SpeedAire Direct Drive compressor slow air leak

by John Wilcox
(Minnesota)

I can hear it below the tank pressure gauges but can't find the source.


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Bill says...

Could the air be leaking out your unloader valve, John?

Check the unloader page linked from the valve pages to better understand why an unloader valve might leak when the compressor is stopped.

You might also check out the check valve pages as well.

Cheers,

Bill

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How to stop air air leak from the compressor..

by marci
(Victoria BC Canada)

My air compressor is set at 80 psi. It pumps to this setting and as soon as it shuts off you can hear a leak from a valve at the back.

Then the pressure drops quickly which causes the compressor to recharge. Do you think an o ring has gone?

You can feel the air coming out only when it has stopped pumping. The escaping air is from sort of screw attachment to a valve on the top at the back of the tank. Can you tell me why? How do I fix?






Bill answers...

Hi Marci. Welcome to you and other folks from Victoria.

It's hard to be sure without seeing it, but I suspect that "the valve at the back" is the unloader valve for your compressor.

It's supposed to open when the compressor stops to "unload" the air that's compressed over the piston.

So, when your compressor reaches the high pressure cut-out, the unloader valve opens, you hear that characteristic "psssshhhhtttt", and then the air stops.

Only, in your case, it's not stopping.

That tells me that the air (again, assuming that it's the unloader valve that the air is leaking from) is bleeding back out of your tank, up the air line to the unloader valve, and out to atmosphere.

When your compressor is compressing air, it's pushing that air down into the tank through a one-way valve (also known as a check valve). That valve is supposed to keep the air in the tank when your unloader valve opens.

I think that either your check valve has a worn seat, or there is debris that's preventing it from closing tightly, and that's where the air is coming from.

If you are up to it, make sure the tank is empty and the compressor is unplugged, and look for where the air line from the compressor head goes into the tank. There should be a check valve assembly there. Dismantle it, make sure that the internal valve flapper or ball is seating cleanly, reassemble and test.

If I'm right, this should solve your problem.

Why not let us know how it turns out?

Cheers,

Bill



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Charge Air Pro unloader leaking

I have a old Charge air pro compressor by Ingersoll-Rand with a 5 hp 240V motor.

The factory installed telemecanigue pressure switch went bad. i replaced it with a Condor 3FWF9 grainger item number pressure switch. www.grainger.com

Once the compressor starts building pressure air flows out the unloader valve at a high steady rate.

If i turn the compressor off the check valve closes and air stops leaking. once i turn the compressor back on, air again purges.

The problem seems to be completly backwards. I understand that once the tank pressure builds there should be a burst to relief head pressure.

My compressor just bypasses until power is removed and then the tank holds pressure. I thought i had a faulty part so the store sent me a replacement. Both switch have the same issue. I'm lost! Thanks for the help.

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Is it possible that the toggle for the unloader valve is reversed on the new switch so that it is opening when it should be closed and vice-versa?

Cheers,

Bill

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photo of valve bypass port connection

by bill wuttke
(cambs england)


if i can download a photo i would like to know where the bypass port is connected to , one port is inlet, other outlet and the bottom says bypass but i dont know where to connect or what it does regards bill

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Bill, I recall you sent in another post, but the details evade me.

Where, on your air compressor, did this part come from?

Please post your response here so I can check the thread entirely.

It looks like it might be part of your regulator, but I can't tell from the photo.

Cheers,

Bill

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kellogg american 331tva unloader bleeds during operation

bleed off valve continues to off bleeds during operation

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If by bleed off valve you mean unloader valve, it is supposed to be shut while the compressor is running.

If air is leaking out of the unloader during operation of the compressor, the unloader probably needs repair.

Cheers,

Bill

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Compressor will only fill tank once / air leaking out

by Michael Accardi
(Henderson, NV)

I have a Craftsman oiless 60 gallon compressor with issues. If the compressor is empty, the motor will turn on and start filling the tank. However, the regulator has some type of valve on the side that lets air out. The regulator is set to start at 140 psi and stop at 160 psi. The compressor will reach 160 psi and shut off, however, the little air valve on the side of the compressor keeps leeking air until the tank pressure reduces to 140 psi. Once the tank is at 140 psi the air stops leaking from the regulator, the motor tries to restart, makes a humming noise, and blows the breaker. I removed the cover over the pump and can hear an air leak from the what I believe is the high pressure side piston. I also try to manually move the wheel to cylcle the pistons, however it won't move. Once the tank is back to 0 psi I reset the breaker, the motor starts right up and the compressor once again fills to 160 psi, however, the problems I mentioned above start all over.

I replaced the regulator and both head gaskets. I don't know what else to do. The craftsman manual specifies certain torque for the screws that hold the heads onto the pump. I don't have a torque wrench so I just tightned the screws down good. Could I have tightened to hard and blown the head gasket again? Any ideas would help I'm getting very frustrated. Thanks in advance for any help you can offer!

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Bill says...

Hi Michael. You may have a number of problems, or just one that is manifesting itself in various ways.

So, lets get the obvious out of the way.

When the motor is off, the small valve that is leaking is, I believe, your unloader valve. When the motor stops on high pressure cut out, this valve opens to allow pressure over the piston to relieve, making restart within the power parameters of the motor and circuit.

If air continues to come out, you likely have a check valve leak. Go to the Valve page, and click the Check Valve link, read the page, and make sure first that your check valve isn't the problem.

If it was leaking and it solves your problem... good! If ensuring that the check valve is not leaking doesn't, post a comment on this thread telling me what you found and we'll move on to the next step. Make sure you add it to this thread so I can go back and review.

Cheers,

Bill



Comments for Compressor will only fill tank once / air leaking out

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Nov 02, 2010
It's fixed
by: Anonymous

Bill, thanks for your reply and having this excellent website as a resource for the public. I think I was a little premature on posting the question since after I posted it I dug around a little more on your website and found a great deal of information that helped me solve the problem.

Basically, when I changed out the head gaskets I noticed that one of the head gaskets was missing a little piece. The last part of the compressor that I checked was the check valve. When I checked the check valve I found that the little piece of head gasket that was missing was lodged in the head valve and not allowing it to work properly. I removed the blockage in the check valve, reassembled everything, and the compressor works great now.

Thanks again for your help!!!!

Mike

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Glad to be of help.

B.

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Air compressor fills then shuts off as normal then tank starts to empty

by Doug
(Canada)

air tank fills to 125 as normal then shuts off presure release stars to empty the tank. The swich with the wire pull ring on it. What couses this Thanks.

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Bill says...

Hey Doug.

On the side of the pressure switch, there's a little valve that is toggled by the pressure switch shifting. Is the air bleeding out the end of this valve? If so, go to the Valve page and click the link to the Check Valve page.

If it is the valve with the ring on the end, that is, I think, since I can't see your compressor, the PRV or pressure relief valve. Pull the ring on it, and then push it back in. Does the air flow stop?

Post your response here in this thread as a comment, please.

Bill

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My compressor has. a problem

One day it just stopped building up pressure. It's loseing air beneath the automatic control mechenism that's located next to the guages. What's the problem and how can it be fixed? It's brand is Central Pneumatic Model 90234.

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Bill says...

Hi there...

Go to the valve page, and click the link to the check valve page. Have a read.

From the sounds of it, your check valve is leaking.

If what you read makes sense to you as the cause of the problem, dump all the air, unplug the compressor, remove and inspect, clean, or replace the check valve.

Cheers,

Bill

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