1997 SUBARU LEGACY service

5. Refrigerant Service Procedure
1. WORK FLOW
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4-7SERVICE PROCEDURE
5. Refrigerant Service Procedure

6. Discharge the System
CAUTION:
The following points should be kept in mind when dis-
charging the system.
Be certain that goggles and gloves are worn.
Connect refrigerant recovery system to manifold
gauge set and remove recycle refrigerant from A/C
system.
NOTE:
Refer to appropriate refrigerant recovery system instruction
manual for operation.
G4M0585
1. CONNECTING THE MANIFOLD GAUGE SET
1) Close the high and low side manifold valves.
G4M0586
2) Turn the A/C system ON and turn the IG switch OFF.
3) Attach the high- and low-pressure manifolds to the high
and low services port on the vehicle.
2. PREPARE FOR DISCHARGING
Connect the center manifold hose to the refrigerant recov-
ery system to recycle refrigerant.
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4-7SERVICE PROCEDURE
6. Discharge the System

G4M0596
7. Evacuating and Charging
The following points should be kept in mind when evacu-
ating and charging with a manifold gauge set.
1) Be certain that goggles and gloves are worn.
2) If bulk refrigerant [13.6 kg (30 lb) canister] is used, be
certain to weigh the charge amount carefully, using the
correct equipment, to avoid overcharging the system.
3) The charging procedure described in this section
begins by chargingliquidrefrigerant into the high- pres-
sure side of the systemwith the engine off.The proce-
dure is completed by charging refrigerantvaporinto the
low-pressure side of the system with the engine running.
CAUTION:
Never open the high-pressure manifold valve when the
engine is running.
G4M0597
1. CONNECT THE GAUGE SET
1) Close the high- and low-pressure manifold valves.
2) Attach the low-pressure manifold hose to the low- pres-
sure service port on the vehicle. Check the low- pressure
gauge. If more than 68.6 kPa (0.70 kg/cm
2, 10 psi) is
indicated, discharge the system prior to charging.
3) Attach the high-pressure manifold hose to the high-
pressure service port on the vehicle.
4) Connect the center hose from the manifold to the
vacuum pump.
5) Turn on the vacuum pump.
6) Slowly open the low-pressure manifold valve.
7) When the low-pressure gauge reaches approximately
66.43 kPa (498.3 mmHg, 19.62 inHg), slowly open the
high-pressure manifold valve.
G4M0598
8) Maintain a minimum vacuum level of 100.56 kPa (754.4
mmHg, 29.70 inHg) for a minimum of 15 minutes on a new
system or 30 minutes for an in-service system.
NOTE:
The gauge will read 4 kPa (25 mmHg, 1 inHg) less for
every 304.8 m (1,000 ft) above sea level.
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4-7SERVICE PROCEDURE
7. Evacuating and Charging

G4M0599
2. PERFORM A VACUUM LEAK TEST
1) After 15 minutes (or more) of evacuation, close the
high-pressure manifold valve.
2) Close the low-pressure manifold valve.
3) Turn off the vacuum pump.
G4M0600
4) Note the low side gauge reading.
5) After 5 minutes, re-check the low-pressure gauge read-
ing.
If the vacuum level has changed more than 4 kPa (25
mmHg, 1 inHg), perform an HFC-134a leak test.
If the vacuum reading is about the same as noted in step
2-4), continue on to step 2-6).
G4M0980
6) Carefully attach the can tap to the refrigerant can by
following the can tap manufacturer’s instructions.
7) Disconnect the center manifold hose from the vacuum
pump and connect the hose to the tap valve.
G4M0981
8) If a 13.6 kg (30 lb) container of refrigerant is used a
weight scale will be needed. This scale is to determine the
amount of refrigerant that is used.
Connect the center hose from the manifold to the valve.
Place the 13.6 kg (30 lb) container on the scale, valve end
down.
G4M0603
3. PURGE THE CENTER HOSE
1) Verify that all three hose connections are tight at the
manifold gauge set.
2) Open the valve on the HFC-134a source.
3)With safety equipment in place (goggles and
gloves), use extreme cautionand loosen the center hose
connection at the manifold and allow the HFC-134a to
escape for no more than two or three seconds, then quickly
retighten the hose fitting at the manifold.
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4-7SERVICE PROCEDURE
7. Evacuating and Charging

