Can any of you ladies and gentlemen help Hot water problem

[bluefox]

Hot water problem

:waving:My main problem is that the D H W keeps fluctuating hot and cold. I cleaned the small heat exchanger which did not seam to dirty.
In resent two winters I have changed the Dom & central heating thermistors the circuit board.
When the flame goes out in the hot water mode fault lights 50 70 80 I replaced the thermistor again in January and it did not change the fault.
I may not have done it good enough but the problem still exists I would be grateful for some help :drummer:

 

[jtsplumbing]

You need to call in a GSR to test gas supply ! could have undersize gas pipe or faulty govener on gas meater, as when running for hot water needs more gas.

 

[Roger Welton]

When you cleaned the plate hex did you used a acid baced descaler?

 

[bluefox]

Thank U the pipe is 22 mm Regulator is J42 type which seems Relatively newish

 

[bluefox]

Thank u I used Fernox sonic cleaner this may not have been strong enough

 

[ecowarm]

Sonic cleaner? BG use a machine to sonic clean H/E not aware fernox make a "sonic cleaner"

 

[bluefox]

Thank u I used Fernox sonic cleaner

 

[bluefox]

Thank you ecowarm I did not have machine for this could it be that it still needs cleaning? if I clean whole system with fenox would this be a better way forward

 

[ecowarm]

look here Cleaners they dont make sonic cleaner IMO

 

[jtsplumbing]

When running for hot water is the central heating pipe getting hot ? you may have a faulty 3 way valve, gets build up on shaft, easey to replace part No 1302411.