Error Codes & FAQ

Quickly search for an error code:

High Wall (C-Series)

High Wall (LC)

Multi-Zone (High Wall Unit)

Multi-Zone (Cassette, Floor & Ceiling, Slim Duct)

Inverter Ducted System IDU

Inverter Ducted System ODU

L4
IPM fault of compressor drive module
  • Compressor drive module damage
Multi-Zone (High Wall Unit)
L4
Compressor driver module IPM failure
  • Compressor drive module damage
High Wall (C-Series)
L5
Compressor drive PFC hardware protection
  • Damage of the PFC circuit components
  • Reactor damage
Multi-Zone (High Wall Unit)
L5
PFC over-current hardware protection
  • Damage of the PFC circuit components
  • Reactor damage
High Wall (C-Series)
L6
Compressor drive PFC software protection
  • Excessive running current of the unit
  • Voltage drops abruptly during operation
Multi-Zone (High Wall Unit)
L6
PFC over-current software protection
  • Excessive running current of the unit
  • Voltage drops abruptly during operation
High Wall (C-Series)
L7
Current detection AD abnormal protection
  • Sensor damage of compressor IPM module
High Wall (C-Series)
L7
AD abnormal protection for compressor current detection
  • Sensor damage of compressor IPM module
Multi-Zone (High Wall Unit)
L8
Compressor superpower protection
  • Sampling resistance damage
  • Excessive operating power of compressor
Multi-Zone (High Wall Unit)
L8
IPM temperature sensor fault
  • Sampling resistance damage
  • Excessive operating power of compressor
High Wall (C-Series)
L9
IPM temperature sensor fault
  • Compressor IPM module sensor damage
  • Poor contact between compressor IPM module and radiator
Multi-Zone (High Wall Unit)
L9
IPM temperature sensor failure
  • Compressor IPM module sensor damage
  • Poor contact between compressor IPM module and radiator
High Wall (C-Series)
LA
Compressor start-up failure
High Wall (C-Series)
LA
Compressor failed to start
  • Compressor power line not connected
  • Compressor sequence connection error
  • Damage of compressor
Multi-Zone (High Wall Unit)
LC
PFC current detection AD abnormal protection
High Wall (C-Series)
LC
Compressor drive PFC (Power Factor Correction) protection
  • Damage of the PFC circuit components
  • Reactor damaged
Multi-Zone (High Wall Unit)
LD
DC fan current sense AD abnormal protection
High Wall (C-Series)
LD
Fault with the fan motor of outdoor unit
  • Damage of motor
Multi-Zone (High Wall Unit)
LE
DC fan phase loss protection
High Wall (C-Series)
LE
Fault with the fan motor of outdoor unit
  • Damage of motor
Multi-Zone (High Wall Unit)
LF
DC fan out-of-step protection
High Wall (C-Series)
LF
Fault with the fan motor of outdoor unit
  • Damage of motor
Multi-Zone (High Wall Unit)
LH
DC fan IPM protection
High Wall (C-Series)
LH
IPM (Intelligent Power Module) protection of outdoor DC fan drive modular
  • The IPM device of DC motor is faulty
Multi-Zone (High Wall Unit)
Light blinks 10 times
  • Fault with over load protection of IDU in cooling mode
Inverter Ducted System ODU
Light blinks 13 times
  • Fault with the over-electric current protection
Inverter Ducted System ODU
Light blinks 17 times
  • Fault with the low voltage protection
Inverter Ducted System ODU
Light blinks 18 times
  • Fault with the Environmental temperature sensor (Tao) on the ODU
Inverter Ducted System ODU
Light blinks 19 times
  • Fault with the temperature sensor (Tcm) on the ODU
Inverter Ducted System ODU
Light blinks 2 times
  • Communication failure between IDU and ODU
Inverter Ducted System ODU
Light blinks 20 times
  • Fault with the discharge temperature sensor
Inverter Ducted System ODU
Light blinks 21 times
  • Protection of compressor driving module for excessive temperature
Inverter Ducted System ODU
Light blinks 22 times
  • Fault with anti-high temperature protection of IDU in heating mode
Inverter Ducted System ODU
Light blinks 24 times
  • Fault with fan motor of ODU - Fan 2
Inverter Ducted System ODU
Light blinks 26 times
  • Low pressure switch protection
Inverter Ducted System ODU
Light blinks 28 times
  • Fault with the suction temperature Sensor
Inverter Ducted System ODU
Light blinks 29 times
  • High pressure switch protection
Inverter Ducted System ODU
Light blinks 30 times
  • