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  1. #1
    Join Date
    Apr 2010
    Location
    N. IL
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    8

    97% Modulating Multi-position

    First time installing two pipe pvc furnace. Install manual says no more than 30ft for the vent system. Literally impossible to pipe in less than 30ft. Problems if longer? Increase pipe size?

  2. #2
    Join Date
    Feb 2010
    Location
    In a boiler room
    Posts
    7,130
    Read the manual.

    Give us a model number off the furnace.

  3. #3
    Join Date
    Jan 2010
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    6,327
    Quote Originally Posted by ratitka View Post
    First time installing two pipe pvc furnace. Install manual says no more than 30ft for the vent system. Literally impossible to pipe in less than 30ft. Problems if longer? Increase pipe size?
    How many elbows you planning ?

  4. #4
    Join Date
    Apr 2010
    Location
    N. IL
    Posts
    8
    Luxaire Model # TM9M100C16MP12A

    Ive read the manual and like I said I can not make it outside under 30ft

  5. #5
    Join Date
    Jan 2007
    Location
    Mn the state where absolutey nothing is allowed
    Posts
    1,351
    not familiar with luxaire but im sure you could find another 100mtbu/ 4 ton drive furnace that you can vent farther than that
    my boss thinks its possible to repeal the laws of physics

  6. #6
    Join Date
    Jun 2009
    Location
    Nevada
    Posts
    139
    I believe York makes that furnace. If you check the manual I think you'll find that 30 equivalent feet is the maximum for 2" pipe, but 3" allows about 90' and 4" allows about 150'. Look for a section called "Combustion air/vent pipe sizing" and check the table.

  7. #7
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,194
    The I/O manuals aren't online. Seems very short. Is that for 2" or 3"?

    A-S/Trane Freedom 95 can go upwards of 200'

  8. #8
    Join Date
    Apr 2010
    Location
    N. IL
    Posts
    8
    wow I feel dumb, the 30ft is for the combustion air, but still the question exists, i cant reach outside with 30ft. can i go 40ft?

  9. #9
    Join Date
    Dec 2007
    Posts
    4,710
    as was said, reread the manual and make sure that is not the ONLY size and length to vent it in.

    most units I have come across have different distances for different size pipe.
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  10. #10
    Join Date
    Jul 2007
    Location
    Virginia
    Posts
    5,596
    Quote Originally Posted by ratitka View Post
    can i go 40ft?
    Yes, if you use 3" pipe.

    3" can go to 90 feet as DirkRoper said, minus any elbows (termination elbows are included in the 90 feet).

    Review the install manual for more details.
    Instead of learning the tricks of the trade, learn the trade.

  11. #11
    Join Date
    Jun 2009
    Location
    Nevada
    Posts
    139
    The pipe lengths are for each pipe. Using 2" you can have 30 equivalent feet of vent pipe and 30 equivalent feet of combustion air pipe. If you need to go 40 feet, use 3". Like rundawg said, read the manual.
    The manual is important for this equipment. Make sure you pay attention to the rules for running the condesate line or you'll probably be back, scratching your head, wondering why you have a pressure switch fault.

  12. #12
    Join Date
    Mar 2001
    Location
    Washington DC
    Posts
    73
    Okay, okay, it's been said but: read the manual. On many units there's a separate venting manual. There are LOTS of considerations, besides just length and number of elbows, height off ground, proximity to windows & doors and inside & outside corners, etc. You HAVE to study it closely to get it right the first time. Often the venting is some of the hardest work in designing a condensing boiler install. Do it right the first time.

    Sometimes novel solutions are called for: in one case I went straight through a chimney and out the other side, because otherwise it would have been too close to an inside corner of exterior walls. Worked fine.

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