Immersion Element

Discussion in 'Electricians' Talk' started by Martin Greshoff, Oct 11, 2021.

  1. Martin Greshoff

    Martin Greshoff New Member

    Hi
    I recently replaced my immersion cylinder and both elements. The tank & elements initially worked fine and the water heated up to the right temperature however recently the bottom element doesn't seem to be heating up the water to the correct temperature. I assumed it was the thermostat and replaced this but the issue remains. The water warms up over night but it is not hot enough.
    When I turn on the upper element one can hear the water heating up when the bottom one is switched on the sound is much quieter. The upper element heats the water to the correct temperature.
    I have tested the element using a multi meter and it appears to be ok.

    Before I drain the tank & replace the bottom element I wanted to see if there is anything I have missed or if anyone has any ideas on sorting this out.

    Many thanks
     
  2. Bob Rathbone

    Bob Rathbone Screwfix Select

    Bottom element is open circuit, bite the bullet, drain the tank and change it.
     
  3. terrymac

    terrymac Screwfix Select

    What testing exactly did you do ?
    And when did you fit this immersion heater / element / thermostat ?
     
  4. Martin Greshoff

    Martin Greshoff New Member

    It was fitted about a month ago. I tested for resistance between live and neutral, read about 20 ohms. I tested that there was current being supplied to element.
     
  5. terrymac

    terrymac Screwfix Select

    Testing Current supplied ???. Do you mean voltage ? If so what is the voltage measured between ......
    Live to earth
    Live to neutral
    Neutral to earth.
    If you measured resistance through the element ,with cables disconnected from the element, at 20 ohms ,then it's not open circuit.
     
  6. WillyEckerslike

    WillyEckerslike Screwfix Select

  7. Martin Greshoff

    Martin Greshoff New Member

    Yes by current I meant voltage
    Live to earth - 240v
    Live to neutral - 240v
    Neutral to earth - 0v
     
  8. terrymac

    terrymac Screwfix Select

    Is the bottom element showing those voltages during the daytime ? Is it connected to any timers / controllers or off peak meter ?
     
  9. Martin Greshoff

    Martin Greshoff New Member

    Yes, bottom element is showing those voltages with boost of the timer on so the element was live
     
  10. terrymac

    terrymac Screwfix Select

    Show us pics of exactly what both of these immersion heaters are connected to / controlled by.
     
  11. Martin Greshoff

    Martin Greshoff New Member

    The bottom element is connected to the timer and the top element to a switch- no timer
     

    Attached Files:

  12. bright_Spark

    bright_Spark Screwfix Select

    Could be a limescale build up at the bottom of the tank and the element is sat in it or beneath it. You need to drain the tank and look as well as clean it out if it is or replace the element. Either way it is the only remedy as you have replaced the stat.
     
  13. terrymac

    terrymac Screwfix Select

    The cylinder and immersion heaters are all fairly new
     
  14. bright_Spark

    bright_Spark Screwfix Select

    rules that theory out then. New element would be my remedy.
     
  15. terrymac

    terrymac Screwfix Select

    Very odd ,OP tells us electrically all readings ,voltages,and resistance are as one would expect them to be ,bottom element can be heard ,and does heat water ,but not as hot as it should.
    I wonder if the timer isn't energising for long enough ??
    If the element has failed ,it won't heat water at all ,and resistance wouldn't be 20 ohms.
     
  16. terrymac

    terrymac Screwfix Select

    Out of curiosity ,can you change the wiring / switch them over . So top element to timer ,bottom to other switch. See if it makes a difference.
     
    bright_Spark likes this.
  17. bright_Spark

    bright_Spark Screwfix Select

    It is a possibility but at this stage it is gong to become easier and quicker to swap out parts to rectify this. Can only be the element, timer or stat. I would start with the element first off to rule that out which is the hardest job done. Then look at the timer and work from there.
     
  18. bright_Spark

    bright_Spark Screwfix Select

    Good call.
     
  19. Martin Greshoff

    Martin Greshoff New Member

    I will look at the wiring to see if this can be done. The timer is is set for 3 hours
     
  20. bright_Spark

    bright_Spark Screwfix Select

    Is the top element going into your tank from the top or from the side at the top of the tank?
     

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