Ok guys - actually a Bath Ales Gem and a comment on another forum jogged memory. Browns to Common and 1. Blues Chocked. Earths which were connected to earth on CS1 now chocked. Now works as before. However it is an interesting configuration and I will get in an engineer to look the whole lot...
Thanks for the prompt replies.
I will chock the two earths together - as before.
I am assuming in which case that I connect both brown wires to the Common terminal and the two blue wires to the Call (1) terminal. Although not sure it makes any difference which way around.
I am replacing an non-functional Drayton CS1 Cylinder Stat with a Drayton HTS3.
The Cylinder Stat actuates an ACL Lifestyle two-port motorised valve.
The wiring on the old configuration was just Live (brown), Neutral (blue) and Earth (Y/G) - both from the 'wall' to the Stat and from Valve to...
