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  1. #1
    Join Date
    Dec 2005
    Location
    Spokane Wa
    Posts
    169

    york p.o.s. furnace

    I have a 7 year old 100 btu model fg8 80% furnace. The fan motor failed and when I pulled the blower I figured what the heck I will peak at the hx. I could not believe my eyes two out of the four cells were cracked. The next day I pulled the hx and found a 3/8 wide by 4" crack that I did not see untill I pulled it. I could not beleive that one of the worst looking hx ers I have ever seen was in my own house. It is a factory defect in that the crack is due to no air hitting the outside cell. The outside cell sits right above the slide channel for the blower so no air could hit it. It also cracked on the other side of that cell and cracked the cell next to it. I know it was firing fine since I have clocked the input and check the temp rise. I bet it is a waste of time for waranty other than the hx. I did not evan attemp checking into the hx since it would just crack again.

  2. #2
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,793
    Take the warranty credit towards a new furnace.
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    How many times must one fix something before it is fixed?

  3. #3
    Join Date
    Mar 2007
    Location
    Philadelphia, PA
    Posts
    58
    Just curious but would your average CO detector pickup on something like this?

  4. #4
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,793
    Co dectector would only catch it if CO were coming out of the furnace.
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    How many times must one fix something before it is fixed?

  5. #5
    Join Date
    Dec 2007
    Location
    MA
    Posts
    58
    Quote Originally Posted by mike08054 View Post
    Just curious but would your average CO detector pickup on something like this?
    a cracked heat exchanger does not mean you will have co. you will have flue gas entering the air stream, but flue gas does not always contain co. only in certain conditions a cracked heat exchanger allows for co to enter your home, only if present in the flue gas

  6. #6
    Join Date
    Apr 2007
    Location
    MN
    Posts
    297
    Quote Originally Posted by dsfitzgerald7 View Post
    a cracked heat exchanger does not mean you will have co. you will have flue gas entering the air stream, but flue gas does not always contain co. only in certain conditions a cracked heat exchanger allows for co to enter your home, only if present in the flue gas
    On an 80 or 90% furnace, a crack in the heat exchanger will cause the air to "short cycle" through the heat exchanger. Instead of the inducer motor pulling in air through the venturi of the burner for primary air to support combustion, it pulls it through the crack. This lack of primary air to support complete combustion will result in carbon monoxide being present as CO is a product of incomplete combustion. I have never had a stack CO reading of zero, even brand new furnaces usually burn around 10PPM in the stack.
    S**t or get off the pot!

  7. #7
    Join Date
    Dec 2007
    Location
    Ohio
    Posts
    2,876
    If there is a crack in the heat exchanger....CO doesn't matter. You shut it down and replace the unit or the heat exchanger....end of story.

    If you find a bomb in your basement do you buy a bomb detector or do you get rid of the bomb???

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