Kobalt 17 Gallon-shutting off

by Geoff Wymer
(Birmingham AL)

I have 2 Kobalt 17 Gallon model 236005 compressors.

Both have the same issue.

When you turn on the switch the motor will make 1 or 2 struggled revolutions and then it triggers a switch that kills the power. A few seconds later it resets and repeats. This is even with the tank empty.

When I took the line to the tank loose, it would fire and run, I could even reconnect the line and fill the tank once, but when the prssure went down and tried to restart--same problem over again.

I bipassed the external regulator switch and that did not fix the issue.

Not sure what parts to get to fix this. Any help would be greatly appreciated.

Birmingham AL

Bill says...

When an electric compressor motor starts, it usually pulls more current than the electrical circuit can supply. To handle this "inrush" issue, your compressor motor has a start capacitor that adds power to the circuit, allow the motor to kick over and start, without popping an internal or external breaker.

When a compressor is starting against pressure in the tank, then this inrush assistance is even more critical to the start, as the motor will draw even more than when the tank is empty.

It's odd that you have the same problem on two compressors, yet, if they are the same vintage, perhaps not so odd.

This is what I think your compressor problem is, based on the details you provided.

If the power supply to your compressors is compromised (more appliances drawing power at the same time as the compressor) take other appliances off line while testing the compressor. The same for an extension cord, if you are using one. Both can cause compressor start and run problems.



Comments for Kobalt 17 Gallon-shutting off

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Sep 20, 2015
Kindly compressor
by: Anonymous

These compressors have a thermal switch which means when it's heats up it shuts off and in the case of Kobalt compressors even when it's like warm it will shut off. This switch is actually mounted on the motor it's self so other than changing the motor there is no fix

May 15, 2011
Continuation/explanation of the problem
by: Geoff, Birmingham AL

Thanks for the lesson. Some more facts to the story-I was an employee for Lowe's and bought both compressors after 2 customers returned them new with the issue described. It is too costly to have external company repairs done on the units due to labor costs, so we discount and sell. That is why 2 with same issue. Initially I thought they had different issues and I could make 1 good out of 2. They are both new but with the same issue. They were tried at the customer's house, Lowe's, and here at home with and without extension cords and different breaker strengths. I was wondering if it could be either the check valve or one of the capacitors on the motor? My understanding of what those do is limited. I was very excited to find your web site and to read through all your postings. It has been very educational.

Thanks again,


My money is still on the capacitors being an issue.

You are most welcome, Geoff.


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compressor starts - runs a few seconds-then stops

by Jim Clark
(Winchester, TN., U.S. A.)

Its a Kobalt 20 gal. oilless compressorJim Clark

Bill says...

Hi Jim. Can you give me a bit more info, please?

It runs for a few seconds... what, two, three?

Is the motor running and the pump pumping, or is it just the motor trying to start?

When it stops, does a fuse blow?

Any sound from the compressor pressure switch when it stops?

Are you running it plugged into an extension cord? If so, lose the cord and try it again?

Also, drain the tank fully before you try and start it again. Does this make any difference?

Post your answers as a comment on this thread please Jim.



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Kobalt compressor wount shut off

by herbie

I just put on a new pressure switch but it still will not stop when it gets to the right pressure it just goes till the safty valve opens

Hey Herbie. That's a pain, for sure. The thing is, it is the pressure that is what turns the air compressor off when the tank pressure reaches cut out pressure levels... nothing else.

So, if you've put a new pressure switch on, then either you have the bad luck of getting a bum switch, or, there may be a wiring issue.



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Aug 03, 2013
where did you get the switch?
by: Lane

I need to replace a pressure switch and have not found anywhere I can get a replacement. Can I ask where you found the switch you purchased?
You don't need to buy OEM equipment for an air compressor unless it's under warranty. If yours is not, I've added a parts store linked from the navigation bar, which shows a number of different pressure switches.

As long as the new one fits your compressor, has a similar pressure range (or is adjustable) and handles the voltage, you're good to go.


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Kobalt model #37296 Tries to start then trips breaker.

by Ron Phillips
(St Peters MO)

When I turn it on it sounds like it is struggling to turn on, then it trips the breaker. If I disconnect the copper line it runs fine. It is a Kobalt modle #37296.

Ron, put the copper line back on.

Drain the tank to empty, then plug in the compressor.

If it starts, when it gets to the normal cut out pressure setting and cuts out, make sure that the unloader valve works, will you?

Add a comment here with your findings if you wish.



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Aug 30, 2014
Don't forget the unloader
by: Bill

Ken, excellent post. Thanks much.

I do want to point out that unscrewing the line to the check valve unloads the air over the piston, and that trapped air is often a cause of air compressor not being able to restart once the tank air pressure is drawn down to cut in.

It's the compressor unloader valve that is supposed to open when the compressor stops, allowing the air in the line to the tank and over the piston to escape.

The check valve keeps the air in the tank so it doesn't bleed out.

If your air compressor starts too often, it could be that the check valve is not seating properly, allowing tank air to bleed out the unloader when it isn't supposed to.

Also, start capacitors do fail, frequently. When you say "easy to check with a quality meter", I chuckle, because lots of folks haven't a clue how to do that. So there's a page on this site explaining how to do that, too.

Further, I sure do like your site. A woodworker's dream store!


Aug 30, 2014
Kobalt 17 gallon trips wont start after tank is full
by: Ken

I have had the same problem with two Kobalt compressors. after much trial and error i found it to be the check valve. I replaced with a new one, but found the orifice in the release plug was not drilled correctly, so a new valve fixed the issue.

The actual issue is this...

when your compressor starts up, it'll run fine and shut off automatically when tank is 150 psi. when you use the stored air, the compressor struggles and quits because the 150 psi that is stored in the tank feed line is not escaping properly so there is too much head pressure for the motor to turn.

To verify this is the issue, just release the pressure in the feed line by slowly unscrewing the release bolt at the check valve. The motor should start right up again.

Its rare that it would be the capacitors, there are two, one for run and one for start and it gives it an extra boost on startup...easy to check with a quality meter, but if you do the check above, then the motor runs to fill the tank the first time, so its not the run capacitor, and if when you release the head pressure and it works then its probably not the start capacitor or it wouldn't start at all...

Quarter Oak Woodwork

Nov 29, 2013
Kobalt model #37296 Tries to start then trips breaker
by: Ron

Bill, The issues i'm having is with tthe tank completely drained.
OK, assuming that the compressor is plugged right into a socket, with no extension cord or power bar, the next thing I would suspect is the intake filter being plugged. If you remove the intake filter, does that make a difference?

It could also be the start capacitor that is weakening and it cannot give the circuit enough of a boost to get the compressor motor started.

See the page on checking the capacitors on this site.


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