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  1. #1
    Join Date
    Apr 2008
    Location
    Upstate New York
    Posts
    721

    How much Co is in the vent fumes ??

    I notice neighbors and ours too furnace vents that go out the back of the house. The "plume" of the vent seem to SOMEDAYS hang around the side of the house or creep up under the overhead soffitt even though the vent is 8 ft below it.

    My ? is you can smell it if you walk by it but is this loaded with Co ??

    If so I would think everyone should go UP thru the roof with the vents ???

  2. #2
    Join Date
    Aug 2004
    Location
    S.E. Pa
    Posts
    6,050

    Cool

    Call an HVAC pro with a combustion analyzer to test in your house including the attic. He can also measure the vent terminations to ensure they meet the code requirements.
    CO has no odor but you may be smelling aldehydes, which are present only from incomplete combustion and accompany CO. He can probe both furnace terminations to see who's is exhausting what. If it is your neighbor's crossing over, you can inform him.
    What you are seeing is a steam plume. It doesn't mean the gases have to be in it but they can. You may want to ask the tech about the possibility of extending the vent up above the roof. It all falls back to the appliance's listed instructions.
    HTH

  3. #3
    Join Date
    Jul 2006
    Location
    NW burbs of Detroit
    Posts
    6,058
    Sounds like you go a 90% furnace.

    Judging from the description you gave, I don't feel you are getting any recirculation of co. That's mostly water vapor comming out the plastic pipes.

    As long as the areas you describe don't discolor than you should be fine.

  4. #4
    Join Date
    Apr 2008
    Location
    Upstate New York
    Posts
    721
    Its not really a bad smell or a real stron smell just a slight plastic type smell.You have to be real close to it to smell it. Wonder if its because the pipe is brand new ??

    On mine you too have to be very close to it and it too has a sorta plastic like sweet smell..

    I dont remember them taking a reading from my vent when they did the start up is this something they should have done ????

    Mine is a brand new Rheem 2 stage 95%

    Also I wondered I see alot of vents near windows, what if the furnace was running and for some reason you had a window cracked and the wind was blowing toward the house, wouldn't the house fill with Co or is there not enough in it to matter ??

    His installer told him his new 92% furnace had so little Co that even if it broke the vent and was going inside it wouldn't even set off a Co detcetor ??

    I know that they do sell vent free fireplaces and kitchen ranges have no vents but are these new furnaces really that clean burning that they omit little or no Co ??

  5. #5
    Join Date
    Apr 2008
    Location
    Upstate New York
    Posts
    721
    Also now taht im thinking about it, the condensate drain they have running into my drain for my AC which is 1" dia PVC that goes to my basement floor drain. If this condensate is so corrosive as I have heard wont it eat the cast iron drain pipe ??

    Dont mean to be paranoid but I am

  6. #6
    Join Date
    Sep 2003
    Posts
    1,615
    Anything is a guess

    After 30 years of eyeballing flames because I know what they look like and there couldn't possibly be CO in those blue flames.

    I am now doing combustion testing.

    So If you aren't testing, you are just guessing

    So the answer is maybe and you won't know until it is tested for sure

  7. #7
    Join Date
    Feb 2007
    Posts
    999
    Per HVACLOVER:

    "Sounds like you go a 90% furnace.

    Judging from the description you gave, I don't feel you are getting any recirculation of co. That's mostly water vapor comming out the plastic pipes."

    Just for my own information: If in fact it is water vapor, wouldn't that mean that some efficiency has been lost (vapor not condensing; heat exhausted)?

    AM

  8. #8
    Join Date
    Jul 2006
    Location
    NW burbs of Detroit
    Posts
    6,058
    Quote Originally Posted by ampulman View Post
    Per HVACLOVER:

    "Sounds like you go a 90% furnace.

    Judging from the description you gave, I don't feel you are getting any recirculation of co. That's mostly water vapor comming out the plastic pipes."

    Just for my own information: If in fact it is water vapor, wouldn't that mean that some efficiency has been lost (vapor not condensing; heat exhausted)?

    AM
    Not at all. The water vapor is all that's left of the gas because it burns it so thoroughly.

  9. #9
    Join Date
    Apr 2008
    Location
    Upstate New York
    Posts
    721
    so there is NO Co in the exhaust ?/ So if you open a door down wind of the plume and some blows in the house its not Co ??

    Most instructions say " vent no closer than 3ft to an inside corner" suposedlly so it doesnt ruin paint ??

    I realy wonder how much Co is in the plume

  10. #10
    Join Date
    Apr 2008
    Location
    Upstate New York
    Posts
    721
    how could I test the exhaust to see the amt of Co ?? I have had companys tell me there is hardly any ???

  11. #11
    Join Date
    Apr 2008
    Location
    Upstate New York
    Posts
    721
    is there anwhere you can look this up

  12. #12
    Join Date
    Jul 2006
    Location
    NW burbs of Detroit
    Posts
    6,058
    Quote Originally Posted by cvcman View Post
    so there is NO Co in the exhaust ?/ So if you open a door down wind of the plume and some blows in the house its not Co ??

    Most instructions say " vent no closer than 3ft to an inside corner" suposedlly so it doesnt ruin paint ??

    I realy wonder how much Co is in the plume
    i did not say that. But was trying to as non-technical as possible.

    And to answer your question about proximity to windows; it is four feet for a one pipe sysytem (indirect vent) and one foot for a two pipe system (direct vent).

  13. #13
    Join Date
    Aug 2008
    Location
    San Clemente, CA
    Posts
    1,069
    If you look at your install instructions for this furnace you speak of (installers should have left it with you the homeowner). The manufacturer allows side wall vent termination's with clearances listed to items such as windows, doors and overhangs.

    If it is burning properly your CO level would be around 2 to 8% PPM (parts per million). There is other stuff in what we call “products of combustion”. Mostly it’s water. Did you know if you burn a 100K BTU furnace for 1 hr it will make 1 gal of water (H2O). The high efficiency units have a condensate drain to drain off some of this water. Some of it escapes out the flue pipe, that is why it has to slope back to the furnace so water inside the pipe can drain back.

    80% AFUE furnaces also make 1 gal of water per 100K BTU’s in one hr. They are designed to vent 100% of this water out the flue pipe in the form of water vapor. So the 80% models keep the flue gases above due point until they exit to the outside. Sometimes when it’s cold you can see water vapor coming from these vent pipes too.

    Hope this answers your questions.

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