10 - 3
Section B
9803/3280
Section B
10 - 3
Issue 1
Fault Finding
A401380
C
B
50
40
30
30
0
10
20
60
70 80
90
100
110
120
350
150
100
500
0
50
200 250
300
350
400
450
A
Air Conditioning - System Diagnosis
This section gives an overview of the following conditions:
Normally Functioning A/C System
Low R-134a Charge
Poor Refrigerant Circulation
No Refrigerant Circulation
Insufficient Cooling of Condenser
Air in System
Expansion Valve Improperly Mounted
Compressor Malfunction
Moisture in the System
Component Key:
A
High Pressure/Temperature Gas.
B
Low Pressure/Temperature Gas.
C
High Pressure Liquid.
LOW SIDE - 2.0 bar (2.0 kgf/cm
2
)(29 lbf/in
2
)
HIGH SIDE - 14.8 bar (15.1 kgf/cm
2
)(215 lbf/in
2
)
Normally Functioning A/C System
Gauge Readings:
Low Side Gauge -
Normal.
High Side Gauge -
Normal.
Other Indications:
Sight Glass -
Clear.
Discharge Air -
Cold.
Note:
Normal gauge readings will depend on system
components and ambient conditions, make sure that the
valves are closed and the readings are stable and that the
system has a full charge.
The pressures on the manifold at 25 °C with the engine at
1500 RPM, the blower on maximum and the thermostat set
to maximum, should be approximately:
Typically, the high pressure is 6 - 8 times the low pressure.
LOW SIDE (Blue)
HIGH SIDE (Red)
Normal
Normal
