The fan also overruns at low speed after a demand period. Thats from memory though, and I'll bow to the knowledge of any top 100 gas installers out there...
Remember, the flux capacitor requires 1.21 gigawatts!
OP, best advice is to get an RGI out to look at the appliance. Could be something as simple as the thermocouple, or as dangerous as flue spillage...
Well, as an ex BG fella, I'll side with PP here. I used to advise the client if their boiler was on the reduced parts list, and would ask them if they wanted a quote for a new boiler. It was made clear that there would be nothing wrong with sticking with the existing appliance for as long as it...