Defender (1993+). Manual — part 94

AIR

CONDITIONING

CHARGING AND TESTING EQUIPMENT

Connecting the gauge set

NOTE: 1: There are two methods

of

connecting

the charging and testing equipment, depending
on the operation to be carried out. The method
described for 'evacuating

or

charging with liquid

refrigerant' also applies to 'pressure test' and
'compressor oil level check' operations.

NOTE: 2: Various types of charge and test

equipment are available depending upon the

manufacturer chosen by the user. The equipment
illustrated may differ slightly

in

layout to that

possessed by

t

he

user,

however,

it

is

recommended that

the user adheres to the

appropriate manufacturer's instructions for the

charge and test equipment used in their

8. Put on the safety goggles.

workshop.

Fitting

1.

6.

Place the vehicle in a ventilated area away

from open flames and heat sources. Stop the
engine, open and secure the bonnet.

7.

Check that both service valves are fully open

(turned anti-clockwise).

9.

Remove the caps from the gauge connections

on the service ports.

10.

Coat the threads and flares with refrigerant

oil.

11.

Connect the low pressure charging line (blue)
from valve No.

1

to the compressor suction

service port.

12. Connect the high pressure charging line (red)

from valve No. 2 to the compressor discharge
service port.

13. Using the service wrench, turn the suction

service valve stem 'clockwise' counting the
number of turns necessary to close the valve.

Ensure that all the valves on the charging and

testing equipment are closed. Control valves
on the particular equipment selected are
numbered

1

to 4 as illustrated. The sequence

may vary on other proprietary equipment.

2. Mount a 1 1 , 3 kg drum of refrigerant upside

down on the support at the rear of the
charging equipment, and secure with the
strap.

14. After the valve is fully closed, turn the stem

out (anti-clockwise) half the number of turns
counted, this should position the valve seat in
the mid {test) position.

3.

Connect the hose from the bottom

of

the

'charging cylinder to the refrigerant drum valve.

4.

Connect the hose between the bottom

of

the

charging cylinder and the refrigerant control

valve (No. 4).

5.

Connect the hose between the vacuum pump
valve and the vacuum control valve (No.3).

REISSUED: FEB 1993

11

AIR CONDITIONING

15. Turn the stem on the discharge valve

1.

Place the vehicle in a ventilated area away

clockwise until the pressure rises on the

from open flames and heat sources.

discharge pressure gauge, If the system is to
be evacuated, the discharge service valve

3.

Open and secure the bonnet.

seat must be in the mid (test) position.

4.

Remove the caps from the compressor

connected and ready for proceeding with the

5.

Check that both compressor service valves

required operation.

are fully opened (turned anti-clockwise).

6. Close all valves on the charging and testing

7. Put on safety goggles.

17. If the engine has been operated, it must be

8.

Connect the high pressure charging line (red)

stopped prior to disconnecting the charging

from valve No. 2 to the compressor discharge

and testing equipment.

service port.

18.

Close

both

service

ports

(turn

fully

9.

Run the (blue) hose to an open tapped

anti-clockwise) until fully closed.

container of approximately one litre capacity.

19.

Close all valves

on

the charging and testing

Attach the hose to the container

so

that

it

will

equipment.

not blow out of the container. The purpose of

20. Disconnect the charging lines from the service

the container is to collect any oil carried by

ports.

the refrigerant.

21. Refit the blanking caps to the compressor

10.

Open the compressor discharge service port a

valve stems and service ports, and to the

quarter

of

a turn.

charging lines.

11. Open valve No. 2 fully.

2. Stop the engine.

16. The charging and testing equipment is now

service ports.

Removing

equipment.

22.

Close the bonnet.

12.

Slowly open the valve No. 1 one turn to allow

the refrigerant to escape, if necessary, adjust
the refrigerant flow

so

that the oil captured in

the container is not blown out of the container.

