craftsman electors compressor - No pressure

Hey Guys,

Im trying to fix a craftsman electors compressor for a neighbor. My big question is if you put your finger over the "outlet tube" should you be able to stop the flow? I can do that, does that mean the compressor, valves, piston, etc. Are bad and need a rebuild? Or can it be the check valve, switch or something else?
Any help is appreciated
Thanks,
R.T.

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Bill says...

R.T., it depends on what you mean by the "outlet tube"? Do you mean the tube from the compressor head to the tank?

If so, then, if you think about it, you shouldn't be able to stop this flow.

When the pump is working, it's pushing air into the tank past the check valve. As air pressure in the tank increases, back pressure develops, and your pump has to be able to pump air into the tank against that increasing back pressure.

The real test though is to re-plumb the line, empty the tank, close the tank drain, and plug the compressor in. What happens?

Cheers,

Bill

Comments for craftsman electors compressor - No pressure

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Oct 27, 2010
There is someone there....!
by: Anonymous

Holly crap--There is a real person attached to this help! Thanks fpr your answer,it's about what I thought. I'll give it a try and let you know what happens?
Thanks Again;
R.T.
Ocala, Fl.

"Life is a Beach"

____________________

You are very welcome.

Bill



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craftsman 80 gal. compressor bleeding off

by Chris Williams
(oroville ca.)

My compressor is slowly bleeding off. i have tried soapy water and can't find the leak.

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Bill says...

Hey Chris. How's it going?

Here's the thing... you compressor pumps air into the tank, and when the cut out pressure is reached, the compressor shuts off.

At that point the unloader valve opens and dumps the air over the piston to allow easier restart.

Since the line to the tank is now open to atmosphere, what keeps the air in the tank is a check valve, usually located where the line from the compressor head enters the tank.

If that check valve is leaking, even just a little bit, air bleeds back out of the tank and out the unloader valve.

This is what I thing your problem is. Pull the check valve and clean it, or replace it.

Cheers,

Bill

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Craftsman air compressor leaks when switch is in off position

Small Craftsman compressor is leaking air from somewhere near the pressure switch.

Replaced the check valve but that was not the problem.

What is interesting is that if you cut the power while the switch is in the on position, the pressure will hold.

If you move the switch to the off position, it will resume leaking. Any ideas? Thanks to all!

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Bill says...

You are very welcome... but there is no all, it's just me! :-)

If it's leaking air from somewhere near the pressure switch, where? The only place, normally, air would bleed out near the pressure switch is the unloader valve, and that is normally because the unloader valve is open when the compressor shuts off on high pressure cut out. This allows the trapped air over the piston to bleed off. If the check valve is leaking, then all of the air in the tank will leak out then too.

Use a solution of dish soap and water and slather the fittings around the switch to identify the leak.

My money is still on the unloader valve!

Dumb question, perhaps, but why turn the switch to off? Let the compressor shut off on high pressure cut out, and, aside from a quick burst of air out of the tank to drain it, don't shut it off. Just unplug it.

Cheers,

Bill


Comments for Craftsman air compressor leaks when switch is in off position

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Jan 11, 2011
Thanks Bill
by: Anonymous

Bill,
Thanks for your expertise. There is a small valve attached to the switch, (a needle valve) and I think that is where it is leaking. Turning it off and pulling the plug were just part of the experiment to try and isolate the problem. I've been reading quite a bit and it sounds like the unloader (bleeder?) valve to me as well. It's a small Craftsman, model 921.153120, and so far I haven't really been able to find the part. Is it part of the switch, in which case I will have to purchase the whole thing? I purchased the check valve from master tool repair, but their website is currently down. I checked the sponsors on your site and didn't have any luck there either. If you have a resource I would appreciate it. Thanks! Ron

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Ron, for the unloader valve to be leaking when the compressor is off, you must have a leak in the tank check valve. There is no place else that air could be coming from.

Turn off the compressor (pull the plug) dump all the air in the tank to zero PSI, and then disassemble the check valve assembly at the tank. I am almost 100% certain that you either have a bad check valve or there is debris of some preventing the check from seating, and that is allowing air to bleed out of the tank.

When you toggle the pressure switch to run, that flips the unloader valve closed.

Cheers,

Bill


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Sears Craftsman 1.5hp compressor won't build up any pressure

by John
(BC, Canada)

Thanks to your site I managed to troubleshoot the problem with my compressor. It's only about 4 years old and it simply quit compressing air. I was nailing some baseboard and the pressure disappeared. I checked everything - reed valves, check valve, rings, etc - but didn't initially notice that the head gasket had blown between the reed valves. Simple solution - cut a new gasket out of some gasket material. Works fine.

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Bill says... glad to hear the site was a help. Good comment for others experiencing the same problem, and this issue seems very common.

Bill

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Jan 10, 2015
Craftsman 25 gallon 125 psi stopped building pressure
by: Bill

Something's wearing out, for sure.

See the troubleshooting page about air compressors that run but don't build pressure for some things to check.

Let us know what you found.

Jan 10, 2015
Sears Craftsman Will Not Build Pressure
by: Anonymous

My 20 year old Craftsman 25 gallon 125 psi stopped building pressure. It makes it to 25 psi then continues to run but the pressure does not increase. Model 919152521

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