Air leaking from inter stage safety valve

by Muhammad Imran
(Pakistan)

Hi there!


I have a Gentilin air compressor C330/20 which is malfunctioning due to air leaking from inter stage safety valve and thereby compressor getting heat up. For this reason air pipe which is supplying air to PRV broken and one of 60 micro fared capcitor also blown. This PRV is the part of pressure switch. Air leaking stops when air pressure inside the cylinders reach at cutout point.

I have replaced Check Valve, Pressure Switch with safety valve and also polished both reed valves because they were rusted. During opening one of gasket of reed valves was also damaged but now it is replaced.

Furthermore I also exchanged the seat/ fitting of NRV but problem is still there.

Please be so kind and help me regarding this issue.

Thanks in advance for your support.

Regards,

Imran
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Imran, if this problem is in a line between two cylinders, then typically, the issue is with the intake valve on the downstream side of the PRV.

If that valve is creating a blockage, then the pressure in the line increases beyond the normal level, and the PRV lets go.

Bill

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Sep 21, 2013
Air leaking from safety valve
by: Anonymous

Dear Bill,

The air intake valves, I assume that are the HP and LP reed valves, Am I correct?
If so, then Reed valves were rusted but Now I've remove rust with WD-40 and with abrasive paper so it seems to be O.K.

I've two air compressor, but since Wednesday the 2nd compressor also have the same air leaking problem.

Let suppose there is a blockage in the air intake or reed valve, what is the remedy or how can i fix it. Right now I've no inventory available regarding the air compressor. Is it possible to repair it?

Thanks in advance for your support!

Regards,

Imran
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Howdy again. If the PRV blow off problem is in a line between two cylinders, then typically, the issue is with the air flow into the second cylinder.

I don't have access to this brand of air compressor, so I cannot even see how yours is configured.

On a two stage air compressor, air flows from the first cylinder in a pre-compressed state, and then enters the second cylinder to be compressed further and driven down into the tank.

There is a PRV between the two cylinders to deal with the issue of some sort of blockage in the second cylinder that prevents air from the first flowing onward. The air paths are relatively small, and if the first cylinder keeps driving air towards the second cylinder, but that air cannot move on, then an overpressure will occur very quickly, hence the need for a PRV.

Something is, I think, blocking the air flow from the first cylinder through the second and down into the tank.

If not the valves, then, perhaps, the tank check valve?

B.

Sep 20, 2013
Air leaking from safety valve
by: Anonymous

I have a problem of air leaking from safety valve. During pumping air leaking and compressor running continually and trying to fill up the tanks until the desire pressure or cut out point (10bar) has reached. But it won't reached at cut out point because of air leaking, so it continually pumping and as the result air line and piston head are getting hot enough to burn if touched.

Regards,
Imran
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Hi Imran... did you check the intake valve on the second cylinder, as noted in response to your original post?

Bill

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3 Stages Compressor PRV blowing off

by Garnet

The 2nd stage of my 3 stages air compressor is blowing off. what could be the prolem here.

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Bill says...

Garnet, pretty hard to even guess with the scarcity of info.

Do you know the pressure that this PRV is set at, and is it blowing at that pressure? If so, then you have an overpressure developing.

If it's letting go sooner than it's supposed to, then the PRV itself may be at fault.

Bill

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SPERRE HV1/140 compressor PRV blows off?

by Edwin
(germany)

SPERRE HV1/140 compressor Photo: http://www.sperre.com/

SPERRE HV1/140 compressor Photo: http://www.sperre.com/

hi bill,

i have a problem with my newly overhauled air compressor. brand SPERRE HV1/140 water cooled, two staged , accrding to manual safety valve or PRV blows off when there is a restriction going to the 2nd stage valve or high pressure valve, i changed new safety valve and changed new complete valve both stages but still i have same problem blows air on the safety valve after 1st stage before going to 2nd stage.........hoping for your immediate answer thanks in advance and more power


edwin
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Edwin, if the PRV between cylinders is blowing off, then you have some sort of restriction slowing the air moving from the first to the second cylinder. This is backpressuring the line, the pressure builds and the PRV lets go.

Typically that's an intake valve or pressure valve on the second cylinder, but it could also be a failing tank check valve.

However, I've had absolutely no experience with your brand of compressor. I hope that someone with a SPERRE HV1/140 model can help.

Cheers,

Bill

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worn out in-tank PRV bypass?

by Steve
(Bozeman, Montana)

I have a large 10 hp/150 gal. tank Speedaire compressor and the in-tank pressure release valve is shop.

I cannot get a replacement for 7 days and I have some contract deadlines to meet.

As each of the heads has it's on PRV and the pressure gauge on the top of the tank has it's own PRV, can I take the in-tank PRV off and connect the braided line from the jugs directly into the tank without creating a dangerous situation ?

It might be only for a day or so of spraying but every day of sanding and I don't need a bad sitution but this solution seems ok. What do you think ? thanks, Steve

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Bill says...

Steve, I sure understand the dilemma.

I am not in a position to over-ride the design engineers of your compressor. If the tank PRV was not necessary, I assure you that they would not have designed it in.

If the pressure switch high pressure cut out fails, then it's the PRV that will save you from potential disaster.

If you do it, you run the risk. I cannot advise you to do so.

Bill

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prv leaking

by George
(Eastanollee GA , USA)

Every new PRV I have installed on my air compressor leaks air. It starts to leak just before set point and then wont stop till it drops 20-30 PSI, why?
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George, if they all (how many?) the PRV's you have put on your air compressor leaks air (that means it blows off) just before your air compressor reaches the set point to cut out, then your PRV's are at too low a setting.

While you cannot adjust the basic PRV, you can acquire ones that blow off at a pressure level that is higher than the cut out of the pressure switch.

When you go to get the next one, ask about the pressure settings of the blow off on the new PRV.

On the other hand, PRV's typically are not spring loaded, and if yours is shutting off when the pressure drops by 20-30 PSI, I have to wonder if we are really talking about a PRV at all?

Comments here are welcome. If you do, you might let us know the make and model of your air compressor. That might help.

Bill

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Jul 08, 2013
PRV
by: George

I have replaced the PRV 3 times. The third one came from the manufacturer. It was made for my particular model. The compressor is rated for 125 PSI should I use a higher rated PRV, one perhaps set for 150 PSI.
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If this were my compressor, and the normal cut out was 125 PSI, then I would have no problem installing a PRV with a release point of 150 PSI.

B.

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Curtis E57 compressor relief valve pops

by henry Mastalski
(Fleming Island Fl)

the pressure relief vavle on the head of my curtis e57 compressor pops off when full pressure is reached. it will continue for a short time, the factory tells me that the relief is set at 70 lbs. it has not been tampered with. the valve springs were replaced at an authorized dealer the gave me no answer to the problem.
Thanks for any info. Henry

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Bill says....

Henry, the PRV lets go because it is experiencing pressure in excess of it's set point, or it is failing. I can think of no other reason.

I ask the many knowledgeable readers of this site for what conditions on your air compressor could cause this to happen.

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Nov 24, 2011
curtis e57 relief valve popoff
by: Anonymous

I resolve the rv poping problem. The o ring on the second unloader valve was bad. Henry

________________

Thank you for the update, Henry.

B.

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