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BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22511
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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I have a Thermo Dynamics S-110 boiler and had to drain the

Customer Question

I have a Thermo Dynamics S-110 boiler and had to drain the system to make repairs on the radiator supply piping. I re-filled the system and now the boiler is running above 30 psi and causing the pressure relief valve (30 PSI) to open and leak water. When I filled the system I opened the valve on the expansion tank to bleed out the air. How do I lower the boiler pressure to the correct 30 psi?
Submitted: 1 year ago.
Category: HVAC
Expert:  BillyHvac replied 1 year ago.


did you remove the air from the expansion tank from the air stem?

Expert:  BillyHvac replied 1 year ago.

If you did you need to pump the tank back up...there is a bladder in the tank that expands and gives the water room to move....the relief is leaking because there is no buffer or expansion room. By removing the air in tank it just became a big pipe filled with water.

Pump the tank back to psi on label and you should be all set.