Compressor stops before getting to limit of 150psi

by Tom
(Los Angeles)

I got a Porter Cable C2000-WK-1 air compressor that stops at around 145psi instead of the 150 that it was designed to stop at.


Then the pressure reading drops to around 135psi but holds the pressure. Is this a problem with the pressure switch control?

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Bill says...

Tom,sounds like it to me.

I'm puzzled as to why the pressure in the tank drops to 134 and stabilizes. It's almost as if the check valve leaks under higher pressure, but can hold at 135.

While you are checking / replacing your pressure switch, consider removing and cleaning the tank check valve too.

Good luck,

Bill

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Portor cable Pancke will not stop

by Daryl
(Hamilton Ontario)

I,m getting power right to that small thermal connector that is in line before the fuse . I believe the problem is that thermal looking connector.
thanks Daryl

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Bill says...

Hello Daryl. So your compressor won't stop? Hmmmm! Is it building pressure in the tank? Is the pressure building until it blows the PRV valve?

I do apologize, but I don't know what you mean by the "thermal looking connector"?

Gosh, maybe you can send in a photo, because I'm just not getting it.

Often, when a compressor continues running past the normal cut out pressure, the problem is the shut-off / cut out part of the pressure switch function has failed. That being the case, replacing the pressure switch is the solution.

Cheers,

Bill

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Compressor won't kick back on

by David Davis
(oak hill wv)

Compressor falls below the kick on point and when tries to kick on just sits and hums If you bleed the tank down between 20 and 30 pounds it will kick on when you flip the switch and build pressure. Sears craftsman Model # 919.152940

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Bill says...

The "sit there and hums" suggests to me that the unit can't start either because the start capacitor isn't providing a boost, or that it is, but the compressor can't start against load.

When you bleed the air pressure down, you may be lessening the re-start load, which suggests to me that your compressor isn't unloading when it reaches cut out pressure.

Bleed the air down to the point where it will start, and listen near the pressure switch / unloader valve to hear if it dumps air when the pressure cuts out. If it doesn't, the unloader valve needs looking at.

If it does, then it might be your capacitor.

Cheers,

Bill

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motor runs but cuts out?

by pete van noie
(de pere, wi. usa)

i had the motor checked out and theres nothing wrong with it? the motor starts just fine and runs the compressor for a short time and then the breaker kicks out? is there a relief valve on the compressor thats not working?

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Bill says...

What turns the compressor on and off is the pressure switch.

If the compressor turns on properly at the cut in pressure point, but shuts off before the pressure in the tank reaches the high pressure cut out, then I would suspect that the pressure switch is pooched.

Since it's among the least expensive things to replace, I'd start with that if it was me.

Cheers,

Bill

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Compressor shuts off when redlines....

by Robert
(Hampstead, NH)

I have a 5.5 HP 8 Gallon Gas Titan Industrial Compressor that starts to build pressure, but when the pressure gauge gets to 125 psi, or the redline, the motor cuts out. I have been told multiple things, I was wondering what your thoughts were?

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Bill says...

Hi Robert. What is the normal high pressure cut out for your compressor?

It might be that it's 125 PSI, and if the motor stops there, then it's supposed to.

If the compressor cuts out at 125 PSI and it normally cuts out at, say, 135 PSI, then I would suggest that your pressure switch is failing.

Cheers,

Bill

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Intermittantly Builds Pressure

by Longsurfer
(Florida)

My 2003 25 Gallon Husky runs for a half a minute building pressure, then cuts off. It'll automatically start back up in about a half minute and continue to build from where it left off. Any suggestions on trouble shooting the motor or switches?

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Bill says...

Since it's the pressure switch that controls the start and stop of the compressor motor, it would appear to me as though the high pressure side of the switch is failing.

Once the motor starts, unless it has a bad connection to the power supply, what keeps it running is power coming through the switch.

If the high pressure cut out is wonky, it may be alternatively acting as if the cut out pressure is reached, shutting the motor off, and then the absence of the high pressure air signal closes the points again.

That's what it seems like to me.

