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pressure valve leaking, pressure tank to be repressurized?

henriray Member Posts: 1
to the Expert...

I change 2 pressure valve they keep leaking on hydronic heating system mc lain boiler

I have the old type of pressure tank, I am told to re pressurized the tank with a pump

 The system should be at 12 psi cold  22psi when hot

Is this the correct way to approach the problem, what type of pump and hoe much psi shoud I have in the tank 22psi? or how many bar for this system

Thank you



  • billtwocase
    billtwocase Member Posts: 2,385
    "old type of pressure tank"

    Do you mean old style non-bladder type expansion tank? If you do, that needs to be fully drained of it's water, and refilled to 1/2 or less. Unless there is a hole up top, it will create it's own air space, and end up with about 15 lbs on the boiler. If the tank is full, and won't drain, you need to get air in there. There will either be a plug to remove, or a waste cap to loosen. The valve between the boiler and tank should be closed when draining. It would also be good to hire a pro to do this, and look into a bladder type tankfor the future
  • unclejohn
    unclejohn Member Posts: 1,803
    Sounds like

    You have replaced the relief valve twice. And it also sounds like you have a old expansion tank in the ceiling. The relief valve is opening because your expansion tank is water logged. Turn off the boiler. Shut the valve that goes to the tank and get a bucket and drain the tank. The drain is opposite where the water line connects. [it could take a long time to drain] Don't use a hose because you won't be able to get air into the tank and it won't drain. After its drained open the valve to the tank and you should hear water filling the tank and the system. If boiler is cold the pressure gauge should read around 12. If after all that its much higher or lower call a service guy and know you gave it your best shot.
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