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System Pressure Increase

Tom_45 Member Posts: 3
I recently re-piped my hydronic system following the "pumping away" guidelines, and am very satisfied that the air problem I experienced is now eliminated. Even thought the sytem was initially charged to 12 lbs when refilling it, I noticed that my system pressure is now at about 17-18 lbs.
I have a 3 zone (3 circulator pumps) system, one 1" diverter T loop, and two 3/4" fin tubes loops. The compression tank is a Watts ET-30. The boiler is a Weil McLain 117,000 btu/hr.
Is there a problem with the higher pressure? Or is there a problem that needs to be addressed?

Thansk, Tom


  • Does the boiler maintain temperature ?

    When the system is filled to 12 psi. cold , it will increase in pressure when it heats up . We see an increase like you had on just about every new install - 18 psi is the norm .

    By the way , where is the pressure reducer piped into the system ? Is it in the return to the boiler ?
  • Tom_45
    Tom_45 Member Posts: 3
    The boiler maintains temperature

    Yes, the boiler does maintain its temperature.
    When asking about the location of the "pressure reducer", do you mean the compression (or expansion) tank? Its on the supply side, before the pumps, downstream the boiler, just below the air separator. The make up water line is connected in just above the tank (controlled with a 12 lb valve).
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