Carrier air conditioners are well-known throughout the world. The air conditioners of this make are distinguished by excellent ergonomics and high-performance level. The error codes for diagnostics of this equipment can be found below in the form of a table. The system can correct some breakings itself, but it does not help in all cases. Therefore, one should have such a table to hand. It allows to decipher any error code and assign repair.
Air conditioners Carrier 48VL-A as well as split are single packaged air conditioners having the gas furnace system. They use R-410 A as refrigerant. These are heat/electric cooling systems which are able to use the comfort of gas heating packaged along with efficient electric air conditioning.
| SYMPTOM | CAUSE | REMEDY |
| No Power or Hardware failure (LED OFF) | Loss of power to control module (IGC). | Check 5-amp fuse son IGC, power to unit, 24-v circuit breaker, and transformer. Units without a 24-v circuit breaker have an internal overload in the 24-v transformer. If the overload trips, allow 10 minutes for automatic reset. |
| Limit switch faults (LED 2 flashes) | High temperature limit switch is open. | Check the operation of the indoor (evaporator) fan motor. Ensure that the supply-air temperature rise is in accordance with the range on the unit nameplate. Clean or replace filters. |
| Flame sense fault (LED 3 flashes) | The IGC sensed flame that should not be present. | Reset unit. If problem persists, replace control board. |
| 4 consecutive limit switch faults (LED 4 flashes) | Inadequate airflow to unit. | Check the operation of the indoor (evaporator) fan motor and that supply-air temperature rise agrees with range on unit nameplate information. |
| Ignition lockout fault (LED 5 flashes) | Unit unsuccessfully attempted ignition for 15 minutes. | Check ignitor and flame sensor electrode spacing, gaps, etc. Ensure that fame sense and ignition wires are properly terminated. Verify that unit is obtaining proper amount of gas. |
| Pressure Switch fault (LED 6 flashes) | Open pressure switch. | Verify wiring connections to pressure switch and inducer motor. Verify pressure switch hose is tightly connected to both inducer housing and pressure switch. Verify inducer wheel is properly attached to inducer motor shaft. Verify inducer motor shaft is turning. |
| Rollout switch fault (LED 7 flashes) | Rollout switch has opened. | Rollout switch will automatically reset, but IGC will continue to lockout unit. Check gas valve operation. Ensure that induced-draft blower wheel is properly secured to motor shaft. Inspect heat exchanger. Reset unit at unit disconnect. |
| Internal control fault (LED 8 flashes) | Microprocessor has sensed an error in the software or hardware. | If error code is not cleared by resetting unit power, replace the IGC. |
| Temporary 1 hr auto reset1 (LED 9 flashes) | Electrical interference impeding IGC software | Reset 24-v. to control board or turn thermostat off, then on again. Fault will automatically reset itself in one (1) hour. |
Air conditioners Carrier 50EJ are single-package rooftop units. They provide electric cooling with electric heat option. They have indoor sections and roof curbs, which are delivered disassembled. The refrigerant of the type R-22 is used in their system.
