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  1. #1
    Join Date
    Nov 2007
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    Question about water output with Condensing Furnace

    I'm thinking of replacing a wall furnace in my workshop thats over a detached garage with a small condensing furnace. I don't have a proper drain in it but I do have a 2" line roughed in that I could dig some sort of small dry well for. Lots of work, and I'm afraid it might freeze solid in really cold weather. I'm in Chicago. I really don't want to dump a drain out the side wall of the garage either as a contractor suggested, it's a very handsome coach house. So here's the question, how much water will a 45K BTU furnace, mostly set at 50 degrees make? Can I possible drain it to a 5 gal bucket and empty it once a week or so? And guy's no please snide comments about being a hack, it's a garage workshop for pete's sake!

  2. #2
    Join Date
    Nov 2001
    east kansas
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    First, don't set your furnace to 50F. Lennox recommends the minimum temperature at 65. Even for a condensing furnace. Many don't have a stainless steel primary heat exchanger. The furnace will be in a continue state of "cold soak". Meaning the primary heat exchanger will corrode prematurely.

    I don't know how much water is produced at any giving conditions. The furnace will run longer when it's cold outside compared to mild weather. But you can drain it into a bucket if you want. I would install a condensate pump, and pump it to an inconspicuous location.

    Be careful if you drain it into a bucket. The condensate is slightly caustic. A customer with a condensate problem decided to siphon it out of this furnace instead of paying OT for me to come out and fix it over the weekend. The condensate burnt the inside of his mouth. He pays OT now when he has a problem.

  3. #3
    Join Date
    Mar 2005
    leland nc
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    more then likely when it get cold you will be dumping that bucket once a day

    if you cant provide a proper drain and be sure it wont freze the dont put a 90plus in

    get an 80 percent furnace and you wont need to worry about water and freezing and you shouldnt go lower then 55 IMO

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