Hi, I have just bought a Drayton Digistat+ room thermostat but i am having trouble understanding how to wire it up, as my system has never had a room thermostat i have to start from scratch with the wiring, my timer control is a Landis and Gyr Rwb200. The connections on the stat are:-

1: Heating Satisfied
2: Call for heat
3: Common/switched live from time control
4: Negative (not required)

Any help would be greatley appreciated.