| LED BLINKS | ERROR CODE | DESCRIPTION | TROUBLESHOOTING COMMENTS |
| 1 | Normal Operation | The expansion board and control board flash the red LED in one- second intervals when the board is operating properly. | |
| 2 | HF-13 | Compressor 1 Safety | The high or low pressure safety switch for compressor no. 1 has opened for 3 seconds. The error will be cleared and compressor no. 1 will be allowed to turn on in 15 minutes. If the safeties have been tripped 3 times in 90 minutes, compressor no. 1 will be locked out until the control board has been manually reset. |
| 3 | HF-14 | Compressor 2 Safety | The high or low pressure safety switch for compressor no. 2 has opened for 3 seconds. The error will be cleared and compressor no. 2 will be allowed to turn on in 15 minutes. If the safeties have been tripped 3 times in 90 minutes, compressor no. 2 will be locked out until the control board has been manually reset. |
| 4 | HF-15 | Thermostat Failure | The thermostat is calling for both heating and cooling at the same time. The unit will operate on a first call basis and will auto- matically reset. |
| 5 | HF-05 | SAT Thermistor Failure | The supply-air temperature (SAT) sensor has failed. First check for wiring errors, then replace sensor. |
| 6 | HF-06 | OAT Thermistor Failure | The outside-air temperature (OAT) sensor has failed. First check for wiring errors, then replace sensor. |
| 7 | HF-03 | Space Temp. Sen. Failure | The space temperature sensor has failed. First check for wiring errors, then replace sensor. |
| 8 | HF-12 | RAT Thermistor Failure | The return-air temperature (RAT) sensor has failed. Ensure that the unit is a VAV unit. If NOT a VAV unit set DIP switch position 1 to the closed position and reset power. Then check for wiring errors. Finally, replace sensor. |
| 9 | SE-05 | Loss of Communications with Expansion board | Communications between the expansion board and the control board have been interrupted. Ensure that an expansion board is installed and wired using the wire harness supplied with the expansion module. If an expansion board is not used ensure that DIP switch position 3 is in the closed position, and reset power. |
| 10 | HF-16 | Control Board Failure | Generated when hardware has failed on control board. Replace the control board. |
| 11 | HF-17 | Expansion Board Failure | Generated when hardware has failed on the expansion board. Replace the expansion board. |
Air conditioning equipment Carrier 50PD05 represent single package displacement ventilation
or single zone variable airflow rooftop units. They provide electric cooling and gas heating. The used refrigerant is R—410A.
| ALARM OR ALERT NUMBER | DESCRIPTION | ACTION TAKEN BY CONTROL | RESET METHOD | PROBABLE CAUSE |
| Digital Compressor Control Board Alarm | No action | Automatic | ||
| Compressor A1 Safety Trip | Add Strike for Circuit A | Current Sensing turned on (CS.A1 = Enable) and should be off | ||
| T051 | Service Test Compressor A1 Safety Trip | |||
| Compressor A1 Current Detected After Turnoff | Turn off all compressors | |||
| Service Test Compressor A1 Current Detected After Turnoff | ||||
| T064 | Circuit A Saturated Condensing Temp Thermistor Failure | Use OAT to control Outdoor fans | Faulty, shorted, or open thermistor caused by wiring error or loose connection. | |
| T066 | Circuit A Saturated Suction Temperature Thermistor Failure | No Cooling | Suction transducers internally forced inactive | |
| T073 | Outdoor Air Temperature Thermistor Failure | No cooling with economizer | Faulty, shorted, or open thermistor caused by wiring error or loose connection. | |
| T074 | Space Temperature Thermistor Failure | No heating or cooling | ||
| T075 | Supply Air Temperature Thermistor Failure | No cooling mode | ||
| T076 | Return Air Thermistor Failure | No differential DB crossover | ||
| T077 | Space Relative Humidity Sensor Failure | If RH.S = Yes. then no indoor humidity control | Faulty, shorted, or open sensor caused by wiring error or loose connection. | |
