Thermo King 098203, Maintenance Manual

Page: 244 / 264

Diagnosis: Troubleshooting, Warnings and Alarm Codes
242
53 High Pressure Switch Off Error
• Occurs during pretrip (PTI) test only.
• Compressor does not stop during high pressure
cutout switch test.
• Indicates:
• Faulty compressor contactor or control circuit.
• Low refrigerant charge.
• Defective high pressure cutout switch.
• Strong winds causing cooling of condenser coil in
low ambient conditions.
• Check discharge and suction pressure gauge
readings and check refrigerant charge.
• 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).
54 High Pressure Switch On Error
• 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.
• Defective vapor injection.
• Operate unit on Cool and check discharge and
suction pressure gauge readings.
• Enter Manual Function Test menu and test
(operate) Vapor Injection Valve to determine if
valve opens (energizes).
• Check compressor discharge sensor
resistance. Resistance must be approx.
86,000 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.
Alarm Codes, Descriptions and Corrective Actions (Continued)
Code Description Corrective Action