jcb 3CX - Compressor Malfunction; Some Moisture in the System

10 - 7
Air Conditioning
- System Diagnosis (cont'd)
Compressor Malfunction
Gauge Readings:
Low Side Gauge - High.
High Side Gauge - Low.
Diagnosis:
Internal compressor leak or compressor
mechanically broken.
Correction:
1. Evacuate A/C system.
2. Repair or replace compressor.
3. Charge system with R-134a.
4. Operate system and check performance.
Some Moisture in the System
Gauge Readings:
Low Side Gauge - Normal, then sometimes drops to
below zero.
High Side Gauge - Normal, then sometimes goes
high.
Diagnosis:
Moisture in system freezes, temporarily stopping
cycle, normal system operation returns when ice
melts.
Correction:
1. Evacuate A/C system.
2. Replace receiver-drier.
3. Remove moisture by repeatedly evacuating
system.
4. Charge system with R-134a.
5. Operate system and check performance.
LOW SIDE (Blue) HIGH SIDE (Red)
High Low
Section B Body & Framework
9803/3280
Section B
10 - 7
Issue 1
Fault Finding
LOW SIDE - 4.9 bar (5.0 kgf/cm
2
)(71 lbf/in
2
)
HIGH SIDE - 8.3 bar (8.5 kgf/cm
2
)(121 lbf/in
2
)
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
A268090
LOW SIDE (Blue) HIGH SIDE (Red)
Normal to low Normal to high
LOW SIDE - -2.1 bar (-2.1 kgf/cm
2
)(-30 lbf/in
2
)
HIGH SIDE - 14.8 bar (15.0 kgf/cm
2
)(214 lbf/in
2
)
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
A268020
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