Heating Circuit, Function

Illustration: Engine 111:

Function
The coolant pump (4) pumps cold coolant through the engine (M). Here the coolant absorbs heat from the engine heating the coolant. Then the heated coolant flows through the heater core (6) where the heat is transferred to the passenger compartment air. The coolant quantity flowing through the heater core (6) is controlled by the duovalves (A31y1, A31/2) The coolant quantity can be controlled separately for the right and left sides.

The coolant returns to the coolant pump (4) via the coolant return (A). A coolant circulation pump can be installed in the return line between the duovalve and the coolant pump. The major portion of the coolant flows from the engine (M) to the coolant thermostat (3) and not through the heater. Depending on the water temperature the water flows through the radiator (2) or directly to the coolant pump (4).