Air Inlet Housing

AIR CONDITIONING

82-10

DESCRIPTION AND OPERATION

Thermostatic Expansion Valve
The thermostatic expansion valve meters the flow of refrigerant into the evaporator, to match the refrigerant flow with 
the heat load of the air passing through the evaporator matrix.

The temperature and pressure of the refrigerant leaving the evaporator act on the thermostatic expansion valve to 
control the volume of refrigerant flowing through the evaporator. The warmer the air flowing through the evaporator 
matrix, the more heat available to evaporate refrigerant and thus the greater the volume of refrigerant allowed through 
the metering valve.

Evaporator
The evaporator is installed in the heater assembly between the blower and the heater matrix, to absorb heat from the 
exterior or recirculated air. Low pressure, low temperature refrigerant changes from liquid to vapour in the evaporator, 
absorbing large quantities of heat as it changes state.

Most of the moisture in the air passing through the evaporator condenses into water, which drains through the floorpan 
to the underside of the vehicle through two drain tubes.

Evaporator and Thermostatic Expansion Valve

1 Insulated connecting pipes
2 Thermostatic expansion valve

3 Evaporator

Refrigerant Lines
To maintain similar flow velocities around the system, the diameter of the refrigerant lines varies to suit the two 
pressure/temperature regimes. The larger diameters are installed in the low pressure/temperature regime and the 
smaller diameters are installed in the high pressure/temperature regime.

Low and high pressure charging connections are incorporated into the refrigerant lines near the front RH corner of the 
engine compartment.

Air Inlet Housing
The air inlet housing directs fresh air into the heater unit. The air inlet housing is centrally mounted on the engine 
bulkhead, below a ventilation grille in the bonnet, and secured to the bulkhead closing panels.

A serviceable particle filter, or particle/odour filter, is installed in the air inlet housing to prevent odours and/or 
particulate matter from entering the vehicle with the fresh air.