RAM 2500 Van V8-5.9L VIN Z LDC (2000)
Expansion Valve: Description and Operation
Rear
Models equipped with the optional rear heater-A/C unit have a second "H" valve-type thermal expansion valve (TXV) installed between the rear unit
liquid and suction lines, and the combination coil. High- pressure, high 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 combination coil.
A temperature sensor in the expansion valve control head monitors the temperature of the refrigerant leaving the combination coil through the suction
line, and adjusts the orifice size at the liquid line to let the proper amount of refrigerant into the combination coil to meet the vehicle cooling
requirements. Controlling the refrigerant flow through the combination coil ensures that none of the refrigerant leaving the combination coil is still in a
liquid state, which could damage the compressor.
The rear expansion valve is a factory calibrated unit and cannot be adjusted or repaired. If faulty or damaged, the expansion valve must be replaced.
