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. Multi-connection coordination: In a multi-connection system, the operation modes of multiple indoor units can be coordinated to meet the needs of partial cooling and partial heating. Refrigeration and heating switching: By changing the flow direction of refrigerant, the cooling function of the air conditioner in summer and heating in winter can be converted to meet the needs of indoor temperature regulation in different seasons. Stf-1511G Intelligent Variable Frequency Four-Way Valve, Weight: 0.110231131 pounds, Manufacturer: GENTERUN