Basically, when I switch on heating, the timer is switching on both heating and hot water (to a tank). Both lights come on.
Oddly - I can switch on hot water independently - without triggering the heating.
I have taken off the timer and ensured it is switched to Independent control and Gravity system. Also the 3 way valve, heater thermostat and heating pump are all functioning as they should.
I have seen posts that suggest poor contact with the wall plate could cause issues like this - it is a much older back plate.
Does anyone have any other suggestions, or know of this issue?
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