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
What testing exactly did you do ? And when did you fit this immersion heater / element / thermostat ?
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.
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.
Is the bottom element showing those voltages during the daytime ? Is it connected to any timers / controllers or off peak meter ?
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.
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.
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.
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.