sounds like a problem i had with my old boiler. i renewed the safety blow off valve around the top of the boiler and all was fine ( for about a year anyway)
seasons greetings. I had a new boiler (ideal c28), pipework, rads etc installed recently and all worked fine untill this morning. no hot water & cold rads.
there is gas, water & electrikery to the boiler but it will not light. the pump feels a bit warm & turns freely. fuse on pcb is ok, water...