Thermo King 098916, Maintenance Manual

Page: 178 / 196

Diagnosis: Troubleshooting, Status Messages, Alarm Codes
177
54 High Pressure Cutout Switch On Error
(Check Alarm)
• Occurs during pretrip (PTI) test only.
• Compressor does not start within normal time
during high pressure cutout switch test.
• Indicates:
• High pressure cutout switch did not respond to
pressure change within 5 seconds
• Air in refrigeration system
• Defective high pressure cutout switch
• Check discharge and suction pressure gauge
readings.
• Enter Manual Function Test menu. Start the
following components together: compressor
100 percent, compressor and evaporator fans
(high). Discharge pressure should increase
and compressor should stop at 2250 kPa, 22.5
bar, 326 psig (high pressure cutout switch
opens). Then start condenser fan. Discharge
pressure must drop quickly (10 to 20 seconds)
to 1550 kPa, 15.5 bar, 225 psig and
compressor should start (switch closes)
56 Compressor Temperature Too High
(Shutdown Alarm)
• Compressor discharge line temperature is above
148 C (298 F). Compressor stopped until discharge
line temperature decreases to normal.
• Indicates:
• Air in refrigeration system
• Low refrigerant charge
• Defective compressor or valve plate
• Defective liquid injection system
• Wrong or defective sensor
• Operate unit on Cool and check discharge and
suction pressure gauge readings.
• Enter Manual Function Test menu and test
(operate) Injection Valve to determine if valve
opens (energizes).
• Check compressor discharge sensor
resistance. Resistance must be 100,000 ohms
at 25 C (77 F).
• Check discharge line temperature with a
separate electronic thermometer and compare
to “HIGH PR TEMP” shown in the Data menu
of controller.
NOTE: Unit will operate normally without
compressor sensor. However, controller
compressor high temperature protection is
not active.
57 AFAM Control Module or Motor Error
(Check Alarm)
• Controller is unable to adjust vent door to desired
position.
• Indicates:
• Frozen or stuck vent door
• Defective linkage
• Defective control module
• Open circuit to control module or motor
• Defective motor
• Visually inspect the vent door and linkage for
ice or obstruction. Check for proper linkage
adjustment.
• Check wiring connections to the AFAM circuit
board for continuity using a high quality
multimeter.
• Check motor winding for continuity using a
high quality multimeter.
Alarm Codes, Descriptions and Corrective Actions (Continued)
Code Description Corrective Action