Yes, if the valve does not open fully and engage the microswitch then the boiler will not fire
If the valve does not open fully when on hot water only the boiler may not fire
Follow the live backwards from the boiler, you could use a link between the live and boiler live and see if it fires
Thanks Andrew, will try and get back to you.
How did you get on?
Tried it and no luck. Even the Red live from controller to Red to boiler? I know the gas valve makes a noise when shutting off, but is it possible the valve at the solenoid end is faulty? All this from a blown fuse??? Lot of people confused...
It may have been the solenoid burning out that blew the fuse.