Sears compressor runs till it gets about 15 psi. then slows down and trips off.

by glenn
(yorktown va.)

sears 4hp single phase 115v. Sears compressor runs till it gets about 15 psi. then slows down and trips off.


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Bill says...

If it hit 15 PSI and tripped a breaker, I would suggest looking to the pressure switch.

Since the motor is slowing, I believe it is reacting to an increasing load. That load could be the back pressure from the filling tank, could be a bad check valve, could be that the motor hasn't got the poop left in it to pump air past 15 PSI back pressure, or it could be something in the pump itself.

Is the problem repeatable? Do you re-set (what is being reset, the thermal overload on the motor?) and exactly the same thing happens again?

Keep us posted, if you would.

Thanks,

Bill

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Feb 13, 2013
comp boggs down when trying to refill
by: jack

sears 15 gal compressor. Will fill from empty just fine, shuts off at correct pressure. Comp boggs down when auto switch turns on to refill (about 85 lbs). Have to lower pressure below 20 to get it to run and refill tank. Removed chk valve and cleaned, reinstalled, no change. Replaced chk valve with a new one..same result. Do you think it is the pressure valve? Thanks for your help
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Nope, I think your unloader valve is pooched.

B.

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Sears model 106.153784 - Compressor stalls

by Stanley
(San Jose, Ca 95127)

I have a old Sears model 106.153784 2HP 220 Volt compressor and the motor stalls when it gets up to around 50-60 psi. Seems the pressure is backing up to the head. I cleaned the reed values and they seem alright but still have that problem. Cleaned the spring value in the line to the tank and that seems to work with no luck. Any help would be most appreciated. You think new reed springs would help?
Thanks Stan
selket2@sbcglobal.net






Bill asks...

Hi Stanley. Thanks for visiting and writing in.

When you say the motor stalls, are you saying that the motor shaft rotation slows to the point where it stops?

If that's the case, then I suspect you have either a failing motor, or a mechanical problem with the compressor head. Either could account for the motor not being able to overcome the increasing load as the pressure builds.

That's a whole different scenario from the compressor motor continuing to run at normal speeds with the air pressure in the tank reaching a pressure point below cut-out, and staying at the pressure with the motor running normally.

Cheers,

Bill

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Oct 17, 2014
Air Compressor Issues
by: Anonymous

My air compressor starts off good then it will start pumping slow then stop. We recently moved and it worked fine I'm not sure if turning it on its side during the move has anything to do with it. Can anyone give ideas how to repair. Thanks

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sears runs for less then a min, then shuts off

by mark
(canton, oklahoma)

runs for less then a min, then shuts off. will not restart for a while. does not run enough to ever build pressure.

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Bill says...

Mark, I suspect from the info provided that your motor is going off on thermal overload, but I don't have any idea as there are so few details in your post.

If the compressor runs for a minute, there should be some pressure buildup in the tank, even if just a bit.

See the Troubleshooting section on the site map page for links to pages that might help, and then add a comment here with a specific question based on what you found.

Cheers,

Bill

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Stops pumping at 60psi

My sears compressor starts pumping fine until about 60psi and then the pump stops and the electric motor keeps running squealing the belt.when i shut it off and turn the pulley by hand the pump turns free and easy.

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Bill says...

Mmmm, yes, that is odd.

As the pressure in the tank increases towards cut out pressure, the load (the work the pump and consequently the motor has to do to pump more air) increases.

So, it seems to me that as the load increases, and perhaps the heat that is generated by the pumping process, is causing something to bind in the pump, stopping the pump sheave, and forcing the belt to move through the sheave groove instead of rotating the sheave, and this is the squealing sound you hear.

You say that you remove the belt, and the pump sheave turns easily by hand, which seems to contradict what I've just said.

Unless, the time it takes you to disconnect the belt allows the unit to change (cool?) in some way that relieves the binding.

Bill

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