My present thermostat Honeywell cm67 has 2 wires live and neutral. I want to replace it with a wireless one and wonder if I can just use the 2 existing wires to wire up the cm927 relay switch. I've looked at the wiring diagram for the relay switch but don't quite understand it. Do I just wire the brown to the L terminal and the blue to the N terminal? Mine is a standard non Combi boiler. Any help much appreciated.