Looking for a better Thermostat to replace a Honeywell Chronotherm III (early 90s) which thinks it is controlling a simple heat pump, not a dual fuel system. The system is a heat pump (Carrier 38BY030300), 80% eff. oil furnace (Armstrong Ultra 80 L6B84/95C12-5A) but no heat strips. There is an external bulb thermostat which sets the crossover temp. between HP & furnace.
Here's how I want the system to fucntion:
Set back 10 deg colder at night
Temperature to be at setpoint within 10 minutes of scheduled time
Furnace to handle large temp. cahnges - if too cold for HP to accomplish in reasonable time
HP to maintain temps - even when very cold
Furnace to run only a few minutes when HP goes into defrost
Cold air blowing when HP defrosts
HP to come on so early (> 2 hours) in the morning in order to get to set point. Pros/Cons?
Considering using RobertShaw 9720i or 9870i, and White-Rodgers 1F95-371 or 1F95-377. Wondering if de-humidification option on 9870i is worth the extra $.