Dual HVAC Control Panel

The Dual HVAC system control panel replaces the standard sleeper control panel in Dual HVAC-equipped sleeper cabs. See Fig.. The Dual HVAC system is designed to maintain a comfortable temperature inside the sleeper, and can operate in combination with the cab climate control system when the vehicle is running, or independently when the vehicle is parked.

Fan Knob

Temperature Control Knob

PARK Button

Fig. 1, Dual HVAC System Control Panel

To operate Dual HVAC system, select a fan speed (other than off) and push the PARK button. Adjust the temperature control knob to the desired temperature.

The fan switch has ten fan speeds. Zero (0) is the OFF position. Turn the switch clockwise to increase airflow, and counterclockwise to decrease airflow.

The temperature control knob controls the temperature from 65°F to 85°F (18°C to 29°C). At the minimum setting of 65°F the unit will attempt to cool the bunk to 65°F and will not allow the coolant heater to operate. At the maximum setting of 85°F the unit will attempt to heat the bunk to 85°F and will not allow the A/C cooling to operate. In between the two extremes the unit will operate in either the heating or cooling mode to achieve the set point.

On vehicles with Optimized Idle, interior comfort mode with Dual HVAC system operates with the following parameters regarding the set point and comfort zone:

• If the bunk area reaches more than 10°F (5.5 °C) above the set point the Dual HVAC system immediately requests the engine to start for bunk cooling.

• Bunk area temperature 5 to 10°F (2.8 to 5.5°C) above the set point for over twenty minutes will cause the Dual HVAC system to request the engine to start for bunk cooling.

• When the sleeper area drops to more than 10°F (5.5 °C) below the set point, the comfort zone is exceeded and the Dual HVAC system immediately requests the engine to start for bunk heating.

• Bunk area temperatures 5 to 10°F (2.8 to 5.5 °C) below the set point for over twenty minutes will cause the Dual HVAC system to request the engine to start for bunk heating.

The mid-point position on the Dual HVAC system temperature control knob is a set point of 73°F (23°C). In most conditions the mid-set point for temperature and mid-set point for fan speed will assure a stable environment. Mid-point for both controls is suggested as the initial position, with subsequent adjustment for personal preference.