6-3
62-10848
Table 6–2 Mechanical Indications
Indication/Trouble
Possible Causes
Reference
Section
6.2
Refrigeration
6.2.1
Unit Will Not Cool
Compressor malfunction
Compressor drive (clutch) defective
Replace
Compressor defective
Refrigeration system
Defrost cycle has not terminated
Abnormal pressure
Hot gas solenoid malfunction (HGS1)
6.2.2
Unit Runs but has Insufficient Cooling
Compressor
Compressor defective
Refrigeration System
Abnormal pressure
Expansion valve malfunction
Non-existent or restricted evaporator airflow
6.2.3
Unit Operates Long or Continuously in Cooling
Refrigerated compartment
Hot Load
Insufficient pull
down time
Defective refrigerated compartment insulation or air
leak
Correct
Refrigeration system
Abnormal pressure
Temperature microprocessor malfunction
Compressor
Defective
6.2.4
Unit Will Not Heat or Heating Insufficient
Refrigeration
Abnormal pressure
Temperature microprocessor malfunction
Hot gas solenoid malfunction (HGS1)
Compressor
Compressor drive (clutch) defective
Check
Compressor defective
6.2.5
Defrost Malfunction
Automatic defrost will not initiate
Defrost thermostat (DTT) open or defective
Replace
Hot gas solenoid valve malfunction
Defrost disabled through cab command
Manual defrost will not initiate
Microprocessor defective
Replace
Defrost thermostat (DTT) open or defective
Replace
Defrost cycle initiates but does not
defrost
Hot gas solenoid malfunction (HGS1)
Condenser Pressure Control valve malfunction (HGS2)
Frequent defrost
Wet load
--
Defrost settings too low
Does not terminate or cycles on
defrost
Defrost thermostats (DTT) shorted closed
Replace