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  1. #1
    Join Date
    Oct 2010
    Location
    Chicago
    Posts
    36

    Confused High CO levels in flue pipe - Janitrol

    Hey guys. I did a combustion analysis on a 80k BTU Janitrol Gas Furnace. Prior to the test I ran a new chimney liner (6 inch diameter 20 foot long), added a 6-5-3 Y where I connected the furnace and the Hot Water Tank. Combustion test results were 2 ppm for the HWT and 130 ppm for the furnace. Draft is 0.02 iwc for both. The furnace is under firing with Oxygen levels around 15%. Increasing the gas flow will get my Oxygen level to a decent 9% but the CO level increases to over 3-400 ppm. I haven't came across this situation before, so here I am, asking for advice.

    Respectfully, Chris
    Last edited by Stamas; 11-17-2010 at 06:45 PM. Reason: name

  2. #2
    Join Date
    Oct 2010
    Location
    SW Michigan, near Battle Creek
    Posts
    921
    If it is a GMP GMN or GMPN it has a bad heat exchanger. the sides of the clamshell are peened together and pop apart. you will find little rings of metal when you pull the blower, if it is a GMP. they are on top of the secondary on the 90%.

    If it is any other model it is still probably a heat exchanger.

    If the readings change when the blower kicks in that confirms it.

    exhaust CO is my favorite heat exchanger diagnostic.
    (after mark 1 eyeball

  3. #3
    Join Date
    Jul 2010
    Location
    nebraska
    Posts
    1,629
    Can't get specific on this forum chris but rust and dirt is the enemy.

  4. #4
    Join Date
    Oct 2010
    Location
    Chicago
    Posts
    36
    Thank you guys for the quick response. Didn't have too much time for proper testing, but I will head back tomorrow morning. My rough diagnostic was the heat exchanger, but didnt saw a big difference in o/co levels. On my way home I stopped by the supply store and got me a new tester (eagle 2x) with a heat exchanger test function. I hope it's the heat exchanger because CEDA will pay for a new furnace if I can prove it. Will come back tomorrow with the new test results.

  5. #5
    Join Date
    Oct 2010
    Location
    Chicago
    Posts
    36
    Quote Originally Posted by martyinlincoln View Post
    Can't get specific on this forum chris but rust and dirt is the enemy.
    Will scan my EPA/NATE cards tmrw and get on the pro forum.

  6. #6
    Join Date
    Jul 2006
    Posts
    6,627
    Stick a fork in it, its done
    You sure are cocky for a starving pilgrim.

  7. #7
    Join Date
    Sep 2010
    Location
    Western, MO
    Posts
    871
    Quote Originally Posted by XMéfiant View Post
    Will scan my EPA/NATE cards tmrw and get on the pro forum.
    Don't forget about your post count.

    jim
    Common sense isn't very common anymore.

  8. #8
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,777
    Sending in your app before reaching 15 post. Will just end up slowing down the process.

    Follow all application instructions.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  9. #9
    Join Date
    Oct 2010
    Location
    Chicago
    Posts
    36
    ok guys. i went back yesterday and ran a few more tests. did a heat exch test. oxygen and excess air increased slightly with blower on, so i assume it's a hairline crack.
    thanks all for your help

    chris

  10. #10
    Join Date
    Oct 2010
    Location
    Chicago
    Posts
    36
    Just heard back from CEDA. Furnace replacement accepted. Thank you guys!

  11. #11
    Join Date
    Sep 2002
    Location
    Northeast Ohio
    Posts
    4,855
    ANY post counts toward your total needed (15), five minutes on here and you can fix that. Welcome to the BEST HVAC site on the web
    A good HVAC tech knows how, an educated HVAC tech knows why!

    DEM


  12. #12
    Join Date
    Jul 2010
    Location
    Bay Area
    Posts
    261

    Talking

    Welcome Chris, this place really is the best, don't hold off on applying for pro. I just got accepted yesterday (took about a week to process) and wish I woulda done it months there's so much info on the pro side you feel like you find a gold mine

  13. #13
    Join Date
    Oct 2010
    Location
    Chicago
    Posts
    36
    Thanks for the warm welcome! Will definitely do it once i reach my post count, hopefully today.

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