compressor has leak coming from pressure switch.

by Rob
(Portage,Manitoba,Canada)

I recently bought a house with a 2 car garage/shop. The upright compressor had been functioning normally ( as far as I knew)because I had used it prior to buying the property.


Recently the compressor would kick on and stop only to have a hissing air from the pressure switch.

We had a guy come to the shop where i work to service the air compressor here. I asked him about my situation and to pop over to have a look at my setup.

Upon further examination he told me I needed a check valve. So i bought a check valve and he told me how to install it. I haven't installed it yet but my question to you is this:

The service guy told me that my compressor had no check valve installed and this would solve my problem. The kicker is that the compressor has been like that since it was hooked up by the last owners 'friend'

So how could it of run properly without a check valve before and now only just start to leak?

Should i install check valve to fix problem or would the problem be something else given the circumstances. Thanks for your time. Regards.
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Rob, typically, if the pressure switch is blowing air that is a symptom of a leaking check valve.

Since you do not identify the make or model of your air compressor, I cannot comment on the absent check valve issue, though it is certainly unusual for a compressor to hold air in the tank when the compressor is off, as it is the check valve that stops the tank air from bleeding off through the unloader valve when the unloader opens to atmosphere during the off phase of the compressor.

Normally, a check valve is installed at the tank port where the line from the pump head enters the tank.

Bill


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new switch where does white and black wires go

by jailhouse inc
(rhinelander wi)

bought a new condor mdr 11 need wiring info

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6.5HP - Air Compressor Pressure Switch Failure

by Curly
(Montana)

I need some help figuring out what's going on with my air compressor.

I have a 6.5HP, 80 compressor, relatively new. It works fine for general shop use, mainly for small air tools. But here's my problem.

When I use it to supply air to my Blast Cabinet and blast for say, 20 or 30 minutes, on two occasions the pressure switch has failed to turn the motor off and the pressure will rise in excess of 160 PSI and trips the pressure relief valve (kind of exciting!).

The switch actuator seems to work fine, its free to move. The switch is set to trip off at 120 PSI.
The switch is mounted on a small manifold attached to the top/side of the tank. Connected to this manifold is the balance of the ports that supply air to my Blast Cabinet.

So, I'm beginning to think that when I run the compressor for a long period ice will form in the line and block the line to the pressure switch.

I've seen this icing occur when I blow down the tank to change pipe fittings or lines. Ice forming is a normal process with a rapid drop in pressure. But I never thought it would block the pressure switch line.

What do you think? Have you experienced this problem? If so, what's the solution?
Thanks, Curly
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Well Curly, it is possible I suppose, yet based on what you've written, I'd tend to think that the pressure switch problem may be more heat related than ice blocking the line to the pressure switch.

The way to check, of course, is to run the compressor until the fault occurs, then be ready to pull the line to the pressure switch and try to blow through it to see if it's blocked. It would have to be a pretty solid blockage to stop the small amount of air that the pressure switch needs to work properly, from getting through.

Is your air compressor a 100% duty cycle? If not, I understand that you shouldn't run an air compressor for more that 15 minutes at a time without giving it at least that long between uses to cool.

I sure would be interested in hearing how this one works out.

Cheers,

Bill

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Can you identify this part?

by Steve
(Contoocook NH )



Seems to be a problem with this part little pin does not extend far enough to hit little flap that stops air from escaping. Can you tell my what this part is? It is located on the pressure switch and has a copper line attached to it. Picture included

_________________
Steve, see the Unloader Valve page for info about what this is, I believe, and what it is they do. Linked from site map page.

Cheers,

Bill

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compressor controls - pressure switches

by Joseph Rogers
(Leavenworth Kansas)

I have 2 champ. uprights that are set up to run tandem.
Many of our tools are cordless now and we don't need that much capacity anymore.
They are set up so #one cuts in @ 140 psi and #2 @ 100 psi.
I need to adjust the cut in on #2 so it also cuts in @ 140 psi
so we can run 1 pump at a time but let it use both tanks.
I read a description of the pressure sw. in another mssg.
but the only advice is always "don't change the adjustment".
I'd like to be able to switch daily from one pump to the other
so the # 1 pump isn't the only one doing all the work.
If we get a spurt where we're consuming alot of cfm (rotary
tools) by the time the # 2 pump starts the pressure out at the
tool has dropped enough to affect it's performance.

____________________
Bill says...

Joseph, there are two adjusting nuts inside typical pressure switches. Turning one adjusts the cut in, turning the other the cut out.

Follow the links from the Pressure Switch section on the site map page for more detailed info.

Cheers,

Bill



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compressers

by calvin
(ruckersville va US )

i couldnt find a pressure switch for my dayton air compresor soi bought one for a campbell housfeild same pounds of pressure rating will it serve the same purpose and i am adding a extra tank line should go from the compressor to the new tank out of the pressure switch

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Calvin, if you plumb the pressure switch properly - including the unloader valve, and it's got a similar cut in and cut out pressure setting as the old one, and it's the same voltage capacity, then press on! You can use any pressure switch that meets these criteria.

As to adding a tank, please visit the site map page and look under Tanks for more info. Lots there for you, chum.

Cheers,

Bill

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Sanborn compressor preasure switch will kick out @ 175

by David
(Wisconsin)

Bill
I am a 1st time caller if you may.

I have a Sanborn 60 Gallon compressor, it wants to keep running will not shut off.

when I came home from work the releaf valve was releasing air and it was still running, the points were stuck on the manual shut off, this has happened before, I filed them smoth but it did not help. So I replaced the switch. with a lefoo model LF10 4H .

first run on new switch it would not shut off @ 175 ran up to 200 psi and I cut the power off , tried to adjust cut off but no luck still ran psi up to 200 and kept running whats my problem
bad switch ?

Dave from WI
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Dave, gosh knows that the quality of the pressure switches that come with smaller air compressors isn't the greatest, but it's really bad luck to have two fail in a row the same way.

I wonder if you may have a power issue? By that, I mean power increases that weld the points together, or a short in the capacitor or motor circuit that is pulling too much power and frying the pressure switch.

What kind of power, what kind of fuse or breaker, and if you are up to doing it, maybe do a check and see the power draw on your compressor when it's running.

Keep us posted as a comment if you would.

Thanks,

Bill

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charge air pro - air pressure adjustment

by Kenney Boles
(Waterloo, SC)

I adjusted my pressure to cut off at 135 and on at 100.It is a charge air pro 5hp.I did it to make my sandblaster work.You think that's ok?
________________
Kenney, what was the original setting?

If you increased the cut out pressure above the original, I suspect you may do some damage, but I don't know how serious, as I do not know what the original cut in and cut out pressure levels were?

Can you post them as a comment here?

Cheers,

Bill

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