Heater circuit, function - GF83.20-P-2003N

MODEL 215 

Fig 1: Heater Circuit Function Diagram - Model 215

Function 

The coolant pump (5) pumps cold coolant through the engine. There, the coolant absorbs heat from the engine and is heated up. The heated coolant then flows through the heater core (8) where the heat is transferred to the interior air. The coolant quantity flowing through the heat exchanger (8) is controlled by the duovalves (A31y1, A31y2) in the coolant return (A). The coolant quantity can be controlled separately for the left and right sides.

The coolant flows through the coolant return (A) back to the coolant pump (5). The major portion of the coolant flows from the engine to the thermostat (4) rather than through the heater. Depending on the water temperature, the thermostat allows the water to flow to the radiator (3) or directly on to the coolant pump (5).