Hi, I have currently a mechanical thermostat (honeywell) which I would like to replace with a slimline, flushmounting thermostat (RMT230D).
However I am a little confused by the wiring diagram.
The boiler connections are L1, L2, Earth, Neutral, and L3. Per the wiring diagram for the boiler, L1 & L2 are connected at the boiler end. Currently, there are two wires to the thermostat, and these connect to L1 & L3 on the boiler.
Wiring for the RMT230D shows 5 connections. NC, NO, COM, L & N.
L & N on the stat connect to L2 & Neutral respectively on the boiler. Earth on the boiler gets earthed to the backbox.
I am thinking L1 connects to COM, and L3 to NO (as NO is labelled "on" in the diagram). So what connects to NC (labelled "off" in the diagram)?