Fitting an RF T'Stat to Worcester 240

[metalmick]

Hello to all first and thanks in anticipation,

I have moved to a new property (to me) and there is a Worcester 240 fitted, it works well so no plans to change it but there is no T'stat fitted in the house,

I have aquired a horstmann wireless stat to use;

I have down loaded the wiring diagram for the boiler and it shows the terminal block with 1 & 2 to stat, 3=N , 4 & 5 = frost stat.
so far so good,

Now Ilook at the diagram with the stat and here lies the confusion. is it to be run as volt free? how do I know,

The main supply is the same and so sorted,

If any more info needed, I can scan and post up the diagrams if wanted.
Mike