harbor freight compressor thermal switch keeps popping out

by scott
(new jersey)

i have the 90234 air compressor from harbor freight. i have used it quite often for over a year. i have even pushed it multiple occasions running it nonstop for hours without a break.

yesterday while using it with my sandblaster the thermal switch popped and the compressor died.

i restarted it to only have it run for about thirty secounds before it died again.

figuring it needed a rest i left it alone. today i went to start the compressor only to have it run for another thirty or so secounds and just cut out, it didn't even fill the tank.

the oil and its level seemed fine.

is it possible my motor is dying. i have it on a power strip all by itself connected to an outlet without anything else and i never had this probem before even when running the compressor for hours at a time.

i am going to check tommorow if ther is a restriction of some sort in the copper line. if i can get any advice i appreciate it. thanks

Bill says....

Scott, I don't know what the Duty Cycle of your model of Harbor Freight compressor is. If you are not sure what I mean by Duty Cycle, see the link from the site map page.

I think, reading between the lines, that you know that you have abused the compressor. If, in fact, it is not a continuous duty compressor, from your own admission, you have run it long and hot, and I suspect, this has damaged your motor.

Sounds like you have had your money out of this one, and since, I suspect, that replacing the motor may only solve on of the issues, it may be time to retire this one for parts, and get another.

To be sure, find an electric motor rebuild shop, and take the motor there for a load test.

Cheers and good luck.


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Harbor Freight 65903-2VGA runs for 20 seconds and then trips

I have read all relevant posts and I kind of have the idea that it is my motor..

I have a secure connection to the wall with no extension cords and I hired an electrician to install the proper source.

Out of the box the compressor built pressure for 20 seconds and then tripped its breaker. I press the reset button and it works for 20 more seconds or so. Technically, if I wanted I could do that over and over until I acquired proper pressure, but something tells me that that is a bad idea.

If I install a new motor on it (which I am capable of doing, I think) which one should I get? And how am I certain that the pressure switch and breaker are connected properly?

Before I buy a new motor though, could it be the check valve or pressure switch malfunctioning? After all, those are quite a bit cheaper... and for a cheapo compressor in the first place, what a pain...

Thanks, Johnny

Bill says....

Hello Johnny, and thanks for writing in.

If you have to push the reset, and that reset is connected or on your electric motor, then it sounds as though the motor is going off on thermal overload. Does the motor get really hot?

You are right, a pressure switch is cheaper than changing the motor. You might want to replace that just in case. Worst case scenario is, if that doesn't solve the problem, you'll have a spare pressure switch for somewhen else.

Under the lid of your pressure switch, you should see a wiring diagram. Use that, and, do what I do... take a digital photo of the pressure switch before your remove a wire so you know which goes where when you replace it. Make sure you disconnect the power and dump the air.



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