Any advantage to TOP mounted T&P Valve?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by tl2tl, Nov 6, 2008.

  1. tl2tl

    tl2tl New Member

    Nov 6, 2008
    Some gas water heaters have an OPTIONAL top T&P valve location.

    Is there any advantage in getting one of these?

    T&P Valve looking at two sides.
    Last edited by a moderator: Apr 24, 2009
  2. Gary Swart

    Gary Swart In the Trades

    Sep 1, 2004
    Yakima WA
    The purpose of the T/P valve is to monitor temperature and pressure and open if the limits are exceeded. I see no difference in where the valve is located, top or bottom, to do this.
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  4. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    Historically, T&P valves were recommended to be installed vertically so that there was no way for gravity to affect the operation because of drag on one side of the shaft. The other is that the hottest water is at the top of the tank, whereas side mount openings could be up to 6" lower, but MUST NOT be more than 6" down.
  5. tl2tl

    tl2tl New Member

    Nov 6, 2008
    Thanks for your replies.
  6. Nate R

    Nate R New Member

    Jan 11, 2007
    I perform R&D testiing at small engine manuf.
    Milwaukee, WI
    Could a side T&P valve get in the way in some very tight alcove installations?
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