dhw switching off and on Information, help and advice on many gas related subjects from gas fires to domestic appliances

[furry]

Hi all i have a ferroli domi f24b only 18 months old and the hot water switches off and on. ie when it hits preset temp no matter what you set it to the flame goes out and when it cools down fires back up again!!!
this problem happened from new and someone told me to turn cold feed pressure down and it worked and its been fine untill i switched the central heating back on could it be a pcb fault? has anyone come across this before?
central heating working fine infact the dhw seems to mimic the heating side modulating the same way any help would be appreciated

[da pickles]

[quote="furry"]Hi all i have a ferroli domi f24b only 18 months old and the hot water switches off and on. ie when it hits preset temp no matter what you set it to the flame goes out and when it cools down fires back up again!!!
this problem happened from new and someone told me to turn cold feed pressure down and it worked and its been fine untill i switched the central heating back on could it be a pcb fault? has anyone come across this before?
central heating working fine infact the dhw seems to mimic the heating side modulating the same way any help would be appreciated[/quote]
if your boiler is over rated [burning to much gas] then the boiler will fire then upon reaching desired temp finds it cant modulate quick enough and safety stat kicks in until temp has dropped. sounds like the boiler needs recommissioning