Alarm Codes, Descriptions and Corrective Actions

Note Sensors used with the MP3000/MP3000a Controller do not require calibration. Check sensor resistance with an ohmmeter.

  • Shutdown Alarm (Level 1 Alarm): Alarm light on display flashes and unit stops. Correct alarm condition and acknowledge alarm before restarting.

  • Check Alarm (Level 2 Alarm): Alarm light on display flashes until alarm is acknowledged.

  • Event Log (Level 3 Alarm): Alarm is recorded in datalogger only (inspect event log).

Model CRR DF - Alarm Codes, Descriptions and Corrective Actions

Code Description Corrective Action
00 Supply Air Sensor Open Circuit (Check Alarm)

  • Sensor circuit resistance higher than 100,000 ohms.

  • Temperature below -80 C (-112 F).

  • Indicates:

    • Open circuit to sensor

    • Defective or wrong sensor

    • Defective relay board

    • Defective cable No. 1

    • Defective controller

  • Check sensor resistance between pins 1 and 2 on plug J15. Resistance must be 1,000 ohms at 25 C (77 F).

  • Check cable No. 1 between controller and relay board.

  • Check evaporator airflow.
01 Supply Air Sensor Short Circuit (Check Alarm)

  • Sensor circuit resistance lower than 200 ohms.

  • Temperature above 80 C (176 F).

  • Indicates:

    • Open circuit to sensor

    • Defective or wrong sensor

    • Defective relay board

    • Defective cable No. 1

    • Defective controller

  • Check sensor resistance between pins 1 and 2 on plug J15. Resistance must be 1000 ohms at 25 C (77 F).

  • Check cable No. 1 between controller and relay board.
02 Return Air Sensor Open Circuit (Check Alarm)

  • Sensor circuit resistance higher than 100,000 ohms.

  • Temperature below -80 C (-112 F).

  • Indicates:

    • Open circuit to sensor

    • Defective or wrong sensor

    • Defective relay board

    • Defective controller

  • Check sensor resistance between pins 3 and 4 on plug J15. Resistance must be 1000 ohms at 25 C (77 F).

  • Check cable No. 1 between controller and relay board.
03 Return Air Sensor Short Circuit (Check Alarm)

  • Sensor circuit resistance lower than 200 ohms.

  • Temperature above 80 C (176 F).

  • Indicates:

    • Open circuit to sensor

    • Defective or wrong sensor

    • Defective relay board

    • Defective cable No. 1

    • Defective controller

  • Check sensor resistance between pins 3 and 4 on plug J15. Resistance must be 1000 ohms at 25 C (77 F).

  • Check cable No. 1 between controller and relay board.
04 Evaporator Coil Sensor Open Circuit (Check Alarm)

  • Sensor circuit resistance higher than 100,000 ohms.

  • Temperature below -80 C (-112 F).

  • Indicates:

    • Open circuit to sensor

    • Defective or wrong sensor

    • Defective relay board

    • Defective cable No. 1

    • Defective controller

    • Low evaporator coil temperature

  • Check sensor resistance between pins 5 and 6 on plug J15. Resistance must be 1,000 ohms at 25 C (77 F).

  • Check cable No. 1 between controller and relay board.

  • Check evaporator airflow.
05 Evaporator Coil Sensor Short Circuit (Check Alarm)

  • Sensor circuit resistance lower than 200 ohms.

  • Temperature above 80 C (176 F).

  • Indicates:

    • Open circuit to sensor

    • Defective or wrong sensor

    • Defective relay board

    • Defective cable No. 1

    • Defective controller

  • Check sensor resistance between pins 5 and 6 on plug J15. Resistance must be 1,000 ohms at 25 C (77 F).

  • Check cable No. 1 between controller and relay board.
06* R-134 Compressor Current Too High (Check Alarm)

  • Occurs during Pretrip (PTI) only.

  • Compressor power consumption is higher than approximately 13 amps.

  • Indicates:

    • Defective compressor or valve plate

    • Defective volt or amp meter on relay board

    • Inaccurate ambient temperature measurement

    • Out of range power supply

  • Start “Manual Function Test”. Make sure the compressor and condenser fan are operating. Check compressor volts and amps.

  • Check power supply volts.

  • Check ambient sensor.
07* R-134 Compressor Current Too Low (Check Alarm)

  • Occurs during Pretrip (PTI) only.

  • Compressor power consumption is higher than approximately 7 amps.

  • Indicates:

    • Defective or open fuse CB 6A, high pressure cutout switch or connection in plug J19 between pins 7 & 8

    • No signal on plug J11 on pin 8

    • Defective compressor relay

    • Defective volt or amp meter on relay board

    • Low R-134a refrigerant charge

    • Defective R-134a compressor or valve plate

  • Start “Manual Function Test”. Make sure the compressor relay energizes. If relay does NOT energize and the LED above the compressor relay is NOT ON, check for a defective cable No. 2, main relay board or controller.

  • Check discharge and suction pressure gauge readings on R-134a system. Evaluate readings based on current cargo and ambient temperatures.

  • Check compressor volts and amps.

  • Check power supply volts.
*If both alarms 06 and 07 are activated, the alarms are caused by a large difference in measured amps. Start “Manual Function Test” and start the R-134a compressor and condenser fan. Check the compressor amps measurement. If necessary, check the resistance of the compressor motor windings.
10* Heater Current Too High (Check Alarm)

  • Occurs during Pretrip (PTI) only.

  • Heater power consumption is higher than approximately 9 amps and lower than 13 amps.

  • Indicates:

    • Incorrect heaters or heater connections

    • Defective volt or amp meter on relay board

    • Defective heater element

  • Start “Manual Function Test” and turn heaters ON. Check current draw on each phase. Current draw should be about 9.0 amps on each phase at 380V (10.4 amps at 460V).
11* Heater Current Too Low (Check Alarm)

  • Occurs during Pretrip (PTI) only.

  • Heater power consumption is lower than approximately 6 to 9 amps, depending on voltage.

  • Indicates:

    • Incorrect heaters or heater connections

    • Defective heater elements or heat relay

    • Defective wire connections

    • Defective high evaporator temperature switch

  • Start “Manual Function Test” and turn heaters ON. Check current draw on each phase. Current draw should be 4.5 amps on each phase at 380V.

  • If heat relay fails to energize, check evaporator high temperature switch. Switch should be closed at temperatures below 54 C (130 F); there should be continuity between pins 5 & 6 in plug J19.

  • Check power supply volts and amps.

  • Check heater element resistance between H1 and H2, H2 and H3, and H1 and H3. Resistance readings should be equal (approximately 50 ohms).
*If both alarms 10 and 11 are activated, the alarms are caused by a large difference in measured amps. Start “Manual Function Test” and energize the heaters. Check the heater amps measurement. If necessary, isolate and check the resistance of each individual heater element.
14* Evaporator Fan Low Speed Current Too High (Check Alarm)

  • Occurs during Pretrip (PTI) only.

  • Evaporator fan power consumption is higher than approximately 2.6 to 2.9 amps, depending on voltage.

  • Indicates:

    • Defective or stuck evaporator fan motor

    • Incorrect motor or motor connections

    • Motor high and low speed connection are interchanged

    • Defective volt or amp meter on relay board

  • Open evaporator door and make sure all fans rotate freely.

  • Start “Manual Function Test” and set evaporator motors to low speed. Make sure all fans start on low speed.

  • Check fan motor volts and amps.

  • Check power supply volts and amps.
15* Evaporator Fan Low Speed Current Too Low (Check Alarm)

  • Occurs during Pretrip (PTI) only.

  • Evaporator fan power consumption is lower than approximately 1.0 to 1.2 amps, depending on voltage.

  • Indicates:

    • Defective evaporator fan motor relay

    • Defective or open fan motor internal over temperature protection switch

    • Defective volt or amp meter on relay board

    • Incorrect motor or motor connections

  • Open evaporator door and make sure all fans rotate freely.

  • Start “Manual Function Test” and set evaporator motors to low speed. Make sure all fans start on low speed.

  • Check fan motor volts and amps.

  • Check power supply volts and amps.
*If both alarms 14 and 15 are activated, the alarms are caused by a large difference in measured amps. Start “Manual Function Test” and start the evaporator fans. Check the evaporator fan amps measurement. If necessary, check the resistance in the motors between L1, L2 and L3, and L1 and L3. Resistance readings should be equal (approximately 30 Ohms, total of 3 motors).
16* Condenser Fan Current Too High (Check Alarm)

  • Occurs during Pretrip (PTI) only.

  • Condenser fan power consumption is higher than approximately 1.25 amps, depending on voltage

  • Indicates:

    • Defective or stuck condenser fan motor

    • Defective volt or amp meter on relay board

    • Incorrect motor or motor connections

  • Start “Manual Function Test” and set condenser fan motor to ON. Make sure the fan starts.

  • Check fan motor volts and amps.
17* Condenser Fan Current Too Low (Check Alarm)

  • Occurs during Pretrip (PTI) only.

  • Condenser fan power consumption is lower than approximately 0.7 amps, depending on voltage).

  • Indicates:

    • Defective condenser fan motor relay

    • Defective or open fan motor internal over temperature protection switch

    • Defective volt or amp meter on relay board

  • Start “Manual Function Test” and set condenser fan motor to ON. Make sure the fan starts.

  • Check fan motor volts and amps.

  • Check power supply volts and amps.
18

  • One or more frequency inputs are missing for more than 20 seconds.

  • Indicates:

    • One phase on power line is missing

    • Defective fuse on relay board

    • Defective digital inputs on relay board

  • Enter “Data” menu and view voltage reading on each phase.

  • Check all fuses. Check cable No. 1 on relay board.

  • Replace relay board. Check voltage reading on each phase.
*If both alarms 16 and 17 are activated, the alarms are caused by a large difference in measured amps. Start “Manual Function Test” and start the condenser fan. Check the condenser fan amps measurement. If necessary, check the resistance in the motor between L1 and L2, L2 and L3, and L1 and L3. Resistance readings should be equal (approximately 10 Ohms).
19 Temperature Too Far from Setpoint (Check Alarm)

  • After 80 minutes of operation, return air temperature is not in-range and does not approach setpoint by 0.1 C/hr.

  • Indicates:

    • Ice or frost on evaporator coil

    • Low refrigerant charge

    • Container air leakage (doors open)

  • Press SUP/RET key to check supply and return air sensor temperatures. Compare temperatures to evaluate unit cooling capacity and performance. Temperature difference should be 4 C to 6 C.

  • Open evaporator door. Inspect coil for ice or frost and initiate manual defrost if necessary.

    Check refrigerant charge of R-23 and R-134a systems.
Note This alarm can be activated if the supply or temperature does approach setpoint.
20 Defrost Time Too Long (Check Alarm)

  • Heat signal has been on for more than 90 minutes (120 minutes if power supply below 55 Hz) during Defrost.

  • Indicates:

    • Defective heater elements

    • Defective heat relay

    • Evaporator sensor placed wrong

  • Initiate a manual defrost and check amperage draw and evaporator coil temperature. Evaluate defrost performance.

  • Open evaporator door and check location of evaporator coil sensor.

Note This alarm can be activated at low voltage and very low box temperature conditions, even under normal operating conditions.
22 Capacity Test 1 Error (Check Alarm)

  • Occurs during pre-trip (PTI) test only.

  • Return air temperature does not reach -30 C (22 F) within 4 hours.

  • Indicates:

    • Incorrect refrigeration system operation

    • Container door is open

    • Container is not empty

    • Incorrect connection of return air sensor

  • Open evaporator door and inspect evaporator fan rotation. Make sure fans are rotating correctly on low speed.

  • Operate unit on Cool and check discharge and suction pressure gauge readings on both the R-23 and R-134a refrigeration systems. Check the refrigerant charge of the R-23 and R-134a systems.

  • Check the return sensor connections.
23 Capacity Test 2 Error (Check Alarm)

  • Occurs during pre-trip (PTI) test only.

  • Return air temperature does not reach -55 C (-67 F) within 6 hours.

  • ndicates:

    • Incorrect refrigeration system operation

    • Container door is open

    • Container is not empty

    • Incorrect connection of return air sensor

  • Open evaporator door and inspect evaporator fan rotation. Make sure fans are rotating correctly on low speed.

  • Operate unit on Cool and check discharge and suction pressure gauge readings on both the R-23 and R-134a refrigeration systems. Check the refrigerant charge of the R-23 and R-134a systems.

  • Check the return sensor connections.
34 Ambient Air Sensor Open Circuit (Check Alarm)

  • Sensor circuit resistance is higher than 100,000 ohms.

  • Temperature is below -70 C (-94 F).

  • Indicates:

    • Open circuit to sensor

    • Defective or wrong sensor

    • Defective relay board

    • Defective cable No. 1

    • Defective controller

  • Check sensor resistance between pins 13 and 14 on plug J15. Resistance must be 1,000 ohms at 25 C (77 F).

  • Check cable No. 1 between controller and relay board.
35 Ambient Air Sensor Short Circuit (Check Alarm)

  • Sensor circuit resistance is lower than 200 ohms.

  • Temperature is above 80 C (176 F).

  • Indicates:

    • Short circuit to sensor

    • Defective or wrong sensor

    • Defective relay board

    • Defective cable No. 1

    • Defective controller

  • Check sensor resistance between pins 13 and 14 on plug J15. Resistance must be 1,000 ohms at 25 C (77 F).

  • Check cable No. 1 between controller and relay board.
43 Return Air Temperature Too High (Check Alarm)

  • Return air temperature increases above 35 C (95 F) during defrost.

  • Indicates:

    • Defective return air or evaporator coil sensor

    • Return air and evaporator coil sensor connections are reversed

  • Check for sensor alarm codes.

  • Check supply and return sensor connections and locations.
52 Probe Error (Check Alarm)

  • Occurs during Pretrip (PTI) test only.

  • Temperature difference between supply air, return air or evaporator coil sensor is too high (3 C maximum)

  • Indicates:

    • Indication error on one of the sensors

    • Supply air sensor not placed in airflow stream

  • Check sensor connections. Check sensor resistance of each sensor. Resistance must be 1,000 ohms at 25 C (77 F).

  • Check supply air sensor locations.
56 Compressor Temperature Too High (Shutdown Alarm)

  • R-134a compressor discharge line temperature is above 130 C (266 F). R-134a compressor operation should resume when discharge line temperature decreases below 90 C (194 F); or R-23 compressor discharge line temperature is above 138 C (280 F). R-23 compressor operation should resume when discharge line temperature decreases below 138 C (280 F).

  • Indicates:

    • Air in refrigeration system

    • Low refrigerant charge in R-134a system

    • R-134a Only: Defective compressor or valve plate

    • Wrong or defective sensor

  • Operate unit on Cool and check discharge and suction pressure gauge readings on R-134a refrigeration system. Check refrigerant charge of R-134a system and R-23 system.

  • Check sensor resistance. Resistance must be 100,000 ohms at 25 C (77 F).

  • Check discharge line temperature with a separate electronic thermometer and compare to “HIGH PR TEMP” showing in the View submenu of controller for both the R-134a compressor and the R-23 compressor.
58 Phase Sensor Error (Check Alarm)

  • Occurs during Pre-trip (PTI) test only.

  • During Phase Sensor Test, amperage difference between correct and wrong condenser fan rotation is more than 0.2 amps.

  • Indicates:

    • Defective relay board

    • Defective relay board cable No. 2

    • Defective phase relay

  • Start “Manual Function Test” and view current display for each phase to determine if each phase sensor relay is receiving a signal. Change incoming power phase. Verify that the phase relays respond correctly.
59 Delta Current Error (Log Alarm)

  • Power consumption is More than 50% above or below (Min 0,8 Amp).

  • Indicates:

    • Open connection on one phase of power supply to a 3-phase unit component including R-134a compressor or R-23 compressor.

  • Start manual function test one by one to verify correct current draw for all components and current draw reading of 0 Amp when component is disengaged.
97 Compressor Sensor Open Circuit (Log Alarm)

  • Sensor circuit resistance is higher than 10,000,000 ohms on R-134a or R-23 compressor.

  • Temperature below -30 C (-22 F).

  • Indicates:

    • Open circuit to sensor

    • Defective or wrong sensor

    • Defective relay board

    • Defective cable No. 1

    • Defective controller

  • Check sensor resistance between pins 9 and 10 on plug J15 for R-134a compressor sensor and between pins 11 and 12 on plug J15 for R-23 compressor. Resistance must be 100,000 ohms at 25 C (77 F).

  • Check cable No. 1 between controller and relay board.

Note Unit will operate normally without compressor sensor. However, controller compressor high temperature protection is not active.
98 Compressor Sensor Short Circuit (Log Alarm)

  • Sensor circuit resistance lower than 200 ohms.

  • Temperature above 180 C (356 F).

  • Indicates:

    • Short circuit to sensor

    • Defective or wrong sensor

    • Defective relay board

    • Defective cable No. 1

    • Defective controller

  • Check sensor resistance between pins 9 and 10 on plug J15. Resistance must be 100,000 ohms at 25 C (77 F).

  • Check cable No. 1 between controller and relay board.
112 Zero Current Too High (Check Alarm)

  • Ground (zero current) circuit 30 milliamps.

  • Indicates:

    • Defective motor or heater insulation to ground

  • Start “Manual Function Test” and operate each motor and heater separately. Note when alarm occurs.
Parent topic: Diagnostics