I bought a house that has a BMPlus 2000 control unit to modulate the dampers between the main floor of the house and a bonus room over the garage using a single heat pump. The current thermostats are Honeywell (T8400C 1024 (2) 0016 1A on a tag inside). The housing is a white square with a small square window showing temperature with "set" in the lower left, and "room" in the lower right. The the right of the window are raised arrows (up and down) for changing the set point. The lower left of the unit has a FAN/auto and on switch, and a SYSTEM cool off heat switch. There are only 4 wires going to the thermostat: W Y G R vertically. Note: BOTH thermostats are identical and each have only these 4 wires.
I would like to replace these two thermostats (one on each floor) with identical setback thermostats so I can go on cheaper "time of day" pricing with my electric company. What thermostats would serve this purpose and work with the BMPlus 2000? I would prefer to NOT have the emergency/backup heat come on to get rapidly back to set point AND I'd prefer the thermostat/BMPlus 2000 combination to NOT anticipate the end of setback. I do NOT want any power to be used over the setback period unless the set temperature is triggered. IS THIS POSSIBLE???
Thank you for your help