Devillbiss won't start without a belt push

by Dan Vock
(New York)

Have an older devillbiss 5 hp 15 gallon sears.


The motor initially just buzzes when first switched on, but will start to go if i turn the belt and give it a helping hand.

it builds pressure fine and shuts off properly.

On restart it buzzes again and will not turn/start if there is any amount of air left in it even if I help it by turning pulley.

Once I drain all air out it is again possible to get it going but only if i assist by turning the pulley once again.

I had both capacitors tested and they are fine. Do I just have a weak motor?

djvock@gmail.com

Thanks , in advance.
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Dan, the symptoms suggest, in my opinion, a unloader valve issue, or a lack-of-power issue.

You have ruled out the capacitors, which could have been the issue.

Make sure the unloader valve is actually working.

And, are you getting clean power to the compressor? If you are using an extension cord, don't. Plug the compressor directly into a power supply that is not being used for other appliances that may pull power at the same time the compressor is trying to run.

Then, look to the motor as perhaps needing a rebuild. See if you can get a load test on the motor to make sure, first.

Cheers,

Bill



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devilbliss pressure problems

by j
(columbus ga)

I have a 3/4 hs devilbliss single tank,Just replaced the pressure switch worked fine at first.

Then went to use after it sat a couple of days now it wont pump up past 60lb of pressure it wont shut off because it never reaches the 120lbs i have it set on.

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Bill says...

J, could be bad power supply, could be intake or pressure valves, could be a gasket failure, could be piston seals... to name just a few.

With the absence of any other information based on the checks I included on the page, I can't be any more specific than that.

Please comment with more info about what you have checked so we can drill down to the real air compressor problem.

Cheers,

Bill

Comments for devilbliss pressure problems

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Jan 31, 2014
head pressure
by: frank

Hi Bill! replaced pressure switch,and cleaned the check valve,and my compressor will not bleed off head pressure resulting in hard starting.it is an old devilbliss model.what else can i check?
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Is the unloader valve working?

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Devilbliss model# IRL6560V air compressor stalling after build up pressure

by Ricky
(NC USA )

i have a Devilbliss model# IRL6560V, 60 gal 6.5HP. if the compressor is completely empty when i turn it on it will fire right up and build pressure but once it cuts off and air is used it will not come back on when pressure is low, it just hummms until the motor overload trips. i have checked the in tank check valve, the pressure relief valve, and even had the motor completely redone and checked out including new capacitors. my question is could it be the contacts on the pressure switch not allowing enough current to get to the motor as it is an older compressor, think around a 1996 model? any other thoughts on what it could be?

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Bill says...

Ricky, from what you have written, no, I don't think it's the contacts.

What I do think your compressor has a problem with is the UNLOADER VALVE.

Click the VALVE link from the navigation bar, and then the link to the unloader valve page. Have a read. I think this is your compressor problem.

Cheers,

Bill

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Devilbiss Model # RAF5020 is clicking

by John Barrett
(Cullman, Alabama, USA)

Compressor makes clicking sound when turned on, but will not start or turn fan.

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Bill says...

Based on that limited description John, I'd be looking to the start capacitor as the problem.

Cheers,

Bill

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Nov 07, 2016
motors that won't start without help
by: Anonymous

when a motor has a start/ run capacitor, it is switched by a set of spring held flyweights.

If the weights stick in the run position rather than springing back when the motor stops, (centrifical force action) the switching will stay on the run capacitor rather than clicking back to the start capacitor position.

The fix is to blow or brush the dust and Cobb webbs out of the end of the motor (with it unplugged) and free up the stuck flyweights so they can go back to moving freely.

Mar 23, 2014
Air comp. won't start
by: Anonymous

L6560v compressor stopped working. When I turn it on it just hums. The belt doesn't turn even if I try to move it, seems locked up.
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Typically a humming air compressor is one that has a power supply problem. See the troubleshooting pages for information about that.

After you have done so, if you are still having problems, start a new post identifying what you have done, what you have found, and we'll see if we can help further.

B.

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