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  • Black tank air valve

    Posted by Peter on October 4, 2014 at 10:12 am

    Well here’s a update about the air leak in the water bay , I replaced the solenoid valve it still was exhausting air , I think it’s the air ram for the knife valve for the black tank , it was new in April has anybody repaired one or replaced it???

    i pulled off bottom hose on air valve and it was pushing out air from ram , I think it’s the o rings inside that ram any thoughts!!!!!!

    I did put some air tool oil in ram thought that might help but did not

    Peter replied 11 years, 11 months ago 2 Members · 2 Replies
  • 2 Replies
  • Peter

    Member
    October 4, 2014 at 1:31 pm

    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

    Member
    October 4, 2014 at 3:49 pm

    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

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