Replacing room Stat

[springer11]

My old room stat is a Drayton RTS 1 -it has 4 wires
1 = blue - neutral -- 2 = red live -- 3 = yellow /red call for heat --- 4 = earth yellow

New stat is a Honeywell DT 90 E -- it has three connections
a = live -- b = neutral -- c = ????? ( shows wire linked to a via switch )

Any idea which wire is connected to c -- is this the call for heat connection ?

 

[Tibbot]

You only use the lives. There is no neutral or earth connection which s/be made safe.

 

[Dan Robinson]

See is used for cooling applications. ignore it.

 

[springer11]

You only use the lives. There is no neutral or earth connection which s/be made safe.

So therefore 1 red goes to A = Live on Honeywell DT90E
that leaves me with 1 yellow / red = call
i assume that this is the other live and goes to connection marked b = neutral on the Honeywell

Thanks for your help