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  1. #1

    Confused Fresh Air Intake for High Efficiency Furnaces

    I am a homeowner in New Jersey who recently had a Carrier Infinity ICS Modulating Gas Furnace (model # 58mvc) installed. In these types of furnaces the exhaust is vented outside via a PVC pipe. What about the Fresh Air Intake? My contractor has not vented it outside but left it inside. The furnace is located in my work shop area. Is this allowable or isn't it against best practices (or even code)? Case in point, by leaving it in the shop and there is a gas leak, or saw dust and other impurities get sucked in, could there be problems?

  2. #2
    Join Date
    Dec 2010
    Location
    The Quad-Cities area (midwest).
    Posts
    2,744
    Quote Originally Posted by rdes View Post
    I am a homeowner in New Jersey who recently had a Carrier Infinity ICS Modulating Gas Furnace (model # 58mvc) installed. In these types of furnaces the exhaust is vented outside via a PVC pipe. What about the Fresh Air Intake? My contractor has not vented it outside but left it inside. The furnace is located in my work shop area. Is this allowable or isn't it against best practices (or even code)? Case in point, by leaving it in the shop and there is a gas leak, or saw dust and other impurities get sucked in, could there be problems?
    He cut corners on you.

  3. #3
    Join Date
    Jan 2007
    Location
    NE OHIO
    Posts
    778
    usually not too hard to run intake outdoors where it should be to keep from pulling chemicals or whatever in. Not sure if that has to be two piped. Some do.

  4. #4
    Join Date
    Jul 2010
    Location
    georgia
    Posts
    562
    ditto.

    according to my Rheem 90% install manual, any place there could be impurities or chemicals (such as a laundry room and bleach) the unit's intake should be piped outdoors.

    call your furnace's mfg and explain the installation location (garage and any contaminants) and ask if its acceptable not to be piped outside. If they say its OK, get a follow up confirmation via email or fax and file it away with your warranty info.

    you may also want to ask your local code department.

    If either of these come back saying it needs to be piped outside then the contractor needs to fix this for you for free.

  5. #5
    Join Date
    Jun 2010
    Location
    Danbury Ct 1/2 hour from NYC
    Posts
    204
    You can pull air from where the furnace is based upon the size of the room and the size of the furnace. I always run the intake out with the exhaust just to be on the safe side. If it is a direct vent then he should run the other pipe to draw from the exterior. I have done it in a case where they wanted temp heat on a jobsite but before a c.o inspection or someone occupies the dwelling I would make it right. I have ran the intake to a crawl space vent or a place it can pull outside air but I never leave it a 1 pipe. Ct building codes are very strict and I love it because you actually have to be licensed and know what you are doing here unlike some other states I have been!!

  6. #6
    Join Date
    Mar 2010
    Location
    North Ridgeville, Ohio
    Posts
    163
    Best practice is to run the intake. Code will depend on your local inspectors.
    Do, or do not. There is no try.

  7. #7
    Join Date
    Feb 2010
    Location
    Ontario Canada
    Posts
    1,341
    The installing contractor should have left the Maintenance/installation manual for this furnace on site... I do not know where you live but in Ontario Canada it is a requirement under TSSA.
    It should tell you in this manual if it is necessary for the air intake to be outside. I know I would want it outside if it was my house.

    There must be inspectors for this in your area, call one in and have it inspected.

  8. #8
    Join Date
    Jan 2008
    Posts
    2,089
    With only 1 pipe, you're increasing infiltration. All the air blowing out the exhaust is being replaced with outside air, in effect, lowering the efficiency.
    "Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler

  9. #9
    Join Date
    Jun 2009
    Location
    Toronto
    Posts
    7
    You should always try to bring outside air, especially if you have a hobby room and are using chemical n' stuff

  10. #10
    Join Date
    Aug 2009
    Location
    Michigan
    Posts
    88
    The intake pipe must be vented outside, or in a vented crawl space, or in the attic per installation instructions.

  11. #11
    Join Date
    Jan 2011
    Location
    Massachusetts
    Posts
    83
    I have run 1 pipe many times sometimes at cust request dont think it is smart to do in your case in massachusetts code determines location as confined or unconfined based on square footage of furnace room but in a shop asking for trouble

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