jcb JS200 Service Manual page 106

Section B
12 - 11
System Diagnosis (cont'd)
No Refrigerant Circulation
Gauge Readings:
Low Side Gauge - Zero to negative.
High Side Gauge - Low.
Other symptoms:
Receiver-Drier - Frost or moisture on tubes before
and after receiver-drier.
Diagnosis:
Refrigerant flow obstructed by dirt, moisture or
gas leakage from expansion valve heat sensing
tube.
Correction:
1. Evacuate A/C system.
2. Check heat sensing tube at expansion valve.
Replace expansion valve if necessary.
3. Remove expansion valve and attempt removal of
dirt. If dirt cannot be removed, replace expansion
valve.
4. Replace receiver-drier.
5. Charge system with R-134a.
6. Operate system and check performance.
Insufficient Cooling of Condenser or Refrigerant
Overcharge
Gauge Readings:
Low Side Gauge - High.
High Side Gauge - High.
Other symptoms:
Sight Glass - No bubbles visible even at lower engine
RPM.
Diagnosis:
Refrigerant overcharge, condenser cooling fins
clogged with dirt or cooling fans malfunctioning.
Correction:
1. Clean condenser cooling fins.
2. Check cooling fan operation.
3. Evacuate A/C system.
4. Charge system with R-134a.
5. Operate system and check performance.
9803/6400
Body & Framework
Air Conditioning
LOW SIDE (RED)
Zero to negative
LOW SIDE - -1.0 bar (-1.1 kgf/cm
HIGH SIDE - 5.4 bar (5.5 kgf/cm
LOW SIDE (RED)
LOW SIDE - 3.0 bar (3.0 kgf/cm
HIGH SIDE - 22.1 bar (22.5 kgf/cm
HIGH SIDE (BLUE)
2 )(-15 lbf/in
2 )(78 lbf/in
HIGH SIDE (BLUE)
High
2
)(43 lbf/in
2
)(320 lbf/in
Section B
12 - 11
Low
2 )
2 )
High
2
)
2
)
Issue 1