508144-01
Page 24 of 42
Issue 2128
Thermostat
Install the room thermostat according to the instructions provided with the thermostat. See Table 7 for thermostat designations.
If the furnace is being matched with a heat pump, refer to the FM21 installation instruction or appropriate dual fuel thermostat
instructions.
Indoor Blower Speeds
1. When the thermostat is set to “FAN ON,” the indoor blower will run continuously on the low speed when there is no
cooling or heating demand. See Table 16 for allowable circulation speeds.
2. When the unit is operating in the high-fire or low-fire heating mode, the indoor blower will run on the corresponding
heating speed.
3. When the unit is operating in the low cool or the high cool cooling mode, the indoor blower will run on the corresponding
cooling speed.
045-12
070-12
090-12
090-16
110-16
110-20
COMFORT SYNC
®
THERMOSTAT
Figure 32. Wiring Diagram