Flue for a propane WH

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by kd, Apr 16, 2008.

  1. kd

    kd New Member

    Messages:
    207
    Have a propane WH mounted under the house in garage. For the flue, is there a rule as to how many feet horizontal you can go before you go vertical up to the roof? In the horizontal run, do you make it 1/4 inch per foot slope same a sewer line?
  2. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    Sorry I don't give advice on gas...
    [​IMG]
  3. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Messages:
    1,328
    Location:
    Columbus, OH
    Then why did you even post, Redwood?

    Ked, I would make it slope upwards as much as possible. If you don't get enough slope or you have a very long run you may get condensation in that flue which can lead to it rusting out. You can use B-Pipe to get around that as long as you are getting lift to get the gases out. If you're not a draft inducer may be needed, but I'm not sure if you can use these with a WH unless it's a power vented model.
  4. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    The picture above is the best advice I can give a DIYer on a gas installation!
    There are many serious ramifications that can occur from misinterpretations of advice. The advice I gave is the only safe advice to give!
  5. Spaceman Spiff

    Spaceman Spiff Architect

    Messages:
    277
    Location:
    Salt Lake City, Utah
    I would read the instructions for the heater. I have seen many different rise / run / elbow combinations in the same brand of heater, or of the same type. It all depends on the manufacturer, design, and how they tested it. Let the manufacturer tell you what is safe for their product.
  6. MACPLUMB 777

    MACPLUMB 777 TROJAN WORLDWIDE SALES RP

    Messages:
    679
    Location:
    Houston, Texas, United States
    I Would Go With Redwood On This ! !
    If You Have To Ask This Question It Shows You Should Be Using A Professional Plumber/hvac Not Trying To Guess Or Ask A Bunch Of
    Blind D. I. Y. Who Don't Know Any Thing About The
    National Fuel Gas Code Or The Proper Way To Vent Gas
  7. kd

    kd New Member

    Messages:
    207
    This was seen on a house inspection for a friend. I recommended that an earthquake strap be installed, T and P drain line be run to the soil and that a licensed plumber inspect the WH flue.
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