Thermo King RD-MT - Expansion valve open too much; Expansion valve closed too much; Expansion valve needle eroded or leaking; Expansion valve partially closed by ice, dirt or wax

Refrigeration Diagnosis
144
•• Expansion valve open too much
••Expansion valve closed too much
•• Expansion valve needle eroded or leaking
•• •Expansion valve partially closed by ice, dirt or wax
•••Liquid refrigerant entering compressor
•• Restricted line on the low side
••• •Restricted line on the high side
••• •Restricted drier
• Evaporator fan stays running
•• •Evaporator fan not running
• Discharge service valve back seated
• Suction service valve back seated
•• • • • ••Faulty CIS
•• • ••Faulty HGS
••Loose or broken electrical connections
•••• •Thermostat faulty
•••• Compound pressure gauge out of calibration
• Leaky receiver tank outlet valve
•• • ••Leaky check valve
•• ••Faulty check valve
• Leaky receiver tank pressure solenoid (RTPS)
••Closed receiver tank pressure solenoid (RTPS)
Rapid cycling between Cool and Heat Unit cools in Heat and Defrost cycle Unit heats in refrigeration cycle High head pressure Low head pressure No head pressure High suction pressure Low suction pressure No suction pressure Unit operating in a vacuum Receiver sight glass empty Suction line frosting back Unable to pump down system Unable to pull vacuum in low side Unable to hold vacuum in low side Noisy compressor Unit not refrigerating Unit not heating or defrosting
Symptom
Possible Causes