I have the above boiler, its keeps cutting out and have to press restart button, tried a lower heat setting no joy, have replaced thermostat and overheat stat problem still persists, do get a noise from the boiler which sounds like a kettle boiling believe this is known as kettleing.Ten years or so ago change both the both fan and mother board have been changed
any ideas

Graham, June 2009

You have scale in the boiler heatexchanger
Scalebraker from fernox should reduce the scale in the boiler, double the does up. it need to circulate to boiler to break it up.
If unsucessable than powerflush the boiler will improve the system.

Mr K, June 2009