7−38
62-11389
Alarm
NO.
Steps Alarm/Cause Corrective Action
53 BOX TEMP OUT-OF-RANGE - Continued
NOTE: Follow the steps below until a problem is found. Once a repair or correction has been made, clear the
alarm(s). (See Note 1 page 7−2.) Operate the unit through the appropriate modes to see if any active alarm
occurs. Continue with the steps below as necessary.
1 Check Compartment Doors
Inspect all trailer compartment doors. Must be closed, no air leakage.
2 Defrost Evaporator
Initiate Manual Defrost Cycle. Must terminate automatically.
All ice cleared from evaporator coil.
3 Check For Any Shutdown Alarm(s)
Check the Alarm List for any
Shutdown Alarms.
Alarm conditions must be corrected and the alarm
cleared to continue.
4 Check For Low Refrigerant Pressure Alarm
Check for alarm 18. Alarm conditions must be corrected and the alarm
cleared to continue.
5 Check Refrigerant Level
Visually check refrigerant level in
receiver.
Must be at correct level. Refer to Section 8.6.2.
6 Check System Pressures
Install manifold gauge set and check
system pressures.
Suction & Discharge Pressures must be in the nor-
mal range. Suction & Discharge Pressures must
have the same reading on gauges & on micro dis-
play.
7 Check Evaporator Motor or Contactor Alarm
Check for alarm 77 or 109. Must be corrected and cleared to continue.
8 Verify accuracy of RAT & SAT sensors
Verify accuracy of RAT & SAT using
infrared or other accurate temperat-
ure testing tool.
RAT & SAT readings must be within $3°F (1.7°C) of
test temperature tool reading.
9 Perform Pretrip Check
Clear Active Alarm list, then run
Pretrip & check for any new alarms.
Any active alarms must be corrected and cleared
before proceeding.
10 Check For Low Delta-T
Read Delta-T from Unit Data. In Cool, the Delta-T must be greater than(cooling
more than) -1°F (-0.56°C.)
In Heat the Delta-T must be greater than 0 (SAT
must be higher than RAT.)
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