Expansion Valve: Description and Operation

Expansion Valve - 2.4L & RHD Models:

An "H" valve-type thermal expansion valve (TXV) is used on 2.4L and RHD models. The A/C expansion valve is located at the dash panel between the liquid and suction lines and the A/C evaporator. The A/C expansion valve consists of an aluminum H-valve body with a thermal sensor and a fitting for the A/C low pressure switch.

High-pressure, low temperature liquid refrigerant from the liquid line passes through the expansion valve orifice, converting it into a low-pressure, low-temperature mixture of liquid and gas before it enters the A/C evaporator. A mechanical sensor in the expansion valve control head monitors the temperature and pressure of the refrigerant leaving the A/C evaporator through the suction line, and adjusts the orifice size at the liquid line port to let the proper amount of refrigerant into the A/C evaporator to meet the vehicle cooling requirements. Controlling the refrigerant flow through the A/C evaporator ensures that none of the refrigerant leaving the A/C evaporator is still in a liquid state, which could damage the A/C compressor.

The A/C expansion valve is a factory calibrated unit and cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.