Evaporator Core: Description and Operation

Fig.5 Evaporator Coil:

A/C EVAPORATOR
The evaporator coil is located in the heater-A/C housing on the passenger side of the vehicle. The evaporator coil is positioned in the housing so all the air entering the housing passes over the evaporator fins then through the system ducts and outlets. Air passing over the evaporator fins will only be conditioned when the A/C system is on. The evaporator coil cannot be repaired and must be replaced if faulty or damaged.

Refrigerant enters the evaporator from the expansion valve as a low-temperature low-pressure mixture of liquid and gas. As air flows over the evaporator fins, humidity in the air condenses on the fins and heat from the air is absorbed by the refrigerant. Heat absorption causes the refrigerant to boil and vaporize. The refrigerant becomes a low-pressure gas before it leaves the evaporator.