Carrier Debonair 2 Owner's Manual page 7

Selecting the Heat or Cool Mode
Heat Only
Step #4 = 1 in the Advanced Setup section, page 11.
Heating Only
The HEAT setting indicates the temperature
that the room has to fall to before the heating
source will turn on to heat the room.
OFF
OFF indicates both heating and cooling
are turned off.
2-Pipe Operation
Fan
6
Press
MODE