fitting new Ch programmer

[mercedesjb]

have replaced my Landis & Gyr RWB200 CH programmer, with a Myson 2MEP 2c Dual programmer

All the settings are correct on back I.E. 'I' '7' (5/7 day) and 'P' for Pumped.
however when powering up, both CH and water came on , but no display?
non of the buttons did anything?

with mains switched off again after removal, i noticed that there wasnt a cable going to terminal 2 on the existing wall plate?
according to the user manual for the myson-this should be for CH off?
I have now put the original programmer back.

the question is, will this Dual programmer work on the original wiring?

 

[corgiman]

unless you have a power on poweroff head you dont need to connect tot he CH off terminal and most valves return via spring