jcb JS200 Service Manual page 107

Section B
12 - 12
System Diagnosis (cont'd)
Air in System
Gauge Readings:
Low Side Gauge - High.
High Side Gauge - High.
Other symptoms:
Sight Glass - Bubbles visible during system
operation.
Pipes - Low pressure pipes are hot to the touch.
Diagnosis:
Air is present in the system, possibly from
inadequate evacuation procedure.
Correction:
1. Evacuate A/C system.
2. Check compressor oil for contamination. Check
compressor for proper oil amount. Correct if
necessary.
3. Charge system with R-134a.
4. Operate system and check performance.
Expansion Valve Improperly Mounted or Heat
Sensing Tube Defective (Opening Too Wide)
Gauge Readings:
Low Side Gauge - High.
High Side Gauge - High.
Other symptoms:
Pipes - Large amount of frost or moisture on low side
pipes.
Diagnosis:
Excessive refrigerant in low side pipes possibly
from expansion valve being opened too wide.
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.
9803/6400
Body & Framework
Air Conditioning
LOW SIDE (RED)
LOW SIDE - 2.8 bar (2.8 kgf/cm
HIGH SIDE - 22.1 bar (22.5 kgf/cm
LOW SIDE (RED)
LOW SIDE - 3.5 bar (3.5 kgf/cm
HIGH SIDE - 22.1 bar (22.5 kgf/cm
HIGH SIDE (BLUE)
High
2 )(40 lbf/in
2 )(320 lbf/in
HIGH SIDE (BLUE)
High
2
)(50 lbf/in
2
)(320 lbf/in
Section B
12 - 12
High
2 )
2 )
High
2
)
2
)
Issue 1