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water boiling in cast iron boiler

has any one ever had this problem if aquastat bad?


  • shawnnolan
    shawnnolan Member Posts: 7
    do you have a tridicator installed what is it reading? sounds like your aquastat is overshooting, what is your boiler pressure?
  • but it is possible?
  • icesailor
    icesailor Member Posts: 7,265
    edited December 2014
    Of course it is possible. It happens often. If the water sounds like it is boiling, and the tridicator gauge is reading something that is much higher than the high limit setting, the limit control is bad.

    They're not that expensive.

    Why all new boilers should have a manual re-set additional High Limit control.
  • John Mills_5
    John Mills_5 Member Posts: 946
    Then there was Dad and the family home. National US Boiler from the 50s, hot water on an old converted gravity system. One day the old beast starts banging up a storm and was steaming hot. Even though he barely knew which end of a screwdriver to hold, he managed to figure out something was wrong and shut the gas off. The gas valve stuck open. Got the valve replaced and a year later she split open. Apparently didn't like getting that hot.
  • icesailor
    icesailor Member Posts: 7,265
    They are designed to run hot. Especially those old National US Boilers. They don't live forever.