when running the hot taps - after a minute or so the boiler shuts down (ie no flames). If left the water runs cold then the boiler kicks in again and hot water returns for a minute or so, this repeats. It's been suggested to me that the problem is a diverter valve. The few plumbers/engineers I've asked don't want the work, seems they only fit new systems these days! They don't repair. I've found a manual on line but it seems to look totally different from my (possibly older) model. Any help available out there? System is filled to just over 1bar and water flow is 8 litres per minute.

Big Al, December 2008

sounds like scale in your plate heat exchanger, is your heating ok???

J, December 2008

i am not sure of the name of the part but i have had this problem before and am having it again right now ( engineer coming out tomorrow to fix it ) ,the problem has in the past been loss of pressure in a membrane (bag) inside the boiler ,it is there to allow for the expansion of water in the boiler .the engineer usually pumps it up with a car foot pump . job done !
Join the british gas care package and you wont need to worry any more ( i dont work for british gas )

maddog mcg, December 2008

thermistor or plate heat exchanger

b, December 2008