Thermo King 920000, Manual

Page: 143 / 190

143
Refrigeration Diagnosis
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Sy
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Possible Causes
• • • • Overcharge of refrigerant
• • • • • • Shortage of refrigerant
• • • • • No refrigerant
• Air through condenser too hot (ambient)
• Air flow through condenser restricted
• • • Air through condenser too cold (ambient)
• • • Air in refrigerant system
• Condenser fan blades bent or broken
• Air short cycling around evaporator coil
• Air through evaporator restricted
• • • • Evaporator needs defrosting
• • Compressor discharge valves leaking
• • Compressor suction valves leaking
• Too much compressor oil in system
• Faulty oil pump in compressor
• Faulty compressor drive coupling
• Compressor bearing loose or burned out
• • • • • Broken valve plate in compressor
• • Expansion valve power element lost its charge
• • Expansion valve feeler bulb improperly mounted
• • • Expansion valve feeler bulb making poor contact