Sanborn air compressor will not turn on

by Don
(Lockport IL)

I have a Sanborn air compressor 60 gal in the garage hard wired to sub panel in garage. Now it has been extremely cold here in Illinois. My garage is not heated but insulated. I don’t use compressor every day.

I had it wired with an on off switch basically a light switch.

I used it recently and after normal operation the safety valve popped and unit wouldn’t shut off at cut off.

The unit has a Furnas model 69JF7LY2C pressure switch. I tried adjusting set screws and did nothing.

Now to 2 days ago same issue while working on my truck.

I also had a buddy welding in the garage which popped a breaker for that outlet.

So I reset all breakers and now compressor won’t even turn on???

Where do I start to diagnose the issue? Is switch bad, does cold have a factor. is it on the power side?

Please help Thanks!!

Don
_______________

Don, if the air compressor will not shut off at the normal cut out pressure, but continues to run until the PRV lets go, that’s almost always a problem with the pressure switch itself.

Since, in my opinion, this is the most critical issue with those on your Sanborn air compressor, I suggest you replace the pressure switch immediately.

Yes, cold does affect the starting of an air compressor. That’s referred in a page in the troubleshooting section.

If your 60 gallon Sanborn is a 5 HP, 240 volt compressor, and it were mine, I would not power it through a typical on/off switch. I’d get an industrial, heavy duty switch. But that’s just me.

If you were welding and using compressed air, and the power for both pieces of equipment was on the same circuit, I expect you exceeded the amperage draw of the circuit.

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