AC–75 AIR CONDITIONING SYSTEM – TROUBLESHOOTING 8. EXPANSION VALVE IMPROPERLY MOUNTED/HEAT SENSING TUBE DEFECTIVE (OPENS TOO WIDE) Condition: Insufficient cooling N04152 Symptom seen in refrigeration system | Probable cause | Diagnosis | Remedy • Pressure too high on both low and high pressure sides • Frost or large amount of dew on piping on low pressure side | • Trouble in expansion valve or heat sensing tube not installed correctly | • Excessive refrigerant in low pressure piping ↓ • Expansion valve opened too wide | (1) Check heat sensing tube installed condition (2) if (1) is normal, check expansion valve Replace if defective 9. DEFECTIVE COMPRESSION COMPRESSOR Condition: Does not cool N04146 Symptom seen in refrigeration system | Probable cause | Diagnosis | Remedy • Pressure too high on low pressure sides • Pressure too low on high pressure side | • Internal leak in compressor | • Compression defective ↓ • Valve leaking or broken, sliding parts | • Repair or replace compressor