We have a 2-zone installation with the following equipment: Furnace: U96VA (2-stage, communicating) Condenser: UA17 (2-stage, communicating) Zone Control: EWC Ultrazone Zone Dampers: EWC Rectangular ND with MA-ND5 actuator Thermostats: Econet UETST700SYS (Main Control/Downstairs Zone 1 ...