AC–74 AIR CONDITIONING SYSTEM – TROUBLESHOOTING 6. REFRIGERANT OVERCHARGE OR INSUFFICIENT COOLING OF CONDENSER Condition: Insufficient Cooling N04151 Symptom seen in refrigeration system | Probable cause | Diagnosis | Remedy • Pressure too high on both low and high pressure sides • No air bubbles seen through the sight of glass even when the engine rpm is lowered. | • Unable to develop sufficient performance due to excessive refrigerant in system • Insufficient cooling of condenser | • Excessive refrigerant in cycle → refrigerant overcharged • Condenser cooling insufficient → condenser fins clogged or fan motor faulty | (1) Clean condenser (2) Check fan motor operation (3) If (1) and (2) are in normal state, check amount of refrigerant Charge proper amount of refrigerant 7. AIR PRESENT IN REFRIGERATION SYSTEM Condition: insufficient cooling NOTE: These gauge indications are shown when the refrigeration system has been opened and the refrigerant charged without vacuum purging. N04153 Symptom seen in refrigeration system | Probable cause | Diagnosis | Remedy • Pressure too high on both low and high pressure sides • The low pressure piping is hot to the touch • Bubbles seen in sight glass | • Air entered in refrigeration system | • Air present in refrigeration system • Insufficient vacuum purging | (1) Check compressor oil to see if dirty or insufficient (2) Evacuate air and charge new refrigerant N09033