low voltage and leaking electric heater

Discussion in 'Water Heaters and Softeners' started by kholmes123, Jul 21, 2018.

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  1. Jul 21, 2018 #1

    kholmes123

    kholmes123

    kholmes123

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    Hi. Can anyone let me know if I am way off base? I have a Rheem electric water heater that is over a decade old. It no longer provides any hot water. When I opened the upper panel and measured the voltage (touching the two terminals under the plastic cover), my digital multimeter showed only 80V. In addition, there is water on floor and the insulation itself is dripping water from the control panel. Is this heater likely totally done? I tried to measure the voltage directly on the terminals for the upper element instead sticking inside of the lugs on the top of the unit (I didn't pick up any voltage when i tried to do that). Thanks for any additional tips.
     
  2. Jul 21, 2018 #2

    fixitron

    fixitron

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    The low voltage that you are measuring is the voltage drop across the heating element. The proper way is to turn off the breaker, disconnect one wire from the lower element, measure the resistance across the two screws on the element. If it reads around 12-14 ohms, the element is good. Now check the ohms between each screw and ground. It should be infinity. Next, do the same with the upper element. (The lower element does most of the heating. The upper element only comes on when the upper thermostat detects cool water, such as when you have used up most of the hot water in the tank.)
    With the elements disconnected and the disconnected wire protected from shorting (such as by capping with a wire nut), you can now measure the voltage to either the upper or lower element, depending on the temperature in the tank.

    If the insulation is wet and it is fiberglass, it is more than about 15 years old and it is leaking. It it is leaking at a connection, such as at a heating element, then the threads are likely too rusty to try to stop the leak. Time to replace the heater.
     
  3. Jul 21, 2018 #3

    Mr_David

    Mr_David

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    Replace it
     
  4. Jul 22, 2018 #4

    kholmes123

    kholmes123

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    Hi. I am shopping now. But in meantime I’d like to better understand. I thought the top two terminals are the ones to check voltage when power is on and resistance when power is off? They are not? I uploaded a photo
    FFEE7CD6-8D18-41C8-8331-FC07D290950F.jpeg
    When I used my digital meter with power off I think the resistance was less than 1 ohm. Is it possible I have a short across the heating element?

    I also noticed that there is water seeping out from the area around the element. When I pressed a piece of attached plastic, rusty water bubbles out.

    Can the water leak be related to voltage/resistance?

    Is there any value to trying to replace the elements and thermostats based on your eprofeasional or personal experience?

    I know I’m about end of life but would prefer to not be in emergency mode if I can spend the rest of the day doing a simple maintenance. And I’d like to better understand what’s going on for future reference.

    Thanks!
     
  5. Jul 23, 2018 #5

    kholmes123

    kholmes123

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    Oh, and I noticed that the tank now has some hot water in it. So something may have been addressed as I was checking connections and such. So if I could deal with the leak I met get a little more use out of it while I shop for the ideal replacement. I'm considering tankless but want to do more research on installation costs
     
  6. Jul 25, 2018 #6

    Mr_David

    Mr_David

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    Don't really understand why so many people think tankless is the better way to go.
    True they take up less space BUT most tank heaters are installed, then you forget about them.
    Tankless require more periodic maintenance.

    I have never seen any test instruction in regards to checking an element for a specific number of ohms.
    To test an element with an ohm meter you have to disconnect both wires from element.
    meter probes - one on each element terminal -
    ANY reading = good element.
    No reading = bad element.
    touch on probe to one terminal and the other to head of element or even the tank;
    any reading and element is bad. same with other terminal.

    when testing power to upper stat you should get 200 to 250 volts when you touch voltmeter probes to both top terminals.
    or half that when you touch one terminal and the other to any ground ( tank ).
    you should have 2 breakers ( double throw ) power panel unless you only have a 120 volt heater.

    If you're only getting 80 volts turn off breakers and disconnect lines from terminals.
    Then check each one separately to ground ( tank ) with volt meter. you should get 110 - 120 volt on each wire individually.

    I found and old State WH service manual. Not all thermostats are the same as far as terminal layout on stat.



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    Last edited: Jul 25, 2018
    TomFOhio likes this.

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