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  1. #1

    CO coming from furnace

    I was waken up by my CO detector this morning. I went and got a CO monitor I have from work and it read 35ppm, not too high but 0ppm would be ideal for my house. I turned off the furnace and threw some fans in the windows and it went down to 0 ppm. I turned the furnace on again this morning and placed the monitor right by the vent and it indicated CO but only 4-5 ppm. The furnace is Trane XR80 and is only 7 years old. I thought maybe it could be ventilation problem, but I'm a new home owner and I am just not sure if it is something I could fix quickly or if I should just call a tech.

  2. #2
    Join Date
    Sep 2012
    Location
    Hebderson Ky
    Posts
    55
    Call a tech.

  3. #3
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,721
    Dodged a bullet!

    Run right out and buy a handful of lottery tickets.
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

  4. #4
    Join Date
    Feb 2010
    Location
    In a boiler room
    Posts
    7,068
    Go here to find a company certified in CO diagnosis. www.stopcarbonmonoxide.com

    Is there any chance you have a natural draft water heater common vented into the same flue?

  5. #5
    Yea the water heater and furnace do have a common natural drafted vent on the same flue

  6. #6
    Join Date
    Feb 2010
    Location
    In a boiler room
    Posts
    7,068
    Quote Originally Posted by luke8615 View Post
    Yea the water heater and furnace do have a common natural drafted vent on the same flue
    Then the furnace exhaust is likely spilling out the water heater draft hood instead of going up the chimney. This could be due to a plugged chimney, or insufficient combustion air.

    It's a very dangerous combination for a water heater and an induced draft furnace to be common vented, yet is somehow ok per code!!!!

    This is really the only way to make that combination safe. See attached pic. That open draft hood on the water heater is dangerous.
    Attached Images Attached Images  

  7. #7
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    6,744
    Do not run the furnace until you get this problem resolved. This is a dangerous situation

  8. #8
    Join Date
    Jun 2011
    Location
    Seattle WA
    Posts
    1,238
    35 ppm throughout the house is high if you ask me. 10ppm exposure over 8 hours can cause problems
    America; first we fight for our freedom,
    then we make laws to take it away.

    -Alfred E Newman

  9. #9
    Join Date
    Jul 2009
    Location
    Columbia, MD
    Posts
    3,836
    I like 0PPM in the homes i work in.

    Follow chucks picture. That is the only way to make sure your appliances are venting safely.

    turn off both the water heater and furnace.

    water heaters kill more people then furnaces do.

  10. #10
    Join Date
    Aug 2004
    Location
    S.E. Pa
    Posts
    6,166
    A UL listed CO alarm showing 35ppm may actually mean 100+ as these alarms are notoriously inaccurate. BTW, you can now claim you have had CO poisoning since the alarms are set to alert only once you've reached a blood level of 10% carboxyhemoglobin. Get a pro who's certified in CO, and yes, you need the setup Chuck illustrated because a common vented 80% furnace can happily vent out the water heater draft hood without tripping any of the three safeties on the furnace. Meanwhile, the water heater has no safeties for venting. Also have a pro inspect your venting system. Even a slight resistance may result in flue gas spillage depending upon sizing, layout, and installation.

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