Cold drafts in basement

Discussion in 'Water Heater Forum, Tanks' started by oldradio99, Feb 26, 2014.

  1. oldradio99

    oldradio99 New Member

    Messages:
    11
    Location:
    Illinois
    Over this past weekend my 12 year old water heater leaked. No plumber would come out without a village permit. And it being Presidents' Day, that would mean 3-4 days without hot water. So off I went to Home Depot and bought this:

    http://t.homedepot.com/p/GE-50-gal-...nergy-Star-Water-Heater-SG50T12TVT/202771179/

    Installation was fairly easy but now I have an issue. This unit has a power vent control on the top which means it only releases exhaust when the burners fire. The rest of the time, the butterfly is closed.

    The venting actually runs all the way up my chimney. My furnace used to use the same venting until we replaced that with a high efficiency.

    Now my problem. When the water heater is not firing, I get a cold draft coming back down the vent. The basement is now actually 2 degrees colder. Of course it is zero outside.

    So what can I do if anything?

    Thanks.
  2. Dana

    Dana In the trades

    Messages:
    2,915
    Location:
    01609
    You are suffering what's referred to as the "orphaned hot water heater" problem. What it boils down to is that the flue diameter of the chimney is many times too big for the BTU output of the hot water heater's burner, and it won't draft properly during cold weather. Even though the power vent keeps it from backdrafting while firing, you'll still get flue condensation of the exhaust, which will eventually destroy a masonry chimney making it structurally unsound from the inside out due to the mild acidity of that condensate. If the flue venting is a stainless steel liner that was sized for the combined output of a hot water heater & furnace you're probably protected from the corrosion issues, but not from the 20+ hours/day of backdrafting. (I'm guessing this is an exterior chimney off the side of the house, and not a chimney that runs through conditioned space from the basement to the attic?)

    The easiest/cheapest solution is usually to side-vent the water heater using the correctly rated & sized PVC vent pipe, and seal up the abandoned flue at the bottom with brick & mortar (or sheet steel & mortar). With side venting you don't have the convective forces of 20-40' of vertical flue to back draft through the leaky butterfly vane.
  3. oldradio99

    oldradio99 New Member

    Messages:
    11
    Location:
    Illinois

    Could I, or really should I, connect to the same PVC I use for my furnace vent with a Y connection?

    The old hot water heater was a closer connection of the flue to the heater while this one has a 1 inch gap.
  4. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,249
    Location:
    Land of Cheese
    You can only follow the venting instructions that came with the heater. If you tie the two together, under certain conditions one could blow exhaust into the other. I would believe that a separate vent is the only right way to do it.
  5. Dana

    Dana In the trades

    Messages:
    2,915
    Location:
    01609
    You can't legally or safey Y-into another vent with one OR the other OR both being power drafted.
  6. oldradio99

    oldradio99 New Member

    Messages:
    11
    Location:
    Illinois

    I will have my furnace guy look when he does my spring cleaning.

    Maybe he can run another exhaust line.

    Thanks.
  7. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,358
    Location:
    Yakima WA
    You have been given good advice. You need a separate PVC vent pipe for your water heater. I have exactly the same thing in my home. Got rid of the old chimney years ago. My first power vent actually used 4" PVC, but my new one uses just 2". There are restrictions on distance and elbows, but this is usually not too much of a problem. A plumber or your furnace man can make short work of this. I would do it now rather than later if the weather isn't too severe.
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