| T092 | Circuit A Suction Pressure Transducer Failure | Shutdown Circuit A | Manual | Faulty transducer, faulty 5-V power supply, or loose connection |
| T102 | Compressor A1 Current Sensor Failure | If CS.A1 = Enable, then no T051 current alarm | Automatic | Current Sensing turned on (CS.A1 = Enable) and should be off |
| T110 | Service Test Circuit A Loss of Charge | Shutdown Circuit A | Manual | Low refrigerant or faulty suction pressure transducer |
| T126 | Circuit A High Discharge Pressure | Automatic | An overcharged system, high outdoor ambient temperature coupled with dirty outdoor coil, plugged filter drier, or a faulty high-pressure switch. | |
| Service Test Circuit A High Discharge Pressure | ||||
| T133 | Circuit A Low Refrigerant Pressure | Add Strike for Circuit A | Low refrigerant charge, dirty filters, evaporator fan turning backwards, loose or broken fan belt, plugged filter drier, faulty transducer, excessively cold return air, or stuck open economizer when the ambient temperature is low. | |
| Service Test Circuit A Low Refrigerant Pressure | ||||
| T143 | Service Test Circuit A Failure To Pressurize | Wiring causing reverse rotation or faulty compressor | ||
| T153 | Real Timedock Hardware Failure | No time and date schedule operation | No time/date configured, software failure, or MBB failure | |
| A154 | Serial EEPROM Hardware Failure | Unit Shutdown | Software failure or MBB failure | |
| T155 | Serial EEPROM Storage Failure Error | Unit operation errors | ||
| A156 | Critical Serial EEPROM Storage Fail Error | Unit Shutdown | ||
| A’D Hardware Failure | Manual | |||
| A163 | Circuit A Down Due to Failure | Shutdown Circuit A | Circuit has 3 strikes or has been locked out by another alarm | |
| Service Test Circuit A Down Due to Failure | Circuit has 1 strike or has been locked out by another alarm | |||
| T178 | Loss of Communication with the Capacity Control Board | Unit shutdown -HVAC disable | Automatic | Communication wiring problem with AUX1 or faulty MBB. ECB. orAUXI |
| T179 | Loss of communication with the Economizer Control Board | No economizer operation | Communication wiring problem with ECB or faulty MBB. ECB. orAUXI | |
| T180 | Loss of communication with the Economizer Actuator | Communication wiring problem with actuator. | ||
| A200 | Linkage Timeout Error Comm Failure | No Linkage Operation fall back to local SPT | Received a table write from Linkage before, now not receiving any linked commands | |
| A404 | Fire Shutdown | Unit Shutdown | Smoke detected by smoke detector | |
| T408 | Dirty Filter | Alert Generated | Dirty Filter | |
| T409 | Fan Status Switch ON. Fan Contactor OFF | If IDF.F = Yes, then Unit Shutdown | If IDF.F = YES, then Manual, otherwise automatic | Bad Fan Status Switch. Configuration incorrect. |
| Fan Status Switch OFF. Fan Contactor ON | If IDF.F = YES. then Manual, otherwise automatic | Tripped Circuit Breaker. Broken belt. Bad indoor fan motor. Configuration incorrect. Bad fan status switch. | ||
| T414 | Economizer Damper Actuator Out of Calibration | Alert Generated | Automatic | Calibrate economizer (E.CAL). If problem still exist then determine what is limiting economizer rotation. |
| Economizer Damper Actuator Torque Above Load Limit | Actuator load too high. Check damper load. | |||
| Economizer Damper Actuator Hunting Excessively | Damper position changing too quickly. | |||
| Economizer Damper Stuck or Jammed | No economizer motion. Check damper blades, gears, and actuator. | |||
| Economizer Damper Actuator Mechanical Failure | Check actuator and replace if necessary. | |||
| Economizer Damper Actuator Direction Switch Wrong | Actuator direction control switch (CCW, CW) wrong. | |||
| T415 | IAQ Input Out of Range | No IAQ Operations | Bad sensor, bad wiring, or sensor configured incorrectly. | |
| T416 | OAQ Input Out of Range | Bad sensor, bad wiring, or sensor configured incorrectly. |
Air conditioning equipment Carrier xpower Blue II 42KCL109313G belongs to inverter series. These units have indoor and outdoor blocks. They do not provide heating function. The refrigerant that can be used in their system is R410A.
