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  1. #1
    Matthew Liang's Avatar
    Matthew Liang Guest

    Default Vent issues for high efficiency furnace

    This is a KeepRite high efficiency (90%) furnace (Sorry for the blurred image). From the two pictures we can see the pipes go down to the crawl space, come up and out of a wall. The intake pipe is less then 1 foot high. The exhaust pipe is about 2.5 feet high. So the problems are
    - the intake is too close to grade, it should be at least 1 foot high.
    - if venting to walkway, it should be at lease 7' high.
    - the intake and exhaust are too close, should be at least 3' apart.

    Thank you in advance for your comment.

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  2. #2
    Join Date
    Dec 2009
    Location
    Florida
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    Default Re: Vent issues for high efficiency furnace

    Quote Originally Posted by Matthew Liang View Post
    This is a KeepRite high efficiency (90%) furnace (Sorry for the blurred image). From the two pictures we can see the pipes go down to the crawl space, come up and out of a wall. The intake pipe is less then 1 foot high. The exhaust pipe is about 2.5 feet high. So the problems are
    - the intake is too close to grade, it should be at least 1 foot high.
    - if venting to walkway, it should be at lease 7' high.
    - the intake and exhaust are too close, should be at least 3' apart.

    Thank you in advance for your comment.
    Good workmanship there... Generally the intake and exhaust pipes should be above the snow line and no farther than 3' from each other. The reason for this is if too much of a atmospheric difference exists between the pipes, possibly from wind, the furnace will not start or it will shut down. Some installations have them horizontal with one facing out and the other facing down. They should drain into the furnace. The is to prevent the condensation from the furnace freezing in the pipe creating an ice backup that will shut down the furnace. Seen installation that even this didn't work and the pipe had to be insulated to stop the freezing. This installation needs to be moved up past the maximum snow line for the area, correct that beautiful exit work on the wall, and generally follow the manufacturers installation instructions. You didn't note, but how far are these from openings in the wall (windows, doors) both horizontal and vertical, and intake venting for other devices? There are restrictions there too.


  3. #3
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    Jan 2012
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    32

    Default Re: Vent issues for high efficiency furnace

    Dunno about this manufacturer, but my furnace (Carrier) specifies a maximum number of bends in the intake/exhaust piping. I'm guessing this one may be pushing the limit.


  4. #4
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    Florida
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    Default Re: Vent issues for high efficiency furnace

    Quote Originally Posted by thaddeus cox View Post
    Dunno about this manufacturer, but my furnace (Carrier) specifies a maximum number of bends in the intake/exhaust piping. I'm guessing this one may be pushing the limit.
    Good catch!


  5. #5
    Join Date
    Mar 2007
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    Lake Barrington, IL
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    1,363

    Default Re: Vent issues for high efficiency furnace

    What happened to the exhaust vent being pitched back towards the furnace to drain to the condensate? I'll take a wild guess that someone didn't read a manual.

    Eric Barker, ACI
    Lake Barrington, IL

  6. #6
    Join Date
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    Caledon, Ontario
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    5,005

    Default Re: Vent issues for high efficiency furnace

    1. Haven't seen any installations like the inside portion. Wow. Don't know of any manufactures instructions to allow this type of installation.

    2. The sheet metal and screws and flashing blend in well, very professional - not!

    3. The three foot rule distance from intake exhaust I am not sure that is an issue dependent on some manufactures exhaust/intake set ups.


  7. #7
    Join Date
    Jul 2010
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    Wisconsin
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    Default Re: Vent issues for high efficiency furnace

    Agreed, the number of elbows was the first thing I saw. Followed right behind with the huge trap that has been created, not sure which is exhaust or intake, but you have pipes going down and then one turns up, wonder how much water is sitting in there.

    Not sure about the walkway issue, if it is a private residence. Iím guessing with the hose reel and black pipe sticking out, this looks like a simple pathway along the home.

    That sheet metal work is first class... lol


  8. #8
    Join Date
    Jul 2010
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    Washington
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    70

    Default Re: Vent issues for high efficiency furnace

    Was there a condensate pump down in the crawlspace where the pipe hit it's low point?

    Is the 7' rule for venting at walkways in place to minimize potential vent damage or to protect against burning the skin of passers by? (My understanding is that the gas is low temp)


  9. #9
    Matthew Liang's Avatar
    Matthew Liang Guest

    Default Re: Vent issues for high efficiency furnace

    Quote Originally Posted by Luc V. L. View Post
    Was there a condensate pump down in the crawlspace where the pipe hit it's low point?

    Is the 7' rule for venting at walkways in place to minimize potential vent damage or to protect against burning the skin of passers by? (My understanding is that the gas is low temp)
    Thank you, everybody, for your comments. I came to that house again and had a look in the crawlspace. As you can see from the picture, there is a condensation line that dump the water into a hole on the crawlspace floor.

    The two pipe openings are on wall, a private walkway to the backyard. The intake pipe opening is about 1 foot above ground. And the exhaust opening is about 24'' above the intake.

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  10. #10
    Join Date
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    Default Re: Vent issues for high efficiency furnace

    Quote Originally Posted by Matthew Liang View Post
    Thank you, everybody, for your comments. I came to that house again and had a look in the crawlspace. As you can see from the picture, there is a condensation line that dump the water into a hole on the crawlspace floor.

    The two pipe openings are on wall, a private walkway to the backyard. The intake pipe opening is about 1 foot above ground. And the exhaust opening is about 24'' above the intake.

    1' above the ground? I assume you get snow where you are and it drifts.... need I say more?

    As for the "drain"... see the attached strip. (Wonder if the pipe filled up with water and they "fixed" it with the drain?) Double

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  11. #11
    Join Date
    Jul 2008
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    Snowbird (this means I'm retired and migrate between locations), FL/MI
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    Default Re: Vent issues for high efficiency furnace

    The entirety of the furnace venting system and its supply is suspect, color coding/staining for primer & chemical welding is completely different in CN.

    The installation is encroaching upon the burner guard/valve clearance and working space of the Cat I gas fired water heater. Unsupported, etc. Wrong materials at the time, must now be remediated to current standards for special systems for furnace, WH draft, connector and venting must be remediated to correctly accomodate orphaned status, sized, for heat values, draft, etc.

    The double draft hood is incorrect on same, as is the tape on the non-compliant SW venting material for the WH and clearances (air space, sheilding, etc.) about same. Orphaned WH venting system suspect oversized, spillage.

    Access to gas supply valves, sed. traps, and TPRV discharge. Storage present further compromises entirety.

    Appears multiple occurances of unqualified modifictions to systems and unqualified, unpermitted replacements.


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