Rheem Comfort Control2 Installer's Manual page 18

Aux Lockout Temperature
- Available
for heat pump systems. This feature disables the indoor
(electric or gas) heat above the selected outdoor
temperature. The temperature range is from the Heat
Pump Disable setting to 95°F.
Dual Fuel Setpoint:
If the heating system is a heat
pump with gas heat and the outdoor sensor is installed,
the thermostat can monitor outside temperature to
determine when to begin using the gas heat system and
stop the compressor. This temperature is the Dual Fuel
temperature setpoint. The Dual Fuel feature eliminates
the need for a fossil fuel kit.
The display will indicate 5° (default). The temperature
can be adjusted to a value between 5° to 50°. The
temperature will appear as °F unless °C is selected for temperature display.
As long as the outside temperature is above the Dual Fuel Setpoint, the compressor
will operate. When the temperature drops below the setting the thermostat will start the
gas heat and shut off the compressor.
18  Installer's Guide