Case 580SR Service Manual page 793

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PERFORMANCE TEST EXAMPLE 2
7
6
5
1. High side low
2. High side hand valve closed
3. High side hose connected to high side service
connector
4. Not used
PROBLEM
Insufficient cooling.
CAUSE
Refrigerant excessively low.
CONDITIONS*
Low side pressure very low.
Gauge should read 1-2 bar.
High side pressure too low.
Gauge should read 13.3-14.8 bar.
Evaporator air warm.
Low pressure switch cutting out.
CORRECTIVE PROCEDURES
1. Leak test the system.
2. Discharge and recover the refrigerant from the
system.
3. Repair leaks.
4. Check compressor oil to ensure no loss.
5. Evacuate the system.
6. Charge the system.
7. Performance test the system.
SECTION 50 - CAB HEATING AND AIR CONDITIONING
Performance Test Example 2
4
5. Low side hose connected to low side service
connector
6. Low side hand valve closed
7. Low side normal
DIAGNOSIS
System refrigerant is extremely low. A serious leak
is indicated.
NOTE: * test procedure based upon ambient tem-
perature of 35 °C.
For proper high side gauge reading for other ambi-
ent temperatures, refer to the pressure temperature
chart.
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