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Thread: Cracked heat exchanger question

  1. #21
    Join Date
    Nov 2006
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    Southeastern Pa
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    Basically, I have bern told that the American Fuel Gas people say that no defects are acceptable for safe operation.

    As for the physics of how the CO can get out in the situation you described, it is simple. Gaseous vapors dont't always behave as expected. Due to turbulence, pressure can force air into the hx and at the same time, force flue gasses out into that airstream.

    It would be nice and comforting to think that blower pressure would ensure that all of the flue gasses are pulled along by the inducer, but that idea is not 100% reliable in practice.
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  2. #22
    Join Date
    Feb 2011
    Location
    Peoria, IL
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    Quote Originally Posted by timebuilder View Post
    Sadly, all the maintenance in the world will not prevent a defective heat exchanger. Heat exchangers are made of various types and qualities of metal. Some will last for a very very long time. I have Lennox units that are 13 years old that have never had a heat exchanger problem, and never had a heat exchanger replaced. I have Carrier units that are half that old where there is a hole I can stick my pen into.

    It's the metal, and the associated costs in producing the part that are the controlling factors in hx life. Mfgs can make a heat exchanger that would last 30 years. They instead predict how long the unit will last overall, and use that as a benchmark for hx quality.

    This is the sad truth, it comes down to cost of material, how often they can sell you another one. its business, Things years ago lasted a long, long time. But if it does, you cant sell another one to the same person for a long long time. (stealing from the bionic man series) We have the technology to build it better.

  3. #23
    Join Date
    Jan 2006
    Location
    Powell River, BC, Canada
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    763
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    Realist: is that an oil frurnace HX? If so, what brand/model? Just curious, as I have many oil furnaces in my area and I don't recognize the HX from the pic. Thanks!
    Where are you? Are you done yet? I got ONE more call for you.....

  4. #24
    Join Date
    Mar 2011
    Location
    Portsmouth, VA
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    I always condemn the unit when I see this condition.

  5. #25
    Join Date
    Mar 2013
    Location
    Billington Heights, NY
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    21,625
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    looks like it may be a horizontal drum?

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