Hello I am not a plumber or heating engineer. I have the above boiler, and it starts sometimes and others not. When it does start, all radiators are hot and water is also fine. After a few minutes, it cuts out but pump and fan are still working then the heat drops off and everything goes cold. It sounds like it is overheating but not sure. I have had an engineer out but he can't get back to me till Wednesday this week. Pressure is at 1.5 bar so that's fine. Any ideas what the problem could be? Thanks Brett