A/C Expansion Valve

The expansion valve is located just before the A/C evaporator and is used to regulate the flow of refrigerant that enters. It also drops the pressure significantly to cool down the refrigerant even more after it has left the condenser. Excessive refrigerant flow into the evaporator can cause evaporator flooding, resulting in diminished A/C performance and possible compressor damage. Alternatively, a lack of flow can cause evaporator icing.