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Help! Ok to turn off water main with a boiler?

Sera Member Posts: 5
Hey guys, We just had a leaky hot water heater and had to shut off the water main. Only problem is that we have a boiler. Is it ok to turn off the water main for the night (until we can get help fixing the hot water heater.) Or will this damage the boiler? It is a "Gas-fired, Natrual Draft Hot Water Boilers, sizes 37,500 thru 280,000 series A" BW1 or BW2 (not sure which and that is all the info on the manual). It's not that cold but is definitely 20 or so and I am concerned about damaging the boiler and costing myself tons of money!


  • Gary Smith
    Gary Smith Member Posts: 400
    You should be ok turning off the main. Hot water boilers rarely need to have any water added.
    HVACNUT Member Posts: 4,540
    There should be a cold water shut off valve at the tank at least.
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,660
    Shut off the main, cut the supply to the water heater, put a shark bite on it, turn the main back on.
  • sunlight33
    sunlight33 Member Posts: 376
    See if you can find a valve going into the inlet of the tank.
  • Intplm.
    Intplm. Member Posts: 1,374
    There is A isolation valve commonly installed on the cold water pipe supplying your water heater. Turn that valve off. If there is a shut off on the hot water supply then go ahead and close that one too.If not . Thats ok. Then go back and turn the water main to the house back on.

  • Intplm.
    Intplm. Member Posts: 1,374
    Also...........If this is a gas water heater. Turn the gas off to the water heater at the gas valve suppling the water heater as well as the water supply. If it is electric. Turn the electric off at the breaker panel.
  • Intplm.
    Intplm. Member Posts: 1,374
    This will isolate the water heater and you can continue to heat the house.
    EBEBRATT-Ed Member Posts: 11,895
    If you can't isolate the water heater and can't turn the water back on check the water pressure in the boiler there should be a gage on the boiler.

    The boiler pressure should be between 10-25 psi depending on the water temp. 12-15 psi is ideal.

    If your between 10-25 your ok for the night. Shut the water off going into the boiler water feeder. Probably a small 1/2 copper pipe