6-2
Diagnosis Procedures
Refrigeration Maintenance and Service Operations
CSR-20 & CSR-40, September 1999
Specific Refrigeration System Problems
-52 Modulation System Failure (Check or Shutdown
Alarm)
-63 Bypass (Warm Gas) Valve Circuit Failure (Check
Alarm)
-69 Dehumidify Valve Circuit Failure (Check Alarm)
-82 Compressor Over Temperature (Check Alarm):
Indicates probably liquid injection system failure.
Low Refrigerant Charge
-55 High Speed Evaporator Fan Failure (Check or
Shutdown Alarm)
-56 Low Speed Evaporator Fan Failure (Check or
Shutdown Alarm)
-64 Pretrip Preconditioning Failure (Check Alarm)
-82 Compressor Over Temperature (Check Alarm)
Obstruction in the Low or High Side
-50 Compressor Current Out-of-Range (Check or
Shutdown Alarm)
-51 Unit Current Out-of-Range in COOL Mode (Check or
Shutdown Alarm)
-55 High Speed Evaporator Fan Failure (Check or
Shutdown Alarm)
-56 Low Speed Evaporator Fan Failure (Check or
Shutdown Alarm)
-64 Pretrip Preconditioning Failure (Check Alarm)
-82 Compressor Over Temperature (Check Alarm)
-85 Compressor Current Out-of-Range (Check or
Shutdown Alarm)
High Refrigerant Charge
-50 Compressor Current Out-of-Range (Check or
Shutdown Alarm)
-51 Unit Current Out-of-Range in COOL Mode (Check or
Shutdown Alarm)
-85 Compressor Current Out-of-Range (Check or
Shutdown Alarm)
Hermetic Refrigeration System Visual Inspection and
Diagnosis
First correct all mechanical or electrical system problems.
Then if the alarms codes recorded during a Full Pretrip Test do
not readily identify a specific refrigeration system problem,
perform a visual inspection of the container and each refrigera-
tion system component. Refer to the Hermetic Refrigeration
System Visual Inspection and Diagnosis Chart on page 6-3.
8.
After the last alarm code (ALM 1) has been viewed and
recorded, the left display flashes “ENTER” (the code
number of the last alarm still appears in the right display).
NOTE: Clear the Alarm codes ONLY after the
alarm codes are documented and problems
repaired. Clearing the codes erases them from
the controller Alarm display memory.
NOTE: If the ENTER key is not pressed within 10
seconds, the controller will default (return) to the
Standard Display.
9.
To clear all alarm codes from the current display memory,
press the ENTER key while “ENTER” flashes in the left
display. The display briefly shows “ALARM CLEAR”.
WARNING: Some unit malfunctions will cause an
Alarm and unit shutdown condition. When the
alarm codes are cleared, the unit will start auto-
matically.
10. The controller then returns to the Standard Display.
Use Alarm Codes to Identify and Diagnose Potential
Problems
See “Alarm Codes, Descriptions and Corrective Actions” in
Chapter 4 of this manual to view a list of problems that may
cause the controller to record a specific alarm code.
Identify, diagnose and correct any mechanical and electri-
cal system problems listed in the “Corrective Action” column
first. If no mechanical or electrical system problems can be
located; or if all mechanical or electrical system problems have
been corrected but the unit still fails to pass a Full Pretrip Test,
identify and diagnose potential refrigeration system problems.
Several alarm codes identify specific refrigeration system
problems. To simply diagnosis, general refrigeration system
problems have been grouped into three areas: Low refrigerant
charge, obstruction in the low or high side and high refrigerant
charge. Each alarm code that can be generated by the system
problem is then listed and briefly described. Also:
• When only one of the alarm codes listed below is record-
ed during a Full Pretrip Test, a mechanical or electrical
system cause is highly probable.
• When two are more of the alarm codes listed below are
recorded, the likelihood of a problem inside the refriger-
ation system greatly increases.
