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Scale on Boiler

tms1989tms1989 Posts: 1Member
Hey all, I’ve noticing scale buildup lately on the outside of my boiler. Not sure what it is but it’s got me a bit worried. I attached a picture. Any response is appreciated!


  • Is this steam or hot water?
    It looks like moisture from somewhere has evaporated leaving behind calcium.
    When you can turn off the boiler for a day, you can try the overfilling test to see if there are any leaks, (steam).
    If it’s hot water, it may be condensation from the water being not hot enough, as a result of a faulty acquastat.—NBC
  • RayWohlfarthRayWohlfarth Posts: 660Member
    It looks like that is a water to water heat exchanger perhaps for domestic hot water? I think the flange may be leaking. I would brush it and try snugging the bolts a quarter turn and watch it. You may need a new gasket and it could be done in the summer.
    Ray Wohlfarth
    Boiler Lessons
    Click here to take Ray's class.
    Click here to buy Ray's books.
  • the_donutthe_donut Posts: 374Member
    I can’t tell for certain from that picture, but it looks like copper goes to steel without a dielectric union. That can cause corrosion from dissimilar metals.
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