Temperature Control

Function
The temperature set with the temperature buttons is achieved and held constant by:
- Heating the air in the heater core
- Cooling the air in the evaporator
- Cooling and reheating (reheat mode)

Heat-up
The heater core heats up the air as it flows through and travels on through the air ducts into the vehicle passenger compartment. The heat given up by the heater core is regulated by the flow rate of the hot coolant through the duovalve.
Control of the duovalve is accomplished by the push-button control module (N22).

Cooling
The liquid refrigerant under high pressure expands as it passes through the expansion valve into the evaporator reducing the pressure. The refrigerant then evaporates. The heat of evaporation required for this purpose is taken from the air flowing through the evaporator. The cooled air then travels through the air ducts into the vehicle passenger compartment.

Reheat mode
The air which has been cooled and dehumidified by the evaporator is heated up again in the heater core. This prevents the windows from fogging up on the inside.