Subaru XT 1988 Service Manual page 1066

4-7 AIR CONDITIONING SYSTEM
Performance Test Diagnoses
Of various conditions caused to the air conditioning system,
the characteristics revealed on manifold gauge reading are
shown in the following.
Condition
I
INSUFFICIENT REFRIGERANT CHARGE
I
Low·pressure
gauge
Fig. 90 A26-069
I
ALMOST NO REFRIGERANT
I
Low-pressure
gauge
Fig. 91
A26-070
FAULTY EXPANSION VALVE
Insufficient cooling.
Bubbles appear in sight
glass.
No cooling action.
In sight glass appear a lot
of bubbles or something
like mist.
Slight cooling.
As to the method of a performance test, refer to the item of
"Performance Test".
Each shaded area on the following tables indicates a reading of
the normal system when the temperature of outside air is
32.5°C (91°F).
Probable cause
Refrigerant is small, or
leaki ng a little.
Serious refrigerant leak.
Corrective action
1. Lea k test.
2. Repair leak.
3.
Charge system.
Evacuate, as necessary, and
recharge system.
Stop compressor immedi-
ately.
1. Leak test.
2. Discharge system.
3.
Repair leak(s).
4. Replace receiver drier if
necessary.
5. Check oi.! level.
6.
Evacuate and recharge
system.
Low-pressure
gauge Sweating or frosted expan-
sion valve inlet.
Expansion valve restricts
refrigerant flow.
• Expansion valve is clog-
ged.
If valve inlet reveals sweat
or frost:
1.
Discharge system.
2. Remove valve and clean
it. Replace it if neces-
sary.
A26-Q71
Fig. 92
44
• Expansion valve is in-
operative.
Valve stuck closed.
Thermal bulb has
lost charge.
3. Evacuate system.
4. Charge system.
If valve does not operate:
1. Discharge system.
2. Replace valve.
3. Evacuate and charge
system.