New Holland CX720 Repair Manual page 3053

BODY AND STRUCTURE - ENVIRONMENT CONTROL Air-conditioning system
GAUGE READINGS AND INTERPRETATIONS
EXAMPLE 8
Problem:
Insufficient or no cooling.
Cause:
Improper operation of thermostatic expansion valve (stuck open)
CONDITIONS*
1. Low side pressure too high.
2. High side pressure too high.
3. Evaporator air warm.
4. Evaporator and suction hose (to compressor) surfaces show considerable moisture.
CORRECTIVE PROCEDURES
1. Check for sticking expansion valve:
2. Operate the system at maximum cooling
3. Check the low side gauge. The pressure should drop slowly.
4. If the test indicates that the expansion valve is defective, proceed as follows:
5. Recover the refrigerant from the system.
6. Replace the expansion valve.
7. Evacuate the system.
8. Charge the system.
9. Performance test the system.
DIAGNOSIS: Thermostatic expansion valve is allowing too much refrigerant to flow through the evaporator coils.
Valve may be stuck open.
NOTE: * For proper high/low side gauge reading, refer to the Air Conditioning Temperature/Pressure Chart.
2 4/7/2006
E.40.C / 25