AIR CONDITIONING SYSTEM OPERATIONS

Depressurising

NOTE: The air conditioning refrigeration system

contains 'Refrigerant 12' under pressure, and

before any component

is

disconnected or

removed, the system must be discharged

of

all

pressure.
Refrigerant 12 evaporates

so

rapidly at normal

atmospheric pressures and temperatures that it
tends to freeze anything it contacts. Extreme

care must be taken t o prevent any liquid
refrigerant from contacting the

skin and

especially the eyes. Should any liquid refrigerant
get into the eyes, use a few drops of sterile

13. Measure the amount of

oil

discharged from

mineral oil t o wash them out and then wash the

the system

so

that an equal amount of new oil

eyes with

a

weak solution of boric acid. Seek

can be returned to the system during the

medical attention immediately even though the

charging operation. Discard the old

oil.

initial irritation has ceased after first aid

14.

When the gauge pressure is below 50 psi,

treatment. Always wear safety goggles when

slowly open the valve No. 1 to maintain

opening refrigerant connections.

refrigerant flow.

15.

When the pressure has been reduced, and

WARNING: Open connections slowly, keeping the

the system has been completely discharged,

hands

and

face well clear,

so

that no injury

close the valves Nos. 1 and 2 on the charging

occurs if there i s liquid i n the line. If pressure is

and testing equipment.

noticed allow it to bleed off slowly.

16. Close the compressor discharge service port

(turn anti-clockwise).

17.

Disconnect the high pressure charging line
from the compressor service port.

12

REISSUED:

FEB

1993

AIR

CONDITIONING

NOTE:

If it is necessary to disconnect the

1.

Depressurise the air conditioning system as

compressor hoses, the compressor should be

previously described, then connect the gauge

sealed by fully closing the relevant service valve

set as detailed under 'Charging and Testing

(turn fully clockwise). It is essential to ensure

Equipment'.

that both service valves are open before

2. Adjust both service valve seats to the mid

operating the compressor. Similarly any other

(Test) position.

component

of

the refrigeration system should be

3. Open the low and high pressure valves Nos. 1

capped immediately when disconnected.

and 2.

4.

Start the vacuum pump and check that the
vacuum pump valve is open.

5.

Slowly open the vacuum control valve No. 3.

If

the vacuum is applied to the system too

quickly, the residual oil may be drawn out.

18. Open the refrigeration drum valve.
19.

Open the valve at the base of the charging
cylinder and allow approximately 0,25 kg of
refrigerant to enter the cylinder.

20. Close the refrigeration drum valve and the

valve at the base of the charging cylinder.

21. Open the refrigerant control valve (valve

No.

4) and flush out the high and low pressure
lines by opening valves Nos. 1 and 2
momentarily until a white stream of refrigerant
is observed.

6.

In

evacuating the system it is necessary to

lower the pressure

so

that the boiling point of

water in the system is lower than the
surrounding air temperature.

At

an ambient

temperature

of

23.8°C (75°F),

it

is necessary

to lower the system pressure to 29.5 in Hg
vacuum to bring the boiling point of water to

22. Close all valves on the charging and testing

22°C (72°F). Atmospheric pressure (and
vacuum gauge readings) decrease as altitude

23.

The

air

conditioning

system

is

now

increases by approximately 25 mm Hg per
300 m. The following chart provides a guide to
the various gauge readings at differing
altitudes, for the same 10 mm Hg absolute

equipment, and fit the blanking caps.

depressurised.

Evacuating

pressure.

Whenever the system has been opened to the

Altitude, f t

m

Vacuum Reading in Hg mm

atmosphere it is necessary that the system be

0

0

29.5

750

evacuated to remove all air and moisture. It

is

also

1,000

300

28.5

725

an essential preliminary operation to charging the

2,000

600

27.4

695

system with Refrigerant 12. The evacuate operation

3,000

900

26.4

670

also provides a check for leaks due to faulty

4,000

1200

25.4

645

connections.

5,000

1500

24.5

622

6,000

1800

23.5

596

7,000

22.6

574

8,000

2400

21.8

554

9,000

2700

20.9

530

10,000

3000

20.1

510

REISSUED:

FEB

1993

13