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  1. #1
    Join Date
    Mar 2009
    Posts
    6

    concentric venting

    What is the advantage of a using a concentric vent thru the roof instead of running 1 pipe for the vent thru the roof and ending the intake pipe in the attic? Can the non concentric venting cause problems when it is windy or degrade the high efficiency of the condensing furnace etc.?

  2. #2
    Join Date
    May 2008
    Location
    Missouri
    Posts
    3,535
    The difference in air pressures (if both intake and exhaust are not in same area) can cause nuisance lock-outs with the furnace. Also troubleshooting problems if intake is not readily accessible.

  3. #3
    Join Date
    Mar 2004
    Location
    SE Michigan
    Posts
    17,943
    The concentric kit is one pipe that will be running through the roof.
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    Theodore Roosevelt

  4. #4
    Join Date
    May 2008
    Location
    Missouri
    Posts
    3,535
    As I said in my earlier post, not venting both intake and pipe to the same area could cause intermitant lockouts due to different operating pressures under different weather conditions. A concentric vent runs both intake and exhaust thru a double wall pipe to the outside of the home, either thru the roof, or sidewall. Leaving the intake inside the roof (in attic), as John ask, can lead to problems.

  5. #5
    Join Date
    Mar 2009
    Posts
    6
    The reason I asked the question is because I just had a 95% Lennox installed last week. I spoke with a neighbor and discovered that his new hvac installed last fall by the same dealer was also a Lennox. The neighbor has a concentric vent installation and the pipe and flashing are black to match the roof. Mine is a white piece of PVC with aluminum flashing. These are condominiums and only 3 doors apart.

    My installation doesn't look nearly as good, and are you telling me that if won't be as efficient and or as reliable?

    Thanks for your input,

  6. #6
    Join Date
    Jun 2007
    Location
    Darby, PA
    Posts
    558
    You can paint a concentric black if needed. But it is wise to have both terminations in same area, as stated before, due to consistent pressures. A concentric is a two pipe termination, also as previously stated. This could have been worked out with installing contractor if cosmetics were a problem. A concentric is a better, more appealing termination than using a two pipe setup (meaning you would see one pipe for intake and one pipe for exhaust on the roof as opposed to a "one pipe" look provided by the concentric.) As long as PVC is sized properly and installer follwed mfr. specs, you should not have any issues.
    Psalm 51:10, 12

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,074
    It won't effect efficiency, since its still pulling outside air.
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  8. #8
    Join Date
    Dec 2007
    Posts
    4,710
    are you sure you do not just have a white concentric vent pipe?
    color does not determine what it is.
    did you look in the attic to confirm?

    do you both have the same furnace?

    if installed by the same contractor and the same furnace, one would think they did them the same.

  9. #9
    Join Date
    Jan 2005
    Location
    USA
    Posts
    1,453
    Like previously stated it may be a concentric. Does it look like this?

    The pic here will be upside down for your roof application.
    "It's always controls"

  10. #10
    Join Date
    Mar 2009
    Posts
    6
    Yes, I'm sure that it is not a concentric vent pipe, it is a piece of PVC cut to match the roof angle and the other PVC pipe ends in the attic. What upsets me is that the neighbors HVAC was installed 4 months ago by the same company and his Condo is exactly like mine so there is no reason for one to be installed differently than the other.

  11. #11
    Join Date
    Dec 2007
    Posts
    4,710
    posting pictures may be helpful in giving a definitive answer.
    may want to call the install company and have them come out to verify proper install and ask them to explain the reasoning yours was done different.
    also, as stated prior, this may cause issues down the line and better to fix it now.

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