Expansion Valve: Description and Operation

THERMOSTATIC EXPANSION VALVE (TXV)

NOTE:
- Installation of a new receiver/drier 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.
- A second (auxiliary) TXV is used for HVTB cooling on hybrid vehicles. For information concerning the auxiliary TXV, refer to Heating and Air Conditioning.

The TXV is located at the evaporator core inlet and outlet tubes at the dash panel at the 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.