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  1. #1
    Join Date
    Jul 2012
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    A/C condensation line shared with HE furnace?


    We recently experienced a large amount of water pouring out from the top of our furnace. I am not much of a handy person, so after poking/prodding and saying "Yup, it's wet" I called someone in...

    I did a little research and I think I understand that this is the evaporator for the A/C and there is a pan that drains out, where clogging is a common problem.

    There was, at the time of the issue, a black tube that goes in to the basement floor, but I couldn't actually see where it went due to to some framing lumber for a very shoddy wall the previous owner used to enclose the utility room. I pulled the tube out, and stuck it in a bucket to see if any condensate was coming out. We turned the A/C on, and a very small amount came out but the unit still leaked all over.

    This was the point where the repairperson came. He said that the plastic-metal hybrid elbow coming out of the side of the furnace was no good, and prone to buildup, and suggested a plastic elbow and some new clear plastic tube.

    The furnace itself is a 92% efficiency Ducane brand gas furnace (I think it's called a 'Fit-All' or something like that). Anyway, again my research led me to understand that this is a condensing furnace and it too has a condensation drain line. This was rigid plastic (ABS? white?) and went straight from a T down to an elbow across the floor to the same obscure location the evaporator line went to.

    Whatever schematics I could find - not even sure they were the right ones - made me believe that there's an internal trap in the furnace, so one outside is not necessary (whatever that means!)

    In the installation of the new drain line, he connected the drain line to the top of the 'T' on the side of the furnace. I *thought* I read that this was not a good idea, but I don't know enough about the terminology and all the different factors, and he said it was absolutely fine. Searching the internet/forums leads me to lots of information, but it's either in jargon or not specific enough that I can relate it to my situation, and $$$ later I'm just wanting to make sure that this was done right. His English was not very developed, so he wasn't really able to assure me of anything except "It's OK, it's OK", but he was prompt and I would call him again provided this wasn't improper.

    Here are some pictures if they help:



    Third - for the heck of it

    Thanks in advance for any information..
    Last edited by jpsmith1cm; 07-05-2012 at 05:54 AM. Reason: Pricing

  2. #2
    Join Date
    Dec 2002
    SouthEast NC ICW & Piedmont Foothills
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    from what I could tell from photo

    1- the condensate drain pipe should not decrease from origination size

    2- that black pipe is what mfg wants
    It`s better to be silent and thought the fool; than speak and remove all doubt.

  3. #3
    Join Date
    Jul 2012
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    Thread Starter
    Thanks for the reply!

    The decrease in size, now that you've said it, appears so obvious I am kicking myself for not asking up-front.. how serious of a faux pas is this? Should I remedy it immediately? Observing the clear pipe, I see a rather steady flow of condensate, but it is not at a volume that I would eyeball as being greater than what the smaller diameter pipe could handle.

    I presume that the danger here is that in the event the rate of flow is too much, it will first back up in to the furnace? Or does (could?) the internal trap prevent that?

    As for the black pipe the manufacturer wants, do you have any insight in to what the difference is, specifically short term (e.g. one season)?

    Thanks again.

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