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Help--cast aluminum heat exchanger is leaking through two pin ho

Sawyer Member Posts: 3
My son just called a few minutes ago and said his Utica ub90-200 natural gas boiler with a cast aluminum heat exchanger is leaking through two pin holes. I would like to get some possible directions to help him with this problem. I am driving to his house today and will check responses along the way when possible to get an internet connection.

Does this mean that the boiler is trash?
Is it cost effective to replace the heat exchanger or is it usually best to replace the whole boiler?
Can it be repaired by welding or another method?
Do any of the liquid weld patches work? If so which ones, even if only a non-permanent short term repair to buy him some time to find a good permanent solution.
It is a 2005 model and possibly would have a part only warranty coverage.

Thanks, George


  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    Is the leak on the inside (pressurized heating water) or...

    is it condensate leaking out. If it is the latter, the use of ProPoxy or some similar 2 part putty type epoxy will provide a temporary patch.

    Although possible to have a leak on the water side, it is more than likely that it is a condensate leak, which is non pressurized.

    EDIT: If it has an improper antifreeze in it, it could be leaking on the water side...

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • joel_19
    joel_19 Member Posts: 931

    I would think it would be under warranty for the part but not labor. Boiler stop leak does work well on cast iron pin holes not sure about aluminum. Should be available at any local boiler supply shop.
    Just reinforces in my mind why i only sell the stainless ones.
  • joel_19
    joel_19 Member Posts: 931

    If Mark is correct about the leak point epoxy should patch it. Here we have Devcon not sure if it is available everywhere great stuff have used it to repair radiator sections and it's lasted for years.
  • Sawyer
    Sawyer Member Posts: 3

    Thanks All,

    I will check to see if condensate or water when I get to his house. I have enclosed photos of the location.
  • Sawyer
    Sawyer Member Posts: 3

    Thanks again for the help. Unfortunately it is on the pressure side. When I looked at the leak with circulator running the stream out of the pinhole looked like a cobweb. My son will check with the Utica distributor tomorrow.
This discussion has been closed.