problem ..scalding hot water from electric water heater

Discussion in 'Water Heater Forum, Tanks' started by idreos, Dec 13, 2010.

  1. idreos

    idreos New Member

    Messages:
    6
    Location:
    Maryland
    I have a 60 gallon State Select electric water heater that is 4 years old.
    Recently it started putting out scalding hot water. I shut off the breakers and looked at the top and bottom thermostat and set both to the lowest temperature. It worked okay for two weeks,
    but the scalding water problem started again. Has one or both of the thermostats gone bad?
    Any other suggestions on what the problem may be? Thanks for you help
  2. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    The [lower?] thermostat contacts may be intermittently sticking closed. You'd need a temperature higher than the setpoint temp. to confirm this or you could gamble the price of a new 'stat and just replace it.

    I can't imagine what else it could be.
    Last edited: Dec 13, 2010
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,235
    Location:
    Cave Creek, Arizona
    As I stated elsewhere, a "failed" element can override a thermostat, and it is MUCH more common than a bad thermostat. (In 60 years I have changed thousands of elements and maybe a dozen or so thermostats.) In any case DO NOT start changing parts until you, or a plumber, diagnose the heater to determine the REAL problem, not what someone is guessing about. Otherwise you will spend a lot of money needlessly, and could still have the original problem.
  4. idreos

    idreos New Member

    Messages:
    6
    Location:
    Maryland
    Could loose circuit breaker cause the problem???

    When shutting the double breaker I noticed the breaker was loose on the clamp side..I shut main and fixed the loose clamp on the breaker..is it possible the loose breaker somehow caused the intermittent scalding water????
  5. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    I don't see how, but who knows?
  6. EdHitchens

    EdHitchens New Member

    Messages:
    4
    Location:
    Nova Scotia
    I have the same issue with our 4-year old Kenmore Power Miser 9 electric. Last Nov we had the Sears repair guy out to have a look and he seemed positive that the elements were fine and that it was likely one of the t-stats that was acting up. As we were able to reset the unit by flipping the main breaker and then pushing the red reset button on the heater, we postponed the repair while waiting to see if the problem would reoccur. Last week it did. My wife has now reached the "please fix this" phase.

    Is it difficult for a DiY'er to replace the t-stats? I can get the parts as they are covered by warranty but have no electrical or plumbing background whatsoever. Would I be better off paying the service tech to come back in (labor is not covered) or is this something even a guy like me (who has replaced a few household t-stats) could manage with a little caution and perhaps a little over-the-shoulder from someone with a clue? Thanks.
  7. idreos

    idreos New Member

    Messages:
    6
    Location:
    Maryland
    Ed, the replacement of the thermostat is easy. It took me less than 5 minutes. Are there two on that heater? You can tell if you have 2 cover plates on the side of the heater, one near top and one near bottom. If you do have two, past posters have indicated that its the one on the bottom that usually goes bad. The t-stat is unclipped from a mounting plate (after unscrewing/removing the 2 wires) and the new one snaps in and the wires re-screwed. THE MOST IMPORTANT THING IS TO MAKE SURE THE CIRCUIT BREAKERS FOR THE WATER HEATER ARE FLIPPED OFF BEFORE YOU ATTEMPT THE REPLACEMENT. I paid about $8 for a t-stat replacement made for my heater at home depot. Good luck!
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,235
    Location:
    Cave Creek, Arizona
    As stated previously, a bad element, usually the bottom, but could be the top one, is 100 times more likely to cause the problem than a bad thermostat. When that is the problem it makes no difference what temperature you adjust the thermostats to because it will still overheat. In any case the "scalding water" problem will usually go away fairly rapidly because the "safety override" should cut the power to the elements and then when you use the "hot" water from the tank it will NOT restart so then you have "freezing cold" water instead.
    Last edited: Mar 10, 2011
  9. idreos

    idreos New Member

    Messages:
    6
    Location:
    Maryland
    hj - thanks for the info!
    I went for the t-stat switchout two weeks ago and have had no problem since, but since the problem was intermittent every six weeks or so, I'm still crossing my fingers.
    Is the element replacement straightforward after shutting the breaker, draining the water, removing the element with a special socket wrench, and installing new one???

    What is usually the cause of an intermittent bad element?? Thanks for your input
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,235
    Location:
    Cave Creek, Arizona
    Elements are NOT intermittent, but what can happen is that they initially partially fail and cause the overheated condition, then go completely bad so they do not do anything. Either you have to feel the bottom of the tank to see if it is hot, or test the element to find out if it is operating, NOT just that it has "continuity".
  11. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,183
    Location:
    NW Ontario, Canada
    Now I could be off base here since I haven't worked on an electric water heater in decades and so don't know for certain how modern thermostats operate. If the thermostat switches only one of the leads of a 240V supply, the other leg would still provide voltage potential to the element. With 240V, there is no hot and neutral, just hot and hot. If the thermostat were double-pole, both hots would be isolated. Electric water heaters I've worked on all had single-pole thermostats.

    As long as the element is sound, there would be no alternate return path and the thermostat will control the temperature. If however, the internal electical resistance element is exposed to the water in the tank, depending on how much of the element is shorting out to the water and how conductive the water is, in theory at least, there might be enough current flow to continue heating the water despite the thermostat being open.
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