Hi . this is an issue with either a sludged domestic heat exchanger or hot water thermistor/temperature stat. Replace the stat first as its fairly cheap , if problem continues , clean or replace the domestic hot water heat exchanger
please can you tell me which number on the diagram is the thermistor
is it the same as flue safety NTC?
or is it NTC sensor or Overheat thermostat? because my manual is showing these three as three separate parts
Hi , its not on that diagram , give me a few mins thanks
Hi , its an NTC shown on page 43.
is it the one on diagram 14.12?
Not sure we are onbvtge same page. If you go to page 43 it shows it there .it doesn't show it on the page you pasted in
this is my manual
Hi , I have the same one . it is shown clearly on page 43
Thank you - will this solve the digital display to match the temperature of the water because only the display temperature rises the water doesnt get hot?
Thank you i appreciate your clarification on this matter
, I think the fault is probably the Dom heat exchanger . when it gets a little blocked the water can't get through fast enough so the boiler ( on full heat ) gets up to temp quickly, then overheats almost straight away turns off , then cools , back on again etc . you end up with the hot water going hot then cold . if you feel the Dom heat exchanger while its doing this you will feel this happening. Have to let you know about the hot water temp sensor as well as. This an sometimes give similar fault
Yres it will solve the display
is the Dom heat exchanger on page 45 FIG87 14.8?
Yes its the rectangle looking thing . has a waterway for the heating boiler water and a waterway for the cold water( comes in cold , heat is passed on through narrows fins , comes out hot , or should do
Some boiler guys clean them out but I find once they start to scale/ sludge they are never the same
what is your recommendation to order the sensor?
do i need to order it online or is it easily available in a plumbing shop?
The sensor is about 30 pounds easy to replace( turn off cold , unscrew and replace.) The heat exchanger is a bit more difficult but doable , especially when you have a bit of time
I am happy to rate your service as excellent thank you for the advice
Readily available at good plumbing shop/ boiler spares
No probs , would you mind rating your answer? Thanks
i am doing it now :-)