[Peter]

Peter,

After we spoke I checked mine. All 4 control valves are two wire valves as discussed. I don’t know why yours might be three wire.

But I did verify the operation which supports your theory that the pneumatic cylinder that actuates the gate valves is leaking. The normal system position is the air supply to the pneumatic cylinder is a normally open path through the control valve so the gate valve air cylinder always has pressure holding it closed. The path from the opposite air fitting back to the control valve is open. That is why you hear the leak. It is open so when the gate valve is being held closed by the air cylinder, the air on the other side of the air cylinder is exhausted.

When you command the gate valve to open, the control valve reverses the air flow. The supply line which was holding the air cylinder in the closed position now becomes the exhaust path and the exhaust line now becomes pressurized to open the gate valve.

I’m afraid for a permanent fix you have to replace the seals (probably O rings) in the air cylinder, but to do that you appear to have to remove the entire gate valve assembly, split the valve case by removing the half dozen screws and then remove and rebuild the air cylinder. The short term fix to keep you going until you have the opportunity to make the repair is to use the ball valve or thread a pipe plug into the control valve exhaust.

[Dick]

Thanks so much Jon the solenoid valve works now bad connector replaced it but still leaks air at cylinder , I think I will leave ball valve shut off until I can replace with new cylinder thanks so much