Electric Hot water on Demand issues

Discussion in 'Water Heaters and Softeners' started by Damien Cochran, Sep 17, 2018.

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  1. Sep 17, 2018 #1

    Damien Cochran

    Damien Cochran

    Damien Cochran

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    Here at work and we have a little electric hot water heater. It had been sitting for a while but I just installed it because the old identical one just died. I properly installed this one and it worked great for 4 days. Today it’s having issues.

    If you let it sit with it’s 2.7 gallon tank. It will heat the water in it from cold to its set temp at 110 in about 1min 15 second. Slow right? I thought so too. How ever I de-energize the unit just a minute ago and see it has 10 ohms of resistance..... Sooooo why? It’s getting 120vac like it should. It has good resistance. The thermostat is saying it needs heat and it is heating just very slowly. This screams needing a new element but am I missing something? Thoughts?

    The excate model I have is a: Bosch Tronic 3000T - 2.5 model. Thank you for any information on this!!
     
  2. Sep 18, 2018 #2

    Geofd

    Geofd

    Geofd

    Professional Professional

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    I just installed 2 4 gallon bosch heaters....I put one under a kitchen sink....there was hot water there already....just not hot (the bld hw heater is under sized) and there is no return....so I fed the heter with bld hot water....its working fine the second feeds a small commercial dishwasher....(with a booster) so it seems to be fine also...do you think there may have been air so the elements may have effected?????
     
  3. Sep 18, 2018 #3

    Jamesplumbing06

    Jamesplumbing06

    Jamesplumbing06

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    That small a tank you have 1 element. So it either works or it doesn’t. I just timed a 2 gallon pot on stove to steaming. Took about 2.5 minutes. Now if you want “on demand” hot water then you get a heater made for that with a aerator to slow flow down to .5 gallon per minute. So even then your heater that’s designed to be on demand only heats up .5 gallon per minute. 2.5 gallon at 110v plug and play. you stated took 1 minute to heat. You will run out in a minute with normal aerator of 1.6 gallon per minute. We aren’t electricians for the most part. So an ohm reading while heating doesn’t tell us much. We ( for the most part) know that a element either works or doesn’t. A thermostat can stick but thermostat doesn’t restrict electric just directs it. But I think a minute to heat up 2.5 gallons is pretty good. Your getting close to the capacity of a double 220 with 30 amp on demand heater. Those do about 3.5 gallon per minute. If the heated water just isn’t lasting long enough. Then check the aerator. Pot smokers steal the screens to use in their smoking pipe. This opens the water flow up and will drive the maintenace man nuts. If this sounds like jiberish then you might try same question on an electrician or engineering forum. Good luck and god bless.
     
  4. Sep 18, 2018 #4

    FishScreener

    FishScreener

    FishScreener

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    I did the calcs, and for the Ohm reading you gave, and 100% efficient heat transfer: I’m getting about 23-minutes to heat 2.7-gallons 60-degrees.

    So I’m really confused.
     

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