62-61753-21     
24  COMPRESSION RATIO EXCEEDED 
  TRIGGER ON: If the compressor compression ratio is greater than 21 for 20 seconds. 
  UNIT CONTROL:   Engine operation: Engine and unit shutdown and alarm.  
      Standby operation: Refrigeration system shutdown and alarm with PSCON 
      still energized. 
  RESET CONDITION: Auto reset when compression ratio is less than 21 for 3 minutes or, 
alarm may be manually reset via keypad or by turning the unit off, then back on again. 
NOTE: Follow the steps below until a problem is found. Once a repair or correction has been made, the active 
alarm should clear itself (refer to reset condition above). Operate the unit through the appropriate modes to see if 
any active alarm occurs. Continue with the steps below as necessary. 
Look for high discharge or low suc-
tion pressure causes. 
Discharge and suction pressures must be in normal 
range for the current ambient and refrigerated com-
partment temperature conditions. Refer to Abnormal 
Pressure Trouble Shooting Section 9.4.7.