Worcester 350 combi boiler keeps shutting down?

My 11 year old Worcester 350 boiler will get to temperature and then completely shut down after approx 40 minutes. I then have to use the reset button to re-ingite the boiler. I have noticed that when the boiler is running, it is approx 1.5 bar, but when the boiler reaches temperature it shuts down and the pressure gauge will rise to above 3 bar and you can also hear a bubbling noise. Any help would be appreciated.
Carl Lockwood, February 2006


done
Paul, thanks for your answer. I called out Worcester and they managed to repair boiler, which included pump, pressure tank and fanassembly all for one call out fee of £185.00 inc vat. Carl.

Carl Lockwood, April 2006
pressure rise poss pressure vessel.if pressure goes up and up could be plate to plate heat exchanger.if cuts out when using hot water tap problem is hot water flow switch all in all may be better with new boiler . also had same problem and it was ignition board . its agood boiler but may be time t have new

paul, March 2006
link Click here to see other fixes for Worcester.