LR3/Disco 3
through the floorpan, to the underside of the vehicle, through two drain tubes.
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 for system servicing. Where
auxiliary A/C is installed, connections for the auxiliary refrigerant lines are incorporated near the engine bulkhead.
Under normal operating conditions, the smaller diameter pipes (A/C compressor discharge, liquid refrigerant) are hot to
the touch and the larger diameter pipes (A/C compressor suction, gaseous refrigerant) are cold to the touch.
SYSTEM OPERATION
To accomplish the transfer of heat, the refrigerant is circulated around the system, where it passes through two
pressure/temperature regimes. In each of the pressure/temperature regimes, the refrigerant changes state, during which
process maximum heat absorption or release occurs. The low pressure/temperature regime is from the thermostatic
expansion valve, through the evaporator to the compressor; the refrigerant decreases in pressure and temperature at the
thermostatic expansion valve, then changes state from liquid to vapor in the evaporator, to absorb heat. The high
pressure/temperature regime is from the compressor, through the condenser and receiver drier to the thermostatic
expansion valve; the refrigerant increases in pressure and temperature as it passes through the compressor, then
releases heat and changes state from vapor to liquid in the condenser.
A/C SYSTEM SCHEMATIC
NOTE :
A = Refrigerant liquid; B = Refrigerant vapor; C = Air flow
