Thinking of getting a Drayton wiser thermostat and trv kit to replace my old one. It’s a combi boiler which is Opentherm compatible, is it better to use this for control than the normal method, and if I’m using Opentherm do I just have the 240v power to the wireless receiver then only the low voltage Opentherm connections to the boiler (so no 240v switched CH demand wires from the receiver to the boiler?)

Edit – I do have boiler installation manual somewhere which gives wiring details and I’ll read them before fitting but having a quick look on the Drayton site it wasn’t clear if you used only the low voltage wiring!

Thanks

On mine the 240v thermostat contacts on the boiler is bridged with a small wire, the boiler is set to OpenTherm mode and the low voltage wires connected. The WiserHub needs powering from 240V, which you can take from the boiler or from elsewhere.