Expansion Valve: Description and Operation

THERMOSTATIC EXPANSION VALVE (TXV)

NOTE: Installation of a new receiver/drier desiccant bag is not required when repairing the air conditioning system, except when there is physical evidence of contamination from a failed A/C compressor or damage to the receiver/drier desiccant bag.

The thermostatic expansion valve (TXV) is located at the evaporator core inlet and outlet tubes at the center rear of the engine compartment. The TXV provides a restriction to the flow of refrigerant from the high-pressure side of the refrigerant system and separates the low-pressure and high-pressure sides of the refrigerant system. Refrigerant entering and exiting the evaporator core passes through the TXV through 2 separate flow paths. An internal temperature sensing bulb senses the temperature of the refrigerant flowing out of the evaporator core and adjusts an internal pin-type valve to meter the refrigerant flow into the evaporator core. The internal pin-type valve decreases the amount of refrigerant entering the evaporator core at lower temperatures and increases the amount of refrigerant entering the evaporator core at higher temperatures.