| Display | LED STATUS |
| EO | EEPROM parameter error |
| E1 | Indoor unit and outdoor unit communication protection |
| E2 | Zero-crossing signal error |
| E3 | Indoor fan speed has been out of control |
| E5 | Open or short circuit of outdoor temperature sensor or outdoor unit EEPROM parameter error |
| E6 | Open or short circuit of room or evaporator coil temperature sensor |
| PO | IPM malfunction or IGBT over-strong current protection |
| P1 | Over voltage or too low voltage protection |
| P2 | Temperature protection of compressor top. |
| P4 | Inverter compressor drive error |
Air conditioners Carrier MOTORMASTER 4850P3 belong to low ambient operation units. They are fit with MOTORMASTER V control accessory, which makes its control more comfortable and convenient.
| CODE | DESCRIPTION | RESET METHOD | PROBABLE CAUSE | CORRECTIVE ACTION |
| AF | High Temperature Fault | Automatic | Ambient temperature is too high; Cooling fan has failed (if equipped). | Check cooling fan operation. |
| CF | Control Fault | Manual | A blank EPM, or an EPM with corrupted data has been installed. | Perform a factory reset using Parameter 48 PROGRAM SELECTION. |
| cF | Incompatibility Fault | An EPM with an incompatible parameter version has been installed. | Either remove the EPM or perform a factory reset (Parameter 48) to change the parameter version of the EPM to match the parameter version of the drive. | |
| F1 | EPM Fault | The EPM is missing or damaged. | Install EPM or replace with new EPM. | |
| F2—F9 Fo | Internal Faults | The control board has sensed a problem | Consult factory. | |
| GF | Data Fault | User data and Carrier defaults in the EPM are corrupted. | Restore factory defaults by toggling P48 to another mode. Then set P48 to desired mode to restore all defaults for that mode. If that does not work, replace EPM. | |
| HF | High DC Bus Voltage Fault | Automatic | Line voltage is too high; Deceleration rate is too fast; Overhauling load. | Check line voltage — set P01 appropriately. |
| JF | Serial Fault | The watchdog timer has timed out, indicating that the serial link has been lost. | Check serial connection (computer). Check settings for P15. Check settings in communication software to match P15. | |
| LF | Low DC Bus Voltage Fault | Line voltage is too low. | Check line voltage — set P01 appropriately. | |
| OF | Output Transistor Fault | Phase to phase or phase to ground short circuit on the output; Failed output transistor; Boost settings are too high; Acceleration rate is too fast. | Reduce boost or increase acceleration values. If unsuccessful, replace drive. | |
| PF | Current Overload Fault | VFD is undersized for the application; Mechanical problem with the driven equipment. | Check line voltage set P01 appropriately. Check for dirty coils. Check for motor bearing failure. | |
| SF | Single-phase Fault | Single-phase input power has been applied to a three-phase drive. | Check input power phasing. | |
| Drive displays “—“ even though drive should be running | Start Contact is Not Closed | Start contact is missing or not functioning. | Check fan relay. | |
| VFD flashes “—” and LCS | Start contact not closed. | Check FR for closed contact. | ||
| VFD flashes 57 (or 47) and LCS | Speed Signal Lost | Speed signal lost. Drive will operate at 57 (or 47) Hz until reset or loss of start command. Resetting requires cycling start command (or power). | Transducer signal lost. Check VDC signal between TB5 and TB2. Should be in range of 0.5V to 4.5V. 5VDC output should be present between TB6 and TB2. |
Air conditioning equipment Carrier GEMINI 38APD025-100 represents commercial air-cooled condensing units with COMFORTLINK controls. Each unit has its display module. It is used for accessing unit information, reading sensor values and testing the unit.
| ALARM/ ALERT CODE | ALARM OR ALERT | DESCRIPTION | WHY WAS THIS ALARM GENERATED? | ACTION TAKEN BY CONTROL | RESET METHOD |
| T048 | Alert | Circuit A Compressor Availability Alert | Two compressors on circuit failed | Circuit shut down | Manual |
| T049 | Circuit B Compressor Availability Alert | Two compressors on circuit failed | |||
| T051.T052, T053 | Circuit A Compressor A1 .A2.A3 Failure | Respective current sensor board (CSB) feedback signal does not match relay state | Respective compressor shut down in Circuit A. | ||
| TOSS, T056, T057 | Circuit B Compressor B1 .B2.B3 Failure | Respective compressor shut down in Circuit B. | |||
| A051, A052, A053 | Alarm | Circuit A Compressor A1 .A2.A3 Failure | Respective current sensor board (CSB) feedback signal is ON when the compressor should be off | Unit shut down | |
| A055, A056, A057 | Circuit B Compressor B1 .B2.B3 Failure | ||||
| A060 | Supply Air Thermistor Failure | Thermistor outside range of -40 to 245 F (-40 to 118 C) | Automatic | ||
| A060 | Supply Air Temperature Update not received | Temperature not updated during 3 minutes | |||
| A061 | Return Air Thermistor Failure | Thermistor outside range of -40 to 245 F (-40 to 118 C) | |||
| A061 | Return Air Temperature Update not received | Temperature not updated during 3 minutes | |||
| T068 | Alert | Circuit A Return Gas Thermistor Failure | Thermistor is outside range of -40 to 245 F (-40 to 118 C) | Circuit shut down | |
| T069 | Circuit B Return Gas Thermistor Failure | ||||
| T073 | Outside Air Thermistor Failure | Temperature reset disabled. Unit runs under normal control/set points. | |||
| T074 | Space Temperature Thermistor Failure | ||||
| T090 | Circuit A Discharge Pres- sure Transducer Failure | The pressure is outside the range of 0.0 to 667.0 psig | Circuit A shut down | ||
| T091 | Circuit B Discharge Pres- sure Transducer Failure | Circuit B shut down | |||
| T092 | Circuit A Suction Pressure Transducer Failure | The pressure is outside the range of 0.0 to 420.0 psig | Circuit A shut down | ||
| T093 | Circuit B Suction Pressure Transducer Failure | Circuit B shut down | |||
| T094 | Discharge Gas Thermistor Failure | Discharge thermistor (DTT) is either open or shorted | Digital compressor shut down. | ||
| T110 | Circuit A Loss of Charge | If the compressors are off and discharge pressure reading is less than 26 psig for 30 sec. | Circuit not allowed to start. | Manual | |
| T111 | Circuit B Loss of Charge | ||||
| T112 | Circuit A High Saturated Suction Temperature | Circuit is on and saturated suction temperature is greater than 70 F (15.6 C) for 5 minutes | Circuit shut down | ||
| T113 | Circuit B High Saturated Suction Temperature | Circuit is on and saturated suction temperature is greater than 70 F (15.6 C) for 5 minutes | |||
| T114 | Circuit A Low Suction Superheat | Suction superheat is less than 5 F (2.8 C) for 5 minutes. | Circuit A is shut down after pump down complete. | Automatic after first daily occurrence, manual thereafter | |
| T115 | Circuit B Low Suction Superheat | Suction superheat is less than 5 F (2.8 C) for 5 minutes. | Circuit B is shut down after pump down complete. | ||
| T118 | High Discharge Gas Temperature | Discharge Thermistor (DTT) reading is greater than 250 F | Compressor A1 shutdown | Automatic | |
| A118 | Alarm | 3 Discharge Gas Temperature alarms occur within a day | Compressor A1 shutdown | Manual | |
| P120 | Alert | Circuit A Low Saturated Suction | SSTA is less than 20 F for 4 minutes, less than 10 F for 2 minutes, less than 0° F for 1 minute or less than -20 F for 20 seconds continuously | Circuit A will remove one compressor stage. | Automatic |
| T120 | Circuit A shut down | Automatic unless 3rd strike. | |||
