How do I calibrate the room temperature sensor on the Rt20 RF thermostat?

To calibrate the temperature sensor, access parameter P03 from the thermostat's built-in parameters menu. Rotate the dial to increase or decrease the temperature, then press the button once to set the new value, which will then be used as the room temperature. Calibration should only be performed when the thermostat is not working normally, and avoid touching the thermostat cover or sensor head during the process. (Page 26)