Cheers,

Bill

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Jul 10, 2010
Pressure Switch or Motor
by: Longboarder

Seems reasonable . . . the other idea was that the motor was overheating and tripping off then back on . . . could it be doing that in under a minute? If so, is there a motor trouble shooting that can be done to rule it out?

Thanks for the help,

Longboarder

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AIr Compressor Does Not Auto Shut off!?!?

by Jordan
(Mich)

I have already replaced the switch assembly, and still nothing it still keeps running and running... eventually when i see the pressur getting extremley high i shut the unit off. Then when i go to turn it on it wont because the air pressur is too high. Then i bleed some air out and i can turn it back on any ideas?

Husky WL 30 gallon compressor

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Bill says...

Jordan, either your new pressure switch has failed too, or it has been wired incorrectly so that power flows to the motor and bypasses the switch.

What you shut it off, if you aren't toggling the pressure switch manually, then the pressure switch, in turn, is not toggling the unloader valve, which is why it won't restart until you bleed pressure.

You have a switch issue of some kind, I think.

Cheers and good luck,

Bill

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Air Compressor won't stop

by Andrew Mambari (Mr.)
(papua New Guinea)

after the air compressor is fully loaded to cut-out setpoint, it continues loading and the motor amps increases greatly; e.g. from 92A (at cut-out) to 115-120A (when continuing loading).
What are some of the failures that I can fix??

Your kind assistance will be aprpreciated greatly...

Regards...//Andrew
Email: a.mambari@pngtaiheiyo.com.pg

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Bill says...

Andrew, it makes sense that the amp load increases, as the compressor has to work harder and harder to compress air against the pressure already in the tank.

What shuts off your compressor is the pressure switch. Have a look at the pages on this site providing info on this important part of safe compressor operation. I think you need a new one.

Cheers,

Bill

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hitachi air compressor wont start at all (pressure switch)

by chido chido
(Vista, California)

Hi i have a hitachi air compressor it wouldn't start one day and i realize there was something wrong with the power cord.

i replaced it and it worked fine for a day the next time it started up again and seconds later it shut off. i empty the tanks and did all the routine check. my last resource was to by pass the pressure switch, and it worked, so i want to know if there is any way to adjust the switch or what can i do before i decide to replace the switch. i looked at the inside of the switch and looks clean there's no burned marks or damaged indicating a short or signs of overheating wires.

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Bill says...

If you bypass the switch with power and the compressor runs properly (except shutting off, of course) and you re-wire through the switch and the compressor won't run, then you have completed a fine diagnostic. It's the pressure switch!

You can tamper with trying to fix them, but my experience suggests that it's a lot less time and hassle to take the switch to the compressor store, and find one to match.

Make sure the new one has close to the same cut in and cut out pressure levels, and that the new switch will interface with your unloader valve properly, once it's installed.

Cheers,

Bill

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my 2 stage compressor hit the cut out-165psi then shut down and tries to restart thus blowinf the breaker

by greg
(granite falls,wa)

its an westinghouse v-twin 2 stage with a remote 80 gal tank. check valve or pop off mounted to the tank with a 1/4 copper line running back to the pressure switch, 220 volt on a 20amp breaker 16 amp draw from the motor. switch says cut in at 145 with cut out at 175 needs to be adjusted I know but seems it should shut off with out trying to restart 10 seconds after shutdown. Compressor is a westinghouse model 2VC-1 any diagraghms on plumbing this thing-- on the inlet side,tank to pressure switch etc e-mail me at gregvan2008@myway.com thanks hope you can help

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Bill says...

Greg, I hope someone reading this has the diagrams or schematics you are looking for.

If your compressor is trying to start 10 seconds after reaching cut out pressure, and assuming that the tank pressure is still above the cut in pressure setting, then I would suspect your pressure switch is at fault, unless something in the line is preventing the tank pressure from registering on the pressure switch diaphragm.

If the compressor stops at the cut out pressure point, does it unload? You should be able to hear it. If it doesn't, and it tries to start against pressure over the piston(s), that's likely why it it is blowing the breaker on attempt-to-start.

Cheers,

Bill

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May 20, 2010
cut out
by: Anonymous

thanks bill I think you are right its nopt unloading and that is part of the problem -gonna replace the switch and do a bit of plumbing re-work

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