G4M0604
4. INITIAL CHARGING THROUGH THE HIGH SIDE
1) Connect a tachometer to the engine.
2)With the engine off, start charging by slowly opening
the high-pressure manifold valve.
NOTE:
The initial charge rate can be increased by immersing the
can in lukewarm [Below 38°C (100°F)] water for a short
time.
G4M0605
5. CHECK THE GAUGE READINGS
When both the high- and low-pressure gauge readings are
about equal, or the HFC-134a source is empty, or the sys-
tem has been filled to specifications, close the high- pres-
sure manifold valve.
6. ADD ADDITIONAL CANS
If the HFC-134a source is exhausted, first close the high-
pressure manifold valve, second, close the can tap valve,
then slowly purge the refrigerant from the service hose by
loosening the fitting at the can tap. Repeat steps 15
through 19 as necessary.
G4M0606
7. COMPLETE CHARGING THROUGH THE LOW SIDE
1) Verify that the high-pressure manifold valve is closed
(should have already been closed).
2) Verify that the low-pressure manifold valve is closed
(should have already been closed).
G4M0607
3) With the A/C switch off and the windows rolled down,
start the engine and run at idle rpm.
4) Set the A/C controls on maximum cool and set the
blower speed on the highest setting.
5) Quickly turn the A/C switch on-off-on-off a few times to
prevent initial compressor damage due to“load shock.”
Finish this operation with the A/C switch in the ON position.
6) Raise engine rpm to approximately 1,500 rpm.
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4-7SERVICE PROCEDURE
7. Evacuating and Charging

G4M0608
8. CHARGE THE SYSTEM
1) With the refrigerant source connected and the service
hose purged, slowly open the low-pressure manifold valve,
while checking the low-pressure gauge reading.
CAUTION:
The refrigerant source must be positioned for vapor
(valve up).
2) Keep the low side pressure below 276 kPa (2.81
kg/cm
2, 40 psi) by using the low-pressure manifold valve to
regulate the flow of refrigerant into the system.
3) When the system is fully charged, close the low- pres-
sure manifold valve.
4) Close the valve at the refrigerant source.
Refrigerant capacity
Unit: kg (lb)
Refrigerant Minimum Maximum
HFC-134a 0.55 (1.21) 0.65 (1.43)
9. COMPLETE ALL SYSTEM CHECKS
1) Evaluate the system performance (refer to performance
testing section).
2) Perform leak detection test.
CAUTION:
Always perform leak checking in an environment free
of refrigerant pollution.
Do not disconnect the high- or low-pressure hoses
from the vehicle before leak checking.
10. DISCONNECT THE MANIFOLD GAUGE SET
Remove the high- or low-pressure hoses from the service
ports and install the service port caps.
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4-7SERVICE PROCEDURE
7. Evacuating and Charging

8. Leak Testing
The following points should be kept in mind when conduct-
ing a refrigerant leak test.
1) The A/C system to be tested must have an adequate
refrigerant charge to begin with.
2) The area where the leak test is conducted must be free
of wind and drafts, with still air being the ideal condition.
3) The atmosphere where the leak test is conducted must
be free of refrigerant contamination.
4) Operate the A/C system for approx. 10 minutes, then
turn the engine off an begin the leak test.
5) Refrigerant gas is heavier than air, therefore always
hold the probe below the connection being tested.
6) When checking for a leak along a length of hose or
tube, the leak detector probe must be moved slowly,
approx. 25 mm (1 in) per second making sure probe does
not come in contact with the component being tested.
7) When checking for a leak at a certain point, the leak
detector probe must be held at that point for at least 5
seconds.
G4M0609
1. CHECK THE SYSTEM PRESSURE
With gauges connected to the A/C system, operate the A/C
and confirm that the high side pressure is above 690 kPa
(7.03 kg/cm
2, 100 psi). If not, evacuate and charge the
system before leak checking (refer to evacuation and
charging sections).
2. CLEAN CONNECTIONS BEFORE TESTING
Before testing, use a clean shop towel to wipe off refriger-
ant oil, dirt, or foreign material from all of the connections
and components to be tested.
NOTE:
Since refrigerant oil absorbs refrigerant, excess oil on or
near a connection may falsely signal a leak.
B4M0089
3. CALIBRATE LEAK DETECTOR
Refer to the manufacturer’s instructions for the particular
type of detector used and calibrate the instrument.
CAUTION:
Always make sure that the probe tip filter is clean and
free of contamination.
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4-7SERVICE PROCEDURE
8. Leak Testing

G4M0612
4. LEAK TEST — HIGH-PRESSURE SIDE
Operate the A/C system for approx. 10 minutes, then turn
the engine off and begin the leak test.
1) Begin at the connection of the high-pressure tube to the
evaporator, and work your way along the high- pressure
side of the system to the compressor. There are three
places to check on each tube connection.
2) Check the area.
(1) Check the area where the fitting joins the tube.
G4M0613
(2) Check the area where the two parts of the fitting
join each other.
G4M0614
(3) Check the area where the nut joins the tube.
3) Check the area of the sight glass and pressure switch
(dual switch), and also check the seams of the receiver
drier.
4) Check the connections of the tubes to the condenser,
and also check any welded joints on the condenser.
CAUTION:
An oily area on the fins of the condenser may indicate
a leak.
5) Check the area where the hoses attach to the compres-
sor.
6) Check around the machined portions of the compressor
(where the compressor sections join each other).
7) If equipped, check the thermal limiter on the compres-
sor housing.
8) Check the compressor shaft seal by probing near the
center of the compressor clutch pulley.
NOTE:
Some shaft seals have a very slight amount of normal
leakage [approximately 28 g (1.0 oz) per year].
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4-7SERVICE PROCEDURE
8. Leak Testing