Not sure if anyone can suggest any ideas. I had a new little unit (where you switch the heat/hot water on) fitted yesterday as the timer had broken but the boiler won't come on since :( I've done what I was told to get it on and read through the manual but no joy and they can't come out for days to have a look.
It was just that sort of issue that made me finally give up and join BG Homethingy last January. Can't rely on finding a competent available tradesman when you need one :-( so paying over the odds for the security of getting someone turn up seems viable.
You really need a handyperson who understands simple electrical issues. It is unlikely to be a major thing to correct, but impossible to diagnose over this sort of forum.