Carrier TC-NAC - Temperature Units

ADVANCED OPTIONS
Changing from Fahrenheit to Celsius
Your thermostat is preset to display the temperature in degrees
Fahrenheit. You can change this to Celsius.
1. Press and hold the mode button for about three seconds.
The display will show U7 and the letter F in the center.
2. Press the tip or down button on the right to change it
from F (Fahrenheit) to O (Celsius).
3. Press the fan button on the left to exit this screen.