| A120 | Alarm | Manual | |||
| P121 | Alert | Circuit B will remove one compressor stage. | Automatic | ||
| T121 | Circuit B Low Saturated Suction | Circuit B shut down | Automatic unless 3rd strike. | ||
| A121 | Alarm | Manual | |||
| T122 | Alert | High Pressure Switch Trip Circuit A | High Pressure A Switch Input open to MBB | Circuit shut down | |
| T123 | High Pressure Switch Trip Circuit B | High Pressure B Switch Input open to MBB | |||
| T126 | Circuit A High Discharge Pressure | SCTA >150 F | Automatic, only after first 3 daily occurrences. | ||
| A126 | Alarm | Manual | |||
| T127 | Alert | Circuit B High Discharge Pressure | SCTB >150 F | Automatic, only after first 3 daily occurrences | |
| A127 | Alarm | Circuit B High Discharge Pressure | SCTB >150 F | Manual | |
| A140 | Reverse Rotation Detected | Incoming unit power leads not phased correctly | Unit shut down. | ||
| A150 | Emergency Stop | CCN emergency stop command received | Unit shutdown without going through pump down. | Automatic once CCN command for EMSTOP returns to normal | |
| A151 | Illegal Configuration | One or more illegal configurations exists. | Unit is not allowed to start. | Manual once configuration errors are corrected | |
| T153 | Alert | Real Time Clock Hardware Failure | Internal clock on MBB fails | Occupancy schedule will not be used. Unit defaults to Local On mode. | Automatic when correct clock control restarts. |
| A154 | Alarm | Serial EEPROM Hardware Failure | Hardware failure with MBB | Unit is unable to run. | Manual |
| T155 | Alert | Serial EEPROM Storage Failure | Configuration/storage failure with MBB | No action | |
| A156 | Alarm | Critical Serial EEPROM Storage Failure | Unit is not allowed to run. | ||
| A157 | A/D Hardware Failure | Hardware failure with peripheral device | |||
| A170 | Loss of Communication with CXB | MBB loses communication with CXB | CXB functions disabled | Automatic | |
| A173 | Loss of Communication with EMM | MBB loses communication with EMM | 4 to 20 mA temperature reset disabled. Demand Limit set to 100%. 4 to 20 mA set point disabled. | ||
| T174 | Alert | 4 to 20 mA Cooling Set Point/Desired % Capacity Input Failure | If configured with EMM and input less than 2 mA or greater than 22 mA | Set point function/% capacity function disabled. | |
| T176 | 4 to 20 mA Temperature Reset Input Failure | Reset function disabled. Unit returns to normal set point control. | |||
| T177 | 4 to 20 mA Demand Limit Input Failure | Demand limit function disabled. Unit returns to 100% demand limit control. | |||
| A200 | Alarm | Fan Status Switch 1 Open | Alarm is generated when fan status switch 1 is open when the unit is in an ON state | Unit not allowed to start | |
| T201 | Alert | Fan Status Switch 1 is open with Dual TSTAT configuration | Alert is generated when fan status switch 1 is open when Y1 or Y2 are closed | Circuit A is not allowed to run | |
| T202 | Fan Status Switch 2 is open with Dual TSTAT configuration | Alert is generated when fan status switch 1 is open when Y3 or Y4 are closed | |||
| T303 | Condenser Coil Maintenance Due | Coil Service Countdown (C.L.DN) expired. Complete condenser coil cleaning and enter ‘YES’ for Coil Maintenance Done (C.L.MN) item. | None | ||
| T500 | Current Sensor Board A1 Failure | Alert occurs when CSB output is a constant high value | Compressor A1 shut down | ||
| T501 | Current Sensor Board A2 Failure | Compressor A2 shut down | |||
| T502 | Current Sensor Board A3 Failure | Compressor A3 shut down | |||
| T503 | Current Sensor Board B1 Failure | Compressor B1 shut down | |||
| T504 | Current Sensor Board B2 Failure | Compressor B2 shut down | |||
| T505 | Current Sensor Board B3 Failure | Compressor B3 shut down |