New T&P leaks more than old one

Discussion in 'Water Heater Forum, Tanks' started by ThaDoctor72, May 10, 2011.

  1. ThaDoctor72

    ThaDoctor72 New Member

    Messages:
    3
    Location:
    Powell TN
    History:
    Bought a 1972 house with a 5 year old Bradford White 80 Gal WH.
    There is a PRV on cold inlet just above WH.
    There was no hot water when we moved in, so first thing I did is replace a bad lower element. After replacement, the red cutoff button on the top t-stat pops out after a few hours. (There is no temperature dial on the top element, only the bottom)

    Issue:
    The old T&P pushed out a 2 gallon bucket of water per day.
    I replaced it with a typical 150psi valve this afternoon. The power to the WH has been off all day since this morning.

    In the last 6 hours, the new T&P has let out 14 gallons. (room temperature) OMG I HATE WATER!!

    Other notable plumbing attributes:
    This is a 5 br house with basement, 3.5 bath, and the hot water trickles while the cold has about 55psi. Copper pipes, and there is no expansion tank in the line. I've reduced the PRV and still no change.
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,309
    Location:
    Cave Creek, Arizona
    You may have one problem or several. You have to determine WHY the reset popped out. I have NEVER seen a thermostat, top or bottom, which did NOT have temperature settings. Have you checked the ACTUAL pressure in the house to determine if the PRV is defective or not?
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,824
    Location:
    New England
    Install an expansion tank first, then see if the T&P stops leaking. Once you have an expansion tank in the system, get a pressure gauge and check things. Doing this first will only confirm that you have an expansion problem that is causing the T&P to dump water. Then, if you have hot water leaks elsewhere, those will just make the problem worse since the WH will need to run more often to reheat the incoming cold water, creating more expansion, and more discharge.
  4. DonL

    DonL Jack of all trades

    Messages:
    3,819
    Location:
    Houston, TX
    I have seen Water heaters that are Controlled by 1 thermostat, And have two elements.

    The rating of the new element, may be overloading the old cut off. Could be the other element is shorted.
    But there is some reason that it cut out.

    When You heat water, It expands and the extra volume has to go somewhere.
    You would think a expansion tank would be a requirement, If it is on a city Water Supply.

    If it is on a private water well, then the Water tank may be waterlogged.


    ThaDoctor72, Welcome to Terry's Forums, Good Luck on your project.

    Have a Great Day.


    DonL
  5. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,309
    Location:
    Yakima WA
    Sound like either no thermal expansion tank or a faulty one.
  6. ThaDoctor72

    ThaDoctor72 New Member

    Messages:
    3
    Location:
    Powell TN
    Thanks for the input. I will install an expansion tank this weekend and update. I've been wanting to install an interior master cutoff valve anyway, so this will give me a reason to use these new SharkBite fittings.
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,309
    Location:
    Cave Creek, Arizona
    quote; The power to the WH has been off all day since this morning.

    Without power there is NO thermal expansion so that cannot be the cause of the T&P valve discharging.

    Quote; I have seen Water heaters that are Controlled by 1 thermostat, And have two elements.

    IMPOSSIBLE unless the elements are so underpowered that they could not overload the circuit, and then it would be impractical, plus it would have to be the upper thermostat to control it properly. I have never seen or heard of ANY heaters wired that way. OVERLOADING the circuit would trip the circuit breaker NOT the thermal high limit which only responds to excessive temperature.
  8. DonL

    DonL Jack of all trades

    Messages:
    3,819
    Location:
    Houston, TX
    You are correct hj about it would have to be the top element with the thermostat, to work properly.
    Water heaters wired that way are very Old School, Lower Current Elements. Slow Recovery time also.

    As for the high temp cutout tripping, Because of bad element, This is the theory, that makes the water overheat;

    A bad element that is shorted to ground near the center of the element may also cause the water in the tank causing the ECO to trip. Because the element is shorted to ground near the center of the element the short does not have a high enough current draw to trip the circuit breaker and it continues to heat. However, the way the water heater electrical power is switched the power still is applied to the element even when the thermostat shuts off. The water heater is supplied with 240-volts which means both of the power leads are hot leads. Only 1 side is switched and in normal operation that is fine. But, when the element is shorted to ground there is still the power on the UN-switched side available, which will flow through half of the element to ground as 120-volts continuing to heat the water until the ECO trips.

    As for the Power being Off and still leaking, Don't make sense. Maybe something else is tied into that drain, and the water is coming from something else.

    Have a Great Day.

    DonL
  9. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    You have several problems.

    1st with the water heater off and still leaking you have a pressure problem or, the new T&P is defective. Measure your pressure to see if the PRV is working.

    The second problem is with the water heater over temping which needs to be troubleshot to find the problem.
  10. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
  11. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    Except the pressure scale doesn't go high enough for a potable water system...

    And the temperature scale goes way too high...
  12. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,309
    Location:
    Cave Creek, Arizona
    quote; Water heaters wired that way are very Old School, Lower Current Elements.

    It would have to be VERY "old school" since I go back to the 50s and they have not been wired that way since then, and ANY heaters which MIGHT have been wired that way have rusted out and leaked a long time ago.
  13. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    Quick link. Look more for several other versions with higher pressures.
  14. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,309
    Location:
    Cave Creek, Arizona
    quote; If code made every heater have this gauge, we would all have much less to talk about

    All the gauge would do is MAYBE isolate the symptom, but we would still have to discuss what the problem is that caused it.
  15. ThaDoctor72

    ThaDoctor72 New Member

    Messages:
    3
    Location:
    Powell TN
    Problem resolved.

    Turns out, the pressure in the house was 160psi.
    The PRV was attached to the cold inlet on the water heater, which is fine apparently, if you want to regulate only the hot water. I installed a PRV and internal ball valve (for convenience) on the main incoming line, and now we're down to 60psi. Took a nice hot shower and enjoyed every minute of it.

    Now, I've noticed that I can push my faucets in the middle position and get nice hot water, without having to have them in the 95% hot position. After some tweaking, hot and cold are now the same pressure. While I was at it, I also installed a new thermostat/cutoff switch on the upper element so now I can control that one as well. They are both on the lowest position possible, and the water is very comfortable for everyone.

    And I can say I LOVE those gator-bite/shark-bite fittings, they really stand up to the pressure and they are a pleasure to install. (except if you are in close quarters and don't have much horizontal play in your copper piping.) They want a whole 1.5 inches in the sleeve, but it was REAL simple. Totally recommend for someone who despises soldering. Kinda pricey though, but with the time it saved, it was worth it.

    Thanks to everyone for their input. Without the right tools, (pressure gauge) it's really hard to diagnose anything intelligently.
  16. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    In that case the PRV installed on the water heater was bad but it is no longer needed.

    In addition you still have an undiagnosed problem with the ECO (red button) which will return again.
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