Ensure the refrigeration cycle: In the refrigeration mode, the refrigerant is fed from the compressor to the condenser, and then sent to the evaporator through the expansion valve to absorb the indoor heat and reduce the indoor temperature. Safety protection: When the system has abnormalities such as high and low pressure imbalance, cut off the refrigeration circuit in time to prevent compressor liquid shock and system damage. Adjust the flow of refrigerant: The flow of refrigerant in the system can be adjusted to control the cooling or heating effect and accurately adjust the indoor temperature. Solenoid Four-Way Valve Stf-3001G Central Air Conditioning Four-Way Reversing Valve, Weight: 0.110231131 pounds, Manufacturer: GENTERUN