn't shut off as it's supposed to, and just kept going until the safety release pops out.  I pulled the automatic pressure shut off switch and saw that it was plugged with rusty sludge.  Cleaned that out & got it working again, but I have two questions.

 

Well, first a comment.  There are two reasons this happened. One, the user (I now suspect this had belonged to my neighbor's son-in-law, because I know that my neighbor always takes good care of his stuff) didn't drain the tank regularly to get accumulated water out.  Two, it's a design flaw.  This switch should be located as high on the tank as possible, to avoid water & other particles getting into the switch.  Instead, it is mounted pretty low on the side of the tank, low enough that it angles down.  (There are two types of these switches, this cheaper type that is not adjustable and is installed directly into the tank, and the adjustable type that is a part of the main pressure control unit.)

 

I've been thinking of installing a section of tubing, or at least a 90* elbow to get this switch a bit farther away from the water in the tank.

 

OR, I just need to clean out the tank really well to get rid of as much of the junk in there as possible, and then just keep after it to keep it drained well, like I do with my other air compressor.

So, how would you all suggest getting that junk out of the tank?  Should I put a bunch of hot water in there, slosh it around, then drain it again, or is there a better way to do this?  As difficult as it was to get the rusty junk out of the switch, I don't have a lot of confidence in just sloshing water around in there, and I also don't want to put acid in there.

 

Any ideas?

[Kilgore47]

If the tank is that old and rusted you may need to retire it.  These are pressure vessels and designed to hold the original advertised pressure.  The lack of maintenance you described may have compromised the tank wall thickness.  If the tank wall has become too thin the tank can fail with catastrophic results.  The only way to insure it is safe would be to have the tank pressure tested and that would probably cost more than you paid for the compressor.

[Eneto-55]

I don't think that it is very old, and maybe I made it sound worse than it is.  It is just rusty water that is somewhat thickened.  The major reason for the problem, I think, is the design that put the pressure switch so low on the side wall of the tank.   It is supposed to shut off at 155 lbs, but cycles off at around 145.  I held the pressure release in a couple of times before I fixed it, up to the indicated 155.  Maybe not too smart in retrospect, but just telling what I did.

[Kilgore47]

Sounds like you have already pressure tested the tank.  Glad it went OK.  Your idea of moving the switch to a higher location sounds like a good idea.  Some tanks have larger bungs that can be removed for inspection and cleaning.  There should be a date on it somewhere telling when it was built.

 

A friend was given a compressor recently but the tubing from the compressor to the tank was missing.  Told him that was an easy fix.  I went over to look at it and when I stood the tank up we could hear rust rolling around inside.  That machine was built in 1997.  We decided to put that one in the scrap pile.

[Los_Control]

Will give you my honest opinion. Thanks for the reminder to drain water out of my tanks 

 

I really think this may be one of those areas we might be over thinking it. Compressed air creates water and you just need to stay up on it.

You could use a acid and clean it perfect ... then use it and going to re-create the same situation.

I would suggest rinse it out with water a few times, watch how clean the water is when you drain it. When it comes out clean to your satisfaction, call it a day and crack a beverage.

Then just keep draining it when done with it.

 

In the past when I was 30 years old I was a manager at a Bandag retread shop. Just incredible the amount of air we used. Picture if you can a chamber that holds 30, 11 R-24.5 semi truck tires. And fill it with 200 psi ... we had 2 chambers and changed both twice a day sometimes 3.

That shop when we opened it, had a 60 hp 3phase and it did the job. When you loaded a chamber And started loading it, Just shut down the shop for 20 min while the compressor caught up ... every tool in the shop was powered by air. Break time

After  a year or so, we put in a rotary compressor and was amazing, we could load a chamber and keep on working. The 60 hp was still there, just as a backup.

 

What we did for maintenance,  Every Friday we drained the tanks before going home. Twice a year we call in a mechanic to do a service with new oil/filters.

We seldom had a broke down air compressor.

 

I have a little porter cable pancake compressor under the bench. Is perfect to throw in the back of the truck and go to a job and run my nail guns ... or fill tires.

It shuts off at 150 psi, I swear it gets over 125 psi and it starts to rattle and works so hard ... I want to step away from it. My wife ask "whats wrong with that"

I dunno, just cheap China junk.

 

Years ago as a carpenter, my portable compressor went out ... at lunch time I went to Shucks auto supply and bought a $99 ... Holy crap I hated that thing, it worked well. Just weighed a ton. I wished it would die, just kept going. Thing was so heavy to carry around.

I later bought a porter cable and worked fine for years ... while the new one I have is iffy

 

See where I am going @Eneto-55I am the guy that service my lawnmower once a year, I oil the wood on my garden tools ... just clean it best you can and run it.

Edited May 27, 2021 by Los_Control