10 - 4
Air Conditioning
- System Diagnosis (cont'd)
Low R-134a Charge
Gauge Readings:
Low Side Gauge -
Low.
High Side Gauge -
Low.
Other symptoms:
Sight Glass -
Bubbles continuously visible.
Diagnosis:
System slightly low on R- 134a, due to leak or
incorrect charge.
Correction:
1.
Leak test system.
2.
Evacuate A/C system.
3.
Repair system leaks.
4.
Charge system with R-134a.
5.
Operate system and check performance.
Poor Refrigerant Circulation
Gauge Readings:
Low Side Gauge -
Zero to negative.
High Side Gauge -
Low.
Other symptoms:
Receiver-Drier -
Frost on tubes from receiver-drier
to evaporator unit.
Diagnosis:
Refrigerant flow obstructed by dirt, receiver-drier
clogged.
Correction:
1.
Evacuate A/C system.
2.
Replace receiver-drier.
3.
Charge system with R-134a.
4.
Operate system and check performance.
LOW SIDE (Blue)
HIGH SIDE (Red)
Low
Low
Section B
9803/3280
Section B
10 - 4
Issue 1
Fault Finding
LOW SIDE (Blue)
HIGH SIDE (Red)
Zero to negative
Low
LOW SIDE - 0.76 bar (0.77 kgf/cm
2
)(11 lbf/in
2
)
HIGH SIDE - 8.3 bar (8.5 kgf/cm
2
)(121 lbf/in
2
)
LOW SIDE - -1.0 bar (-1.1 kgf/cm
2
)(-15 lbf/in
2
)
HIGH SIDE - 5.4 bar (5.5 kgf/cm
2
)(78 lbf/in
2
)
50
40
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30
0
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90
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350
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0
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450
A268030
50
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30
0
10
20
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90
100
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120
350
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500
0
50
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450
A268040