Range Rover P38
82
AIR CONDITIONING
NEW RANGE ROVER
14
DESCRIPTION AND OPERATION
Evaporator temperature sensor
The evaporator temperature sensor provides the ATC
ECU with an input of the evaporator air outlet
temperature. The sensor is installed in the RH side of
the heater unit casing and protrudes into the airflow
leaving the the evaporator. The ATC ECU uses the
input to prevent the formation of ice on the evaporator.
Heater coolant temperature sensor
The heater coolant temperature sensor provides the
ATC ECU with an input related to the temperature of
the coolant entering the heater matrix. The sensor is
attached to the outside of the coolant inlet pipe, next
to the heater matrix.
Sunlight sensor
The sunlight sensor is installed in the centre of the
windscreen demist vents in the fascia and provides
the ATC ECU with an input of light intensity. The ATC
ECU uses the input to measure the solar heating load
on the vehicle.
Dual pressure switch
The dual pressure switch protects the refrigerant
system from extremes of pressure and controls the
operating speed of the condenser fans. The dual
pressure switch is installed in the top of the receiver/
drier and senses receiver/ drier outlet pressure.
If the minimum or maximum refrigerant pressure limit
is exceeded, switch contacts open to disconnect the
power supply line between the ATC ECU and the
compressor clutch. The minimum pressure limit
protects the compressor, by preventing operation of
the system unless there is a minimum refrigerant
pressure (and thus refrigerant and lubricating oil) in
the system. The maximum pressure limit keeps the
refrigerant system within a safe operating pressure.
A separate set of switch contacts control the operating
speed of the condenser fans. Depending on the
refrigerant pressure, the switch contacts:
•
Close to energise the condenser fan relays
and run the condenser fans in parallel (fast
speed).
•
Open to de-energise the condenser fan
relays and run the condenser fans in series
(slow speed).
Single pressure switch
The single pressure switch controls the on/ off
switching of the condenser fans while the air
conditioning is on. The single pressure switch is
installed in the refrigerant line between the condenser
and the receiver/ drier. Depending on the refrigerant
pressure, the switch contacts:
•
Close to energise the condenser fan
control relay and run the condenser fans.
•
Open to de-energise the condenser fan
control relay and stop the condenser fans.
Distribution ducts
The distribution ducts are the same as those on non
A/C vehicles except for two additional ducts which
supply air to rear passenger face vents. The additional
ducts are installed in the centre console, and connect
the ducts supplying the outboard face level vents in
the fascia to a dual vent assembly at the rear of the
centre console cubby box.
