Electric WH T&P Valve

Discussion in 'Water Heater Forum, Tanks' started by gpdewitt, Mar 14, 2012.

  1. gpdewitt

    gpdewitt New Member

    Messages:
    21
    Location:
    Burbank, CA
    I want to install an electric water heater in an interior closet. Code requires a T&P valve discharging to a drain but there is no drain available and it's a long way to the outside of the building. Is there an electric water heater equivalent to the Watts 210 valve for gas water heaters?
  2. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    If no permit I would discharge into a 30 gallon steel container with a hole in the lid. I have never had a run away electric water heater in all my years, and most drips are just bad valves. For that matter you could set another "open" water heater next to it and discharge into the cold inlet. I see 40 gallon rigs for $199 now, and thats the cost of a few good garbage cans.

    That also gives you your next water heater ready to go.

    Running a pipe is a better idea, of course. And legal, if you care.
  3. gpdewitt

    gpdewitt New Member

    Messages:
    21
    Location:
    Burbank, CA
    Thanks, Ballvalve. I do care about legal. I've never heard of a runaway electric WH either. I've also been told there is safety circuitry built into them that prevents it. Still, the manufacturers and the code people must think there is a need for T&P valve, they both require it. I looked all over for an equivalent to the Watts 210 but for electric, seems like it wouldn't be that hard to make. Can't find one anywhere. Unless someone else has info on one, I'm going to conclude they don't exist.
  4. Hackney plumbing

    Hackney plumbing Homeowner

    Messages:
    1,174
    Location:
    Alabama
    Both gas and electric water heaters have a high limit ECO. (energy cut off).

    If you care about it being legal then I suggest either calling a licensed plumber and or your local plumbing inspector about the legal installation of an electric water heater in a location that has no suitable drain.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,503
    Location:
    Cave Creek, Arizona
    quote; I've also been told there is safety circuitry built into them that prevents it.

    When the water heaters started to come with ECOs, the plumbing codes in the Southern states believed the statement that it made heaters as safe as light bulbs so they did NOT require T&P valves. Subsequently, Domestic Engineering magazine had articles EVERY week about them exploding and destroying homes, AND people. One particularly disturbing one was a teenager who was sleeping on the other side of the wall when the heater exploded and decapitated him. Electric heaters DO go wild, and yours might be one that does it. How long do you think it would take a 3/4" pipe under full pressure to fill a 30 gallon barrel OR even a 40 gallon "empty" water heater? When first fill a heater it only takes a matter of minutes to fill it.
  6. Hackney plumbing

    Hackney plumbing Homeowner

    Messages:
    1,174
    Location:
    Alabama
  7. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    most all of those are fires, usually gas related. I would try and always avoid a gas water heater IN the home.

    No one suggests this guy not use a relief valve, its just about where to go with it.
  8. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,244
    Location:
    Land of Cheese
    Unless the water heater is on the 2nd floor, I can't imagine why running a drain line would be such a problem.
  9. Hackney plumbing

    Hackney plumbing Homeowner

    Messages:
    1,174
    Location:
    Alabama
    How do you plan to cross hallways or doorways with slab on grade construction.
  10. Hackney plumbing

    Hackney plumbing Homeowner

    Messages:
    1,174
    Location:
    Alabama
    I would install the water heater in a pan without a drain. Pipe it to a wags valve positioned in the pan. I would install the water heaters relief line into the pan. I would install another T&P valve at a lower operating set point at a higher elevation so I could install a gravity drain to the outside.

    Of course after pre approval from the plumbing inspector.
  11. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,244
    Location:
    Land of Cheese
    It's one of those questions that have different answers depending on where you are located.

    Where I am, there are no houses built slab on grade- only crawlspace or basement.
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