Discovery 2. Manual — part 716

AIR CONDITIONING

DESCRIPTION AND OPERATION

82-27

Operation

The rear A/C only operates if the front A/C is on to pump refrigerant through the rear evaporator/blower assembly.
When the rear A/C switch is selected on, the indicator lamp in the switch illuminates and the rear blower relay is
energised. The rear blower relay switches battery power to the blower motor, which runs at the speed selected on the
blower speed switch.

The air from the blower passes through the evaporator matrix, which absorbs heat from the air. The cooled air is then
supplied to the roof vents through the distribution ducts. The heat absorbed by the refrigerant in the evaporator is
sensed by the thermostatic expansion valve. The thermostatic expansion valve then opens and regulates the flow of
refrigerant through the evaporator in proportion to the amount of heat being absorbed from the air.

When the rear A/C switch is selected off, the blower stops. The thermostatic expansion valve senses the subsequent
decrease in temperature of the refrigerant in the evaporator. The thermostatic expansion valve then closes and stops
the flow of refrigerant, except for a minimal bleed flow.

AIR CONDITIONING

82-28

DESCRIPTION AND OPERATION

AIR CONDITIONING

REFRIGERANT RECOVERY, RECYCLING AND RECHARGING

82-29

REFRIGERANT RECOVERY, RECYCLING AND RECHARGING

Refrigerant recovery, recycling and
recharging

$% 82.30.02

Recovery

1. Remove dust caps from high and low pressure

connectors.

2. Connect high and low pressure hoses to

appropriate connections.

3. Open valves on connectors.
4. Turn valves on refrigerant station to correct

positions.

Operate the refrigerant station in accordance
with the manufacturers instructions.

5. Turn Process switch to correct position.
6. Turn Main switch to 'ON'.
7. Allow station to recover refrigerant from

system.

WARNING: Refrigerant must always be
recycled before re-use to ensure that the
purity of the refrigerant is high enough for
safe use in the air conditioning system.

Recycling should always be carried out with
equipment which is design certified by
Underwriter Laboratory Inc. for compliance
with SAE J1991. Other equipment may not
recycle refrigerant to the required level of
purity.

A R134a Refrigerant Recovery Recycling
Recharging Station must not be used with
any other type of refrigerant.

Refrigerant R134a from domestic and
commercial sources must not be used in
motor vehicle air conditioning systems.

8. Close valves on refrigerant station.
9. Turn Main switch to 'OFF'.

10. Close valves on connectors.
11. Disconnect connectors high and low pressure

hoses from connectors.

12. Fit dust caps to connectors.

13. Open tap at rear of station to drain refrigerant

oil.

14. Measure and record quantity of refrigerant oil

recovered from system.

15. Close tap at rear of station.

Evacuation

WARNING: Servicing must only be carried
out by personnel familiar with both the
vehicle system and the charging and testing
equipment. All operations must be carried
out in a well ventilated area away from open
flame and heat sources.

1. Remove dust caps from high and low pressure

connectors.

2. Connect high and low pressure hoses to

appropriate connections.

3. Open valves on connectors.
4. Turn valves on refrigerant station to correct

positions.

5. Turn Process switch to correct position.
6. Turn Main switch to 'ON'.
7. Allow station to evacuate system.

Recharging

NOTE: When recharging, always make
allowance for refrigerant in the line between the
charging station and the vehicle. This is
calculated at 30 grammes/metre of charging
line. System charge weights are 700

±

25

grammes for front A/C system only and 900

±

25 grammes for combined front and rear A/C
system.

1. Close valves on refrigerant station.
2. Close valve on oil charger.
3. Disconnect yellow hose from refrigerant

station.

4. Remove lid from oil charger.
5. Pour same quantity of refrigerant oil into oil

charger as collected during recovery. If the
following components have been renewed, add
the following additional quantity of lubricating
oil:

l

Condenser = 40 cm

3

l

Evaporator = 40 cm

3

l

Pipe or hose = 5 cm

3

/metre

l

Receiver/dryer = 15 cm

3

.

6. Fit lid to oil charger.
7. Connect yellow hose to refrigerant station.
8. Open valve on oil charger.
9. Move pointer on refrigerant gauge to mark

position of refrigerant charge quantity.

+

CAPACITIES, FLUIDS AND

LUBRICANTS, Capacities.

AIR CONDITIONING

82-30

REFRIGERANT RECOVERY, RECYCLING AND RECHARGING

10. Slowly open correct valve on refrigerant station

and allow vacuum to pull refrigerant into
system.

11. Close valve on refrigerant station when correct

amount of refrigerant has been drawn into air
conditioning system.

12. Turn Main switch to 'OFF'.
13. Close valves on connectors.
14. Disconnect high and low pressure hoses from

connectors.

15. Fit dust caps to connectors.