Subaru XT 1988 Service Manual page 1036

4-7 AIR CONDITIONING SYSTEM
discharge refrigerant from system. Refer to "Discharge
System".
2) When refrigerant has been discharged to a pressure ap-
proaching atmospheric pressure, connect center charging hose
to a vacuum pump.
3) Close both valves of manifold gauge fully. Then start
vacuum pump.
4) Open low-pressure valve and suck old refrigerant from
system.
5) When low-pressure gauge reading has reached to ap-
proximately 66.7 kPa (500 mmHg, 19.69 inHg), slowly open
Repair any leakages found. Refer to "Checking for Leaks"
and "Refrigerant Leaks".
(6) Confirm that both valves of manifold gauge are fully
closed and then change center charging hose from can tap
to vacuum pump.
(7) Open high- and low-pressure valves and operate
vacuum pump to such refrigerant from system. When the
pressure in system has dropped to 94.6 kPa (710 mmHg,
27.95 inHgl, fully close both valves of manifold gauge.
7) The above operation completes evacuation of system.
Next, charge refrigerant. Refer to "Charging Refrigerant".
high-pressure valve.
6) When pressure inside system has dropped to 94.6 kPa
Evacuating system - First step
(710 mmHg, 27.95 inHg). fully close both valves of mani-
fold gauge and stop vacuum pump. Let it stand for 5 to 10
minutes in this state and confirm that the reading does not
rise.
a. The low-pressure gauge reads lower by 3.3 kPa (25 mmHg,
0.98 inHg) per a 300 m (1,000 ft) elevation. Perform evacua-
tion according to the following table.
Elevation
Vacuum of system
m (ft)
kPa (mm Hg, in Hg)
0
(0)
94.6 (710,27.95)
300 (1,000) 91.3 (685,26.97)
600 (2,000)
88.0 (660, 25.98)
900 (3,000) 84.6 (635, 25.00)
NOTE:
Values show readings of the low-pressure gauge.
b. The rate of ascension of the low-pressure gauge should be
less than 3.3 kPa (25 mmHg, 0.98 inHg) in five minutes.
If the pressure rises or the specified negative pressure can
not be obtained, there is a leak in the system. In this case,
immediately charge system with refrigerant and repair the leak
described in the followings.
(1) Confirm that both valves of manifold gauge are fully
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L4-492
Fig. 13
Evacuating system - Second step
L4-493
closed and then disconnect center charging hose from Fig. 14
vacuum pump.
(2) Connect center hose to can tap in place of vacuum
pump. Attach refrigerant can to can tap and pass
refrigerant to manifold gauge.
(3) Loosen the connection of center fitting of manifold
gauge to purge air from center hose.
(4) Open low-pressure valve of manifold gauge and charge
refrigerant into system. After one can [about 0.4 kg (0.9
Ib)] of refrigerant has been charged into system, close
low-pressure valve.
(5) Check for refrigerant leakage with a leak detector.
14
Charging refrigerant
1) Install manifold gauge to system. Refer to "Handling
Manifold Gauge".
a. Be sure to purge air from the high- and low-pressure
charging hoses.
b. If air is mixed with refrigerant gas in system, evacuation
of system should be performed. Refer to "Evacuating
System".
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