Problem with Coleman Powermate Air Compressor

ctb1980 · Jun 13, 2015

I have a Coleman Powermate 6-1/2 horsepower air compressor. I have always left it turned on all the time so that I would have air available whenever needed. A few times now, including twice in the last week now, I have came into the shop and found the compressor running continuous. When I have found it running, it appears that the relief valve has opened and it is blowing out of that. So today I decided that the pressure switch must not have shut it off and the pressure got too high and blew the relief valve, but the relief valve stayed open so the compressor never shut off. But I also wonder if the relief valve popped open prematurely and stayed open leaving the compressor running. So now I am wondering which do I replace, the relief valve or the pressure switch? What do you guys think?

MarkB_MI · Jun 13, 2015

If you can adjust the switch, turn it down a few psi.

Steve@Advance · Jun 13, 2015

You'll need a reliable gauge.

If you can catch it when the pop off first blows, quickly look at the pressure, see if it's above the safety valve setting. The safety valve setting should be marked. If it's going off too soon, the safety is bad.

If the pressure is going over the safety limit, try turning the pressure switch down. But if this is something that has started on it's own, the pressure switch is probably going bad.

Gary from Muleshoe · Jun 13, 2015

I have a Craftsman that had that same problem once. I just sprayed WD40 on pressure switch and the problem went away. That was 5 years ago, haven't had a problem since. .

Bob · Jun 13, 2015

And flip the breaker that powers the *&^*%^ thing when you leave.

If there are no leaks, the tank will still be up to pressure when you return.

I built my shop in '83 and bought an 80 gallon 2-stage compressor the next year.

With a little maintenance, it's still working well.

I shut the breaker off every time I leave the shop and flip it back on when I return, Only RARELY goes the compressor start 'cuz I try to keep the system leak-free.

Russ from MN · Jun 14, 2015

I have indicator lights on both my compressors and very rarely leave them plugged in, I always leave them pressurized, one will hold air for months.

paul · Jun 15, 2015

As i age and run into more and more goofy things happening, I get more and more conservative on such things. Don't like to leave stuff on any more, as others say, let the tank fill and shut it off, should hold most pressure for days, and flip it on will be right up if you need air.....

Probably need to stick around and catch the thing in the act of blowing off to figure out if it is over pressuring or popping early.

Paul

jimg.allentown · Jun 16, 2015

The pressure switch _should_ turn off the compressor before the safety valve pops off. The safety valve should "reset" when the pressure drops down. The levels and pressures are somewhat built in to the system. The pressure switch is somewhat adjustable, but the safety valve is usually not. As previously stated, you would need to catch it malfunctioning to get a handle on which part is causing the problem. Pressure switches do get unreliable when they get old. Safety valves may also get funny in their "old age" so to speak. For future reliability, I would consider replacing both parts.

Problem with Coleman Powermate Air Compressor

ctb1980

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MarkB_MI

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Steve@Advance

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Gary from Muleshoe

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Bob

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Russ from MN

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paul

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jimg.allentown

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