Refrigerant shutoff valve at front and rear

The rear automatic air conditioning (HKA) is connected to the refrigerant circuit of the integrated automatic heating/air conditioning system (IHKA) and is supplied from the same air conditioning compressor. The two refrigerant circuits are separated by 2 refrigerant shutoff valves (front and rear) which are only fitted together with the HKA.

The front refrigerant shutoff valve is integrated in the expansion valve of the IHKA and it blocks the pressure line to the front evaporator. The rear refrigerant shutoff valve is integrated in the expansion valve of the HKA and it blocks the pressure line to the rear evaporator. The connection and control operation of the HKA for the refrigerant circuit of the IHKA is designed in such a way that independent operation is possible. If both systems are in operation, pulsing the 2 refrigerant shutoff valves can regulate both systems independently of one another. However, at least one refrigerant shutoff valve must always be opened. The HKA control unit activates the refrigerant shutoff valves (front and rear). Without current, the refrigerant shutoff valves are closed.