AC–72 AIR CONDITIONING SYSTEM – TROUBLESHOOTING 2. MOISTURE PRESENT IN REFRIGERATION SYSTEM Condition: Periodically cools and then fails to cool N04145 Symptom seen in refrigeration system | Probable cause | Diagnosis | Remedy • During operation, pressure on low pressure side sometimes becomes a vacuum and sometimes normal • Moisture entered in refrigeration system freezes at expansion valve orifice and temporarily stops cycle, but normal state is restored after a time when the ice melts • Drier in oversaturated state ↓ • Moisture in refrigeration system freezes at expansion valve orifice and blocks circulation of refrigerant (1) Replace receiver/drier (2) Remove moisture in cycle through repeatedly evacuating air (3) Charge new refrigerant to proper amount 3. INSUFFICIENT REFRIGERANT Condition: insufficient cooling N04148 Symptom seen in refrigeration system | Probable cause | Diagnosis | Remedy • Pressure low on both low and high pressure sides • Bubbles seen in sight glass continuously • insufficient cooling performance • Gas leakage at some place in refrigeration system • Insufficient refrigerant in system • Refrigerant leaking (1) Check for gas leakage with leak detector and repair if necessary (2) Charge refrigerant to proper amount (3) If pressure indicated value is near 0 when connected to gauge, create the vacuum after inspecting and repairing the location of the leak