Carrier NEOS 100S, Operation & Service Manual

Page: 57 / 68

6-3 62-11848
6.2.3 Unit Operates Long or Continuously in Cooling
Box
Hot Load Insufficient pull
down time
Defective box insulation or air leak Correct
Refrigeration system
Abnormal pressure 6.2.6
Temperature controller malfunction 6.2.8
Compressor Defective Replace
6.2.4 Unit Will Not Heat or Heating Insufficient
Refrigeration
Abnormal pressure 6.2.6
Temperature controller malfunction 6.2.8
Hot gas solenoid malfunction 5.10
Compressor
Compressor drive (clutch) defective Check
Compressor defective Replace
6.2.5 Defrost Malfunction
Automatic defrost will not
initiate
Defrost thermostat (DTT) open or defective Replace
Hot gas solenoid valve malfunction 5.10
Defrost disabled through cab command 3.6
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 5.10
Condenser Pressure Control valve malfunction 5.10
Frequent defrost
Wet load --
Defrost settings set too low. 3.6
Does not terminate or cycles on
defrost Defrost thermostats (DTT) shorted closed Replace
6.2.6 Abnormal Pressure
Cooling:
High discharge pressure
Condenser coil dirty 5.16
Non-condensables in system 5.7
Refrigerant overcharge 5.6.1
Condenser fan/motor defective Replace motor
Low discharge pressure
Compressor defective Replace
Hot gas solenoid malfunction 5.10
Low refrigerant charge 5.6.1
High suction pressure
Compressor defective Replace
Hot gas solenoid malfunction 5.10
Compressor pressure regulator mis-adjusted (CPR) 5.11
Table 6–2 Mechanical Indications
INDICATION / TROUBLE POSSIBLE CAUSES
REFERENCE
SECTION