PX9700 and PX9900 activated by PIR occupancy detector. When activated, room temperature is boosted from background to comfort temperature for a pre-set period of time. Comfort temperature, background temperature and time delay selected on installation. User cannot adjust settings once installed. PX01001 touchpad activated. PX9900 offers additional level of setback (fixed at 5°C if room is still unoccupied after eight hours). Heating cannot be reactivated until current comfort period expires