the controller for my combi-boiler was inside the airing cupboard and I relocated it to a more sensible location. wired up 2 cables (white) as they were. had to extend the 3rd cable(grey) as it was too short. all works fine except the central heating. the timer/thermostat activates on controller but the radiators dont heat up.
I realised that the hot water needs to be turned on as well for the central heating to work.
I have double checked the wiring but dont understand the 123456 on the inside of the controller. need to understand which cables control which, esp the grey which I extended.
Pls help! many thanks for any ideas or tips!!