A little while ago I noticed my CH wasn't coming on when it was programmed to, nor would it come on when turned on manually but pretty sure the pump was still running. It would work more often than not so it wasn't a major concern then. Hot water side is fine and will always deliver hot water when it's called for. Now what I'm getting when I want the CH on is that I'll get the light come on to tell the boiler it's calling for heat, then the flame light will come on then hearing a clicking sound (coming from the direction of the diverter valve) then the lights go out with no heating although it sounds like a pump is running. I've put the boiler in high fire mode (unsure if that's correct tech talk shown on last picture) where the boiler will fire up and heat the rads.
This is the set up
I did call someone out who tried another diverter valve (the top plastic part) and it did the same. They put it down as the Towerstat RF set up needed ditching and they'll replace it with a Hive set up. Firstly would the Towerstat cause this to happen as I can't help thinking it may be the brass part of the diverter valve is the fault or both or could it be something else?
This is the set up
I did call someone out who tried another diverter valve (the top plastic part) and it did the same. They put it down as the Towerstat RF set up needed ditching and they'll replace it with a Hive set up. Firstly would the Towerstat cause this to happen as I can't help thinking it may be the brass part of the diverter valve is the fault or both or could it be something else?