Water Heater Dead ?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by johnnyd, Nov 16, 2006.

  1. johnnyd

    johnnyd New Member

    I was in the next room when I heard a pop from the electric water heater closet. The pressure valve on top was spraying hot water and steam. I shut off electric and turned off water at the heater. Is it dead ?:confused: What is the cause ?
    Thanks in advance.
  2. Verdeboy

    Verdeboy In the Trades

    It's not dead. It just got too hot or the pressure got too great.

    I'm no expert on this, so wait for the pros to tell you why this happened.

    But, I'll put in my 2 cents anyway. If you have a check valve or a pressure reduction valve, they could be malfunctioning, causing a build-up of pressure. Too much city pressure or well pump pressure could also cause the T&P valve to pop. If the problem is due to excessive pressure, The "cure" is usually to install a PRV and an expansion tank.

    I would dial the temp. down first and see if it happens again. Could be just a one-time thing. If your temp. doesn't get any colder, then one of your thermostats is bad.

    PS: Solsacre makes a good point, you should have a pipe attached to the T&P valve that leads to a floor drain, so you don't get all flooded out.
    Last edited: Nov 16, 2006
  3. solsacre

    solsacre Plumber

    Short answer: your Water Heater is probably fine.

    Long answer: If the t&p was spraying all over the water heater, I can assume that It is not piped outside or to a floor drain? Was the water coming out of the t&p? or around it?. If it's around it than it's probably your tank, but this sound more like it's coming out of it and it's not piped anywhere.

    The t&P is a safety device that is just doing it's job. :eek:

    One more question. Was the temperature scolding hot? If so it popped off because of excessive Temp. If not than it popped off because of pressure.

    Most of the time when water heaters "pop off" "stuff" gets in the t&p and they will not seal up, so your first step after panicking and cleaning up is to replace the T&P in most cases.

    Now... If it popped off because of temperature one of your t-stats have failed, or is not touching the tank. Replace both T-Stats just for the fun of it.

    If it is pressure, (you can test with a pressure gauge, some even have needles that will stay at the highest pressure obtained) than you can put in a PRV (pressure reducing valve ) it may-of been a one time spike from the city, it may be a failed check valve not allowing the water heater to "expand back into the service" any number of things.

    Oh, and run your Drain line outside. good luck

    Last edited by a moderator: Apr 27, 2010
  4. Gary Swart

    Gary Swart In the Trades

    Yakima WA
    There has been recent posts regarding the TP valve, rather than repeating them, I suggest you scroll down and find them. Find the ones discussing the need for an expansion tank in a closed system and see if it applies. Once the excess pressure is released, the valve is supposed to close automatically, but sometimes they are crudded up and don't. If the problem is just the TP valve, any hardware has them for $10-$15 and they're easy to replace yourself.
  5. johnnyd

    johnnyd New Member

    Thanks all.

    I opened (pushed down on) the valve and let it clean it self out. Tiny white specks came out. I Turned the water back on and it is not leaking. I just turned the heater back on and will wait to see what happens.
    If I replace the valve does it need to be soldered ?
    I am a newbie at this stuff.
  6. vaplumber

    vaplumber Guest

    Since you said steam was also spraying out, I assume the t/p valve was working as it should. Replace both upper and lower thermostats (abot $9 each locally in my area) and if that doesnt help, then replace both elements as well (also about $9 each here). Water heaters are simple, so nothing else should be causing your problem. For the cost, forget the testing and troubleshooting. Just replace the parts, and trash the old ones. Flush the tank out well, and get rid of as much of the lime as you can.
  7. johnnyd

    johnnyd New Member

    Will do. Thanks.

    Oh and the water temp is much higher then it was yesterday. I am unable to lower it .
  8. Cass

    Cass Plumber

    It is the thermostats not controlling the water temp like solsacre and vaplumber mentioned, replace both the upper and lower.

    The water temp rises over the temp allowed by the T&P release valve and it will open due to the water temp and or the pressure build up if you have a closed system, and let the water out.

    I would replace the T&P valve also while doing the stats.
    Last edited: Nov 17, 2006
  9. hj

    hj Moderator & Master Plumber Staff Member

    Cave Creek, Arizona

    You probably have a burned out element and it is bypassing the thermostat creating a runaway heater. It is overheating and popping the valve. We have a disagreement whether to test and repair the bad part or do the shotgun repair and change everything in sight. Some auto repair shops do the same thing. They start changing things and hope that eventually they fix the problem. If you use good parts, repairing the hot water heater can also get expensive in a hurry if you replace without testing.
  10. plumber1

    plumber1 Plumber

    Also......water hammer will weaken the spring and will eventually cause a spurt when the dishwasher or cloths washer stops filling. the next thing is a periodic drip. If it's been leaking then replace it.....
  11. solsacre

    solsacre Plumber

    ??? I have always understood that the Element can only do what it is told to do by the t-stat.

    Power goes through the T-stat. How can it go around? :confused:

    If the element doesn't shut off it's because the T-stat didn't tell it to.:eek:

    I am always interested in learning new ways to look at it. Any new bit of know-how is allways happly accepted.

    Last edited: Nov 18, 2006
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    New England
    Sometimes the contacts fuse together...
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