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Thread: Combustion air

  1. #1

    Combustion air

    I just had a Rheem Elite system installed. I kept hearing water and waves in the morning and knew the PVC lines were holding water. I have about 12-18 inches of 2 inch pipe on each end but most of the run is 3" for about 12 horizontal feet. They were not pitched toward the furnace for drainage at all. I called them back and they lowered the inside exhaust line about 4 inches (dumping 2 gallons) but not the intake line. When I asked why not both lines the technician claimed no need? Is this true?
    Also I live in SE Pennsylvania and it is not unheard of to have 2-3 feet of snow, even more against my house on the deck. I am nervous if I leave for a couple days and snow builds up over the lines it will shut down freezing pipes and my pet. The technician claimed I can not raise the outdoor lines more or it will add too much resistance? The outside portion is not glued to allow me to adjust it but he just barely fit 2" pipe through the wall. Need I be concerned about this? See Photo attached. What is proper? Thanks
    http://www.flickr.com/photos/38738791@N07/5163340697/

  2. #2
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    normaly you can get by not pitching combustion air. the manuals say do it. you are allowed only so much pipe and so many elbows you might not have any allowance to rase the termination. then again it is 'sposed to be 12" above expected snow level

  3. #3
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    Quote Originally Posted by claudius2k View Post
    I have about 12-18 inches of 2 inch pipe on each end but most of the run is 3" for about 12 horizontal feet. http://www.flickr.com/photos/38738791@N07/5163340697/

    are the 2" X 3" reducers on each end of the 3" pipe in a horizonal or vertical pipe?

    reducing couplings should never be in horizonal pipe.

  4. #4
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    Quote Originally Posted by t527ed View Post
    are the 2" X 3" reducers on each end of the 3" pipe in a horizonal or vertical pipe?

    reducing couplings should never be in horizonal pipe.
    Unless they are offset reducing couplings.
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  5. #5
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    Quote Originally Posted by beenthere View Post
    Unless they are offset reducing couplings.
    i have never seen that type of fitting until another thread i was reading the other day had a sketch of one....

    will have to look for them next time i'm picking up fittings, they could come in handy.

  6. #6
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    Quote Originally Posted by t527ed View Post
    i have never seen that type of fitting until another thread i was reading the other day had a sketch of one....

    will have to look for them next time i'm picking up fittings, they could come in handy.
    When asking for them, just remember that fittings of those type are called eccentric couplings.
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  7. #7
    well one reducer is on the vertical 12 inches above the furnace, the other is horizontal a few inches before exiting the outside wall. However that is how the manufacturer's installation guide pictured them.

    Thanks

  8. #8
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    sounds like you should be ok with the reducers where they are. moisture is not usually a problem in the air intake.

    i would be concerned about how low your terminations are with the possible snowfall in our area raising them a couple feet would not cause that much resistance.

  9. #9
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    Here in my area I don't believe you are allowed to vent a condensing furnace out on to a deck. Something about the byproducts of gas, gassing you while you're on the barbecue or something else in the cooler months like I do?

  10. #10
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    Rheem/Ruud requires a trapped drain fitting in the horizontal combustion piping near the furnace. You don't want the condensation getting into the furnace. Any condensation in the exhaust line should run to the furnace and down the drain.
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  11. #11
    Thank you JdWendling. That is pretty much how I assumed it should work. Thanks for confirming.

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