T&P drain

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by bsperr, Dec 15, 2008.

  1. bsperr

    bsperr Member

    Apr 23, 2008
    Athens, GA
    I need to replace the T&P valve on my water heater and am wondering about how to connect the drain. The valve is currently hard piped into a 3/4 copper drain leading outside. When I replace the valve, would it be OK to connect to the existing drain with a flexible braided supply line, or would that not hold up if the valve released? Thanks--Brad

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

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    It would hold up, but would not pass codes or inspections because of its construction.
  3. Sponsor

    Sponsor Paid Advertisement

  4. MaintenanceMan

    MaintenanceMan In the Trades

    Dec 10, 2008
    Where I am at code does not allow for a T&P to be piped outside or under the house. Must be piped to at least 6" (IIRC) above the floor, termination visible from the appliance. I'd check your local codes.
  5. msgale

    msgale Member

    Sep 28, 2006
    the idea is that if the tp valve does blow off excess pressure, the resident will see it and be appropriately alarmed to take action. So it should be inside and visible,
  6. bsperr

    bsperr Member

    Apr 23, 2008
    Athens, GA
    That makes sense, because I didn't notice the weeping with the current drain only about an inch over grade outside...until it created a swamp.
  7. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    It also says it must terminate in a location which will not cause damage, and most interior locations would cause damage.
  8. kingsotall

    kingsotall Plunger/TurdPuncher

    Aug 17, 2008
    Hand copper part cleaned ready to go
    Flagstaff, AZ Sitting on an upside down 5 gallon b
    Not seeing t&p's piped to daylight always looks weird to me.
  9. jar546

    jar546 In the Trades

    Feb 20, 2008
    504.6 Requirements for discharge piping. The discharge
    piping serving a pressure relief valve, temperature relief valve
    or combination thereof shall:
    1. Not be directly connected to the drainage system.
    2. Discharge through an air gap located in the same room
    as the water heater.
    3. Not be smaller than the diameter of the outlet of the
    valve served and shall discharge full size to the air gap.
    4. Serve a single relief device and shall not connect to piping
    serving any other relief device or equipment.
    5. Discharge to the floor, to an indirect waste receptor or
    to the outdoors. Where discharging to the outdoors in
    areas subject to freezing, discharge piping shall be first
    piped to an indirect waste receptor through an air gap
    located in a conditioned area.
    6. Discharge in a manner that does not cause personal
    injury or structural damage.
    7. Discharge to a termination point that is readily observable
    by the building occupants.
    8. Not be trapped.
    9. Be installed so as to flow by gravity.
    10. Not terminate more than 6 inches (152 mm) above the
    floor or waste receptor.
    11. Not have a threaded connection at the end of such piping.
    12. Not have valves or tee fittings.
    13. Be constructed of those materials listed in Section
    605.4 or materials tested, rated and approved for such
    use in accordance with ASME A112.4.1.
    504.7 Required pan. Wherewater heaters or hotwater storage
    tanks are installed in locations where leakage of the tanks or
    connections will cause damage, the tank or water heater shall
    be installed in a galvanized steel pan having a minimum thickness
    of 24 gage, or other pans approved for such use.
    504.7.1 Pan size and drain. The pan shall be not less than
    1.5 inches (38 mm) deep and shall be of sufficient size and
    shape to receive all dripping or condensate from the tank or
    water heater. The pan shall be drained by an indirect waste
    pipe having a minimum diameter of 0.75 inch (19 mm). Piping
    for safety pan drains shall be of those materials listed in
    Table 605.4.
    504.7.2 Pan drain termination. The pan drain shall extend
    full-size and terminate over a suitably located indirectwaste
    receptor or floor drain or extend to the exterior of the building
    and terminate not less than 6 inches (152 mm) and not
    more than 24 inches (610 mm) above the adjacent ground
  10. theplumber

    theplumber Member

    Dec 20, 2008
    Are you totally positive that it's the T&P valve that's the problem and not your pressure regulator? Usually the T&P valve will leak before the Pressure relief valve since the hot side is under more pressure from the heat.

    Just something to check before you go and replace the T&P valve.

    You can also just cut the existing drainline well below the MIP going into the T&P valve. Unscrew put it back into the next T&P and reconnect using a Sharkbite coupling to put it back together. Depends on the codes for your state and local as to what you can use. If compression fittings are legal to use, u can get a brass compression coupling (not a g-coupling).
Similar Threads: drain
Forum Title Date
Plumbing Forum, Professional & DIY Advice Need advice for adding washer vent and possibly laundry drain Yesterday at 1:48 PM
Plumbing Forum, Professional & DIY Advice Pump for sink drain Thursday at 5:06 PM
Plumbing Forum, Professional & DIY Advice Sump pump drain pipe Thursday at 4:29 PM
Plumbing Forum, Professional & DIY Advice What is This Outdoor Drain? Wednesday at 12:27 PM
Plumbing Forum, Professional & DIY Advice Sink drain leak from overflow holes? Sep 13, 2017

Share This Page