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Pressure excedance ??

I just recently bought a house with a water boiler heating system. In turning it on it seems to be working OK but the pressure gauge on the system is pegging out at 30+. With the system off, the gauge reads around 12 psi. A couple of questions......
1) Am I in danger of blowing the system or does the relief valve give me the needed safety factor.
2) With the system off, should it maintain the 12 psi head pressure ?? I am assuming a non-functioning pressure gauge.

Thanx All


  • SWEI
    SWEI Member Posts: 7,356
    Is a tankless coil or indirect hot water heater connected to the boiler?
  • Tinman
    Tinman Member Posts: 2,808
    At 30+ is your relief valve opening? If it's rated at 30, and most of them are, it should be opening at 30.
    Steve Minnich
  • Zman
    Zman Member Posts: 7,573
    Problems like this are often a result of a failed or improperly set up expansion tank.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • rodjburge
    rodjburge Member Posts: 2
    Response to the above inputs.......
    Not sure that I know the diff between tankless and indirect. The system is one unit that has a pilot/burner. It is obviously coming on and heating the water that appears to be contained in a tank with the pipes for the flow running through out the house.
    There is not relief valve opening. If it wasn't for seeing the gauge pegged I would assume that all is running properly.
    JUGHNE Member Posts: 11,076
    Do you have a separate water heater for your faucet hot water?

    If your heating boiler is at 12 PSI when cool and rises quickly when the heat comes on, then you have no air in your expansion tank and should not use the heating boiler until you get it fixed. The relief valve may be stuck or someone may have put a plug in it because it was dripping.

    Post some pictures of your boiler and any tank attached to it.
    You mentioned a pilot light, if your system is older it may have a tank hanging above it at the ceiling. DO NOT continue to use this until you get it fixed. Someone here may help you if we have pictures.
  • BobC
    BobC Member Posts: 5,479
    It may just be a wonky gauge but you should have it looked at NOW.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge