Where is the water valve of Porsche Maca heater?

Between the main engine water tank and the warm air water tank. According to Porsche official website, the water valve of Porsche Maca heater is between the main water tank and the heater water tank. The warm air water valve is the warm air switch of the automobile heater. The working principle of the automobile heater is that the radiator in the heater is connected with the circulating water of the engine through the inlet and outlet water pipes.