Perfect reply, thanks.
No idea why I posted the wrong diagram, I'd previously found the correct one !
All very clear now. Finally we can have a dammed thermostat instead of just on/off (Which due to laziness ends up meaning the house gets too hot or too cold constantly, wasting energy and...
Hi
We currently don't have a thermostat installed with out combi boiler, just the controller switch.
This is for heating only.
I'm looking to replace that controller with a Nest Thermostat and need to double check wiring.
I have attached wiring diagrams for hortsmann, nest & nest wiring for...