Manual A/C-Heater Systems: Operation: Notes

When A/C is turned on, compressor clutch coil is energized, engaging clutch plate, actuating the compressor. Low pressure refrigerant vapor from evaporator is drawn in and compressed into a high pressure, high temperature vapor. As the vapor is pumped through condenser, vapor is cooled and condensed into a warm high pressure liquid. The high pressure liquid refrigerant leaves condenser and travels to the expansion valve. A restricted port in the expansion valve converts the high pressure liquid into a low pressure liquid/vapor as it enters the evaporator. The cold liquid/vapor refrigerant absorbs heat from air passing through evaporator coils in vehicle cabin. As refrigerant absorbs heat, it changes state back to a gaseous refrigerant vapor which is drawn away by suction of compressor to repeat the cycle.