Power Vent Water Heater Exhaust Question

Discussion in 'Water Heater Forum, Tanks' started by mtcummins, Sep 7, 2013.

  1. mtcummins

    mtcummins In the Trades

    Messages:
    380
    Location:
    Pittsburgh PA
    Hi all,

    I have a power vent tank in an investment property, with a 3" PVC vent that turns horizontal immediately off the top of the blower and goes to the side wall, not sure exact distance, but around 15 feet or so. It has a pretty significant amount of pitch up towards the wall.

    Problem is, its a head banger and its a relatively high traffic area for a basement, as there is a garage entry there.

    I was wondering if its legal/safe to put a slight downward pitch on the exhaust line since its getting blown out of any exhaust anyway? I think just like a 1/4" per foot or so would be enough to make it out of headache range for most people. Since its just going a short distance out a side wall, the downpitch would allow any condensation to drip outside, not get trapped anywhere, and the blower should keep it free from gasses.

    I know its not how they're spec'd to be installed, but was wondering if this is a situation where it would be ok, or if I'm just stuck with it being a constant headache.

    Thanks!
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,889
    Location:
    New England
    IT comes down to what's in the manufacturer's installation manual. if you don't have yours, you may find it online at the manufacturer's website. Code essentially says installed per the manufacturer's instructions. I've seen some that want it to slope out, and some that require it to not slope out (i.e, back to the tank). If you have enough room for the about 4" of drop on the pipe over that distance, nothing says you can't go up a bit more directly out of the top of the tank.
  3. mtcummins

    mtcummins In the Trades

    Messages:
    380
    Location:
    Pittsburgh PA
    Ok, will have to look and see if they left it for me or not, or find it online. I haven't really looked into this much yet, just been one of those nagging back burner problems that needs to be addressed soon.

    Thanks Jim. I wasn't aware that they ever spec'd them to slope out, that would be helpful. Will have to check and see what it says, not even sure what the make is off hand.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,889
    Location:
    New England
    It all depends on how they manage flue condensation, or if it's a problem or not. Using PVC, they must expect some condensation, since PVC can't handle much heat, and there will be some. If the WH has a condensate collection system and a drain, it would likely slope back, if it doesn't, it expects to drain it outside, and it must therefore slope in the correct direction. I've had one of each.
  5. mtcummins

    mtcummins In the Trades

    Messages:
    380
    Location:
    Pittsburgh PA
    Ok, didn't realize they made them both ways. My own home has a commercial condensing WH with power vent, it collects all the condensation, has drains, etc. It's used for both DHW and radiant floors.

    I don't recall seeing a drain on this model, so maybe it is supposed to be sloped outward in the first place. Wouldn't surprise me too much, a lot of the things I've seen in this house were "almost" installed correctly. Seems like they were the scary type of handymen... knew just enough to be dangerous, and confident enough to attempt the work anyway... <sigh> Oh well, I'm getting it all fixed up right pretty quickly now, I don't have any interest in having things done that way.

    Thanks again Jim. I won't be at the property again until tomorrow, but will check it out then.
  6. mtcummins

    mtcummins In the Trades

    Messages:
    380
    Location:
    Pittsburgh PA
    Found the manual near the heater, but it had nothing about pitch of vent pipe (go figure). Looked up what I believe to be the same manual online, and it says it can slope 1/4"/foot up or down. Doesn't seem to have any water collection/drainage system, so I would think that down is better anyway...

    My heater is a Ruud PVP50E-1 A. I could only find a manual for the PVP50E-2, but it looks like its basically the same heater. Manual they link for that model seems to be a generic manual for all their Power Vent models.

    So, guess I'll just raise it up as high as possible to keep that 1/4"/foot slope going downwards. I think that will get me just enough to get rid of the headache.

    Thanks for the help!
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