1 | Alarm Code | Cause | Components | Troubleshooting | Corrective Actions |
2 | AL05 Manual Defrost Switch Failure | Controller has detected continuous Manual Defrost Switch activity for five minutes or more. | Keypad | Power cycle the unit. | Resetting the unit may correct problem, monitor the unit. If the alarm reappears after 5 minutes replace the keypad. |
3 | AL06 Keypad or Keypad Harness Fail | Controller has detected one of the keypad keys is continuously activity. | Keypad or Harness | Power cycle the unit. | Resetting the unit may correct problem, monitor the unit. If the alarm reappears replace the keypad and harness. |
4 | AL07 Fresh Air Vent Open with Frozen Set Point | The VPS is reading greater than 0 CMH while unit is in frozen mode. | Vent Position Sensor (VPS) | Manually reposition vent and confirm using Cd45. Refer to VENT POSITION SENSOR SERVICE Section 6.25. | If unable to obtain zero reading, replace defective VPS. |
5 | AL10 CO2 Sensor Failure | Alarm 10 is triggered when the CO2 sensor voltage is operating outside of the 0.9 v to 4.7 v range, or if the sensor is out of range. | This is a display alarm and has no associated failure action. | Refer to eAutoFresh manual. | The alarm is triggered off when voltage is within operating range. |
6 | AL11 Evaporator fan 1 IP | Alarm 11 is triggered when configured for single evap operation and MC6 sensed high. | Evaporator Fan 1 | The unit will suspend probe check diagnostic lo- gic and disable the probe check portion of defrost cycle. | AL11 is triggered off when MC6 sensed low. |
7 | AL12 Evaporator fan 2 IP | Alarm 12 is triggered when configured for single evap operation and KB10 sensed high. | Evaporator Fan 2 | The unit will suspend probe check diagnostic lo- gic and disable the probe check portion of defrost cycle. | AL11 is triggered off when KB10 sensed low. |
8 | AL15 Loss of cooling | Unit fails to achieve 0.25C temperature delta for eight minutes before a probe−check defrost and then fails again for thirty minutes after the probe−check. | N/A | Power cycle the unit. | Resetting the unit may correct problem, monitor the unit. |
9 | AL20 Control Contactor Fuse (F3) | Control power fuse (F3A or F3B) is open. | Check F3A, if the fuse is open: | Check PA, PB, CH coils for short to ground, if short is found: | Replace the defective coil. Replace the fuse. |
10 | Check F3B, if the fuse is open: | Check ESV coil resistance at TP7 to TP9, if short to ground, or if resistance is less than 4 ohms, coil is defective. Check CF, ES, EF, HR coils for short to ground, if short is found, coil is defective. | Replace the defective coil. Replace the fuse. | | |
11 | Check Voltage at QC1: | If voltage is present, it indicates a defective microprocessor. | Refer to Controller Service Section 6.23. | | |
12 | AL21 Control Circuit Fuse (F1/F2) | One of the 18 VAC controller fuses (F1/F2) is open. Refer to Cd08. | System Sensors | Check system sensors for short to ground. | Replace defective sensor(s) |
13 | Wiring | Check wiring for short to ground. | Repair as needed. | | |
14 | Controller | Controller may have an internal short. | Replace controller, refer to Controller Service Section 6.23. | | |
15 | AL22 Evaporator IP | Evaporator motor internal protector (IP) is open. | Evaporator Motor | Shut down unit, disconnect power, & check Evaporator Motor IP at plug connection pins 4 & 6. | Replace defective evaporator fan motor, refer to EVAPORATOR FAN MOTOR Service Section 6.16. |
16 | AL23 Loss of Phase B | Controller fails to detect current draw. | Incoming Power | Check incoming power source. | Correct power source as required. |
17 | AL24 Compressor IP | Compressor internal protector (IP) is open. | Compressor | Shut down unit disconnect power, & check resistance of compressor windings at contactor T1−T2, T2−T3. | Monitor unit, if alarm remains active or is repetitive replace the compressor at the next available opportunity, refer to COMPRESSOR Service Section 6.8. |
18 | AL25 Condenser IP | Condenser fan motor internal protector (IP) is open. | Insufficient Air Flow | Shut down unit and check condenser fan for obstruc- tions. | Remove obstructions. |
19 | Condenser Fan Motor | Shut down unit, disconnect power, & check Condenser Fan Motor IP at plug con- nection pins 1 & 2. | Replace defective condenser fan motor, refer to Condenser Fan Motor Assembly Service Section 6.11. | | |
20 | AL26 All Sensors Failure: Supply/Return Probes | Sensors out of range. | All sensors. detected as out of range | Perform Pre−trip P5: | If P5 passes, no further action is required. |
21 | If P5 fails, replace the defective sensor as determined by P5, refer to TEMPERATURE SENSOR Service Section 6.24. | | | | |
22 | AL27 Analog to Digital Accuracy Failure | Controller AD converter faulty. | Controller | Power cycle the unit. If the alarm persists, it indicates a defective microprocessor. | Replace defective microprocessor, refer to Controller Service Section 6.23. |
23 | AL29 AutoFresh Failure | Alarm 29 is triggered if CO2 or O2 level is outside of the limit range and the vent position is at 100% for longer than 90 minutes. | Alarm LED will be activated and user intervention is re- quired. | Refer to eAutoFresh manual. | The alarm is triggered off when atmospheric con- ditions are within limit settings. |
24 | AL50 Air Vent Position Sensor (VPS) | VPS Sensor out of range. | Vent Position Sensor (VPS) | Make sure VPS is secure. | Manually tighten panel. |
25 | If the alarm persists, replace the sensor or the assembly. | Replace VPS. | | | |
26 | AL51 EEPROM Failure | Controller Memory Failure | Controller | Pressing the ENTER key when “CLEAr” is displayed will result in an attempt to clear the alarm. | If action is successful (all alarms are inactive), AL51 will be reset. |
27 | Power cycle the unit. If the alarm persists, it indicates defective controller memory. | Replace defective controller, refer to Controller Service Section 6.23 | | | |
28 | AL52 EEPROM Alarm List Full | Alarm list queue is full. | Active Alarms | Repair any alarms in the queue that are active. Indicated by “AA”. | Clear alarms, refer to CONTROLLER ALARMS Table 3-6. |
29 | AL53 Battery Pack Failure | Battery voltage low | Battery | If this alarm occurs on start up, allow a unit fitted with rechargeable batteries to operate for up to 24 hours to charge rechargeable batteries sufficiently. Once fully charged, the alarm will deactivate. | To clear the alarm press ENTER and ALT simul- taneously at the startup of Cd19 (Battery Check). If alarm persists, replace the battery pack, refer to Section 6.23.5 Battery Replacement. |
30 | AL54 Primary Supply Sensor (STS) | Invalid Supply Temperature Sensor (STS) reading. | Supply Temperature Sensor (STS) | Perform Pre−trip P5: | If P5 passes, no further action is required. |
31 | If P5 fails, replace the defective sensor as determined by P5, refer to TEMPERATURE SENSOR Service Section 6.24. | | | | |
32 | AL56 Primary Return Sensor (RTS) | Invalid Return Temperature Sensor (RTS) reading. | Return Temperature Sensor (RTS) | Perform Pre−trip P5: | If P5 passes, no further action is required. |
33 | If P5 fails, replace the defective sensor as determined by P5, refer to TEMPERATURE SENSOR Service Section 6.24. | | | | |
34 | AL57 Ambient Sensor (AMBS) | Invalid Ambient Temperature Sensor (AMBS) reading. | Ambient Temperature Sensor (AMBS) | Test the AMBS, refer to TEMPERATURE SENSOR Service Section 6.24. | Replace AMBS if defective, refer to TEMPERATURE SENSOR Service Section 6.24. |
35 | AL58 Compressor High Pressure Safety (HPS) | High pressure safety switch remains open for at least one minute. | High Pressure Switch (HPS) | Test the HPS; refer to High Pressure Switch, Section 6.9. | Replace HPS if defective, refer to High Pressure Switch, Section 6.9. |
36 | Refrigeration System | Check unit for air flow restrictions. | Clean or remove any debris from coils. | | |
37 | AL59 Heater Termination Thermostat (HTT) | Heat Termination Thermostat (HTT) is open. | Alarm 59 is trig- gered by the open- ing of the Heat Ter- mination Thermo- stat (HTT) and will result in the disab- ling of the heater. | Check for 24 volts at test point TP10, if no voltage at TP10 after unit has reached set point HTT is open. | Replace HTT if defective. |
38 | AL60 Defrost Temperature Sensor (DTS) | Failure of the Defrost Temperature Sensor (DTS) to open. | Defrost Temperature Sensor (DTS) | Test the DTS; refer to Sensor Checkout Proced- ure Section 6.24.1. | Replace the DTS if defective, refer to Sensor Replacement Section 6.24.2. |
39 | AL61 Heater Current Draw Fault | Improper current draw during heat or defrost mode. | Heater(s) | While in heat or defrost mode, check for proper current draw at heater contactors, refer to ELECTRICAL DATA Section 2.3. | Replace heater(s) if defective, refer to Section 6.15.2 Evaporator Heater Removal and Replacement. |
40 | Contactor | Check voltage at heater contactor on the heater side. If no voltage present: | Replace heater contact- or if defective. | | |
41 | AL63 Current Limit | Unit operating above current limit. | Refrigeration System | Check unit for air flow restrictions. | Clean or remove any debris from coils. |
42 | Check unit for proper operation. | Repair as needed. | | | |
43 | Power supply | Confirm supply voltage/fre- quency is within specifica- tion and balanced accord- ing to ELECTRICAL DATA Section 2.3. | Correct power supply. | | |
44 | Current limit set too low. | Check current limit setting Code Cd32. | The current limit can be raised (maximum of 23 amps) using Cd32. | | |
45 | AL64 Discharge Temperature Sensor (CPDS) | Discharge Temperature sensor out of range. | Discharge temperature sensor (CPDS). | Test the CPDS; refer to TEMPERATURE SENSOR Service Section 6.24.. | Replace the CPDS if defective, refer to TEMPERATURE SENSOR Service Sec- tion 6.24. |
46 | AL65 Discharge Pressure Transducer (DPT) | Compressor Discharge Transducer is out of range. | Compressor Discharge Transducer (DPT) | Confirm accurate DPT pressure readings, refer to MANIFOLD GAUGE SET Section 6.2. | Replace DPT if defective. |
47 | AL66 (SPT) Suction Pressure Transducer, (EPT) Evaporator Pressure Transducer | Suction Pressure Transducer (SPT) out of range. | Suction Pressure Transducer (SPT) | Confirm accurate EPT and SPT pressure readings, refer to MANIFOLD GAUGE SET Section 6.2. Performing a Pre−trip 5−9 test will also check the transducers. | Replace EPT/SPT if defective. |
48 | Monitor | If the alarm persists, it may indicate a failing compressor, refer to COMPRESSOR Service Section 6.8. | | | |
49 | AL67 Humidity Sensor | Humidity Sensor (HS) reading out of range. | Humidity Sensor (HS) | Make sure the humidity sensor is properly connec- ted in the socket and the wires have not been dam- aged. | Monitor, replace HS if alarm persists. |
50 | AL68 CPC Pressure Sensor (PS3) | Condenser Pressure Transducer (CPC) out of range. | Condenser Pres- sure Transducer (CPC) | NA | Unit will disable Con- denser Pressure Control if Configured. |
51 | AL69 Suction Temp Sensor (CPSS) | Suction Temperature Sensor (CPSS) out of range. | Suction Temperature Sensor (CPSS) | Test the CPSS, refer to TEMPERATURE SENSOR Service Section 6.24. | Replace CPSS if defective, refer to TEMPERATURE SENSOR Service Section 6.24. |
52 | AL70 Secondary Supply Sensor (SRS) | Secondary Supply Sensor (SRS) is out of range. | Secondary Supply Sensor (SRS) | Perform Pre−trip P5: | If P5 passes, no further action is required. |
53 | If P5 fails, replace the defective sensor as determined by P5, refer to TEMPERATURE SENSOR Service Section 6.24. | | | | |
54 | AL71 Secondary Return Sensor (RRS) | Secondary Return Sensor (RRS) is out of range. | Secondary Return Sensor (RRS) | Perform Pre−trip P5: | If P5 passes, no further action is required. |
55 | If P5 fails, replace the defective sensor as determined by P5, refer to TEMPERATURE SENSOR Service Section 6.24. | | | | |
56 | AL72 Control Temp Out of Range | After the unit goes in− range for 30 minutes then out of range for a continuous 120 minutes. | Refrigeration System | Ensure unit is operating correctly. | Power cycle unit. Control Temperature is in In−range. Any Pre−trip mode, re- sets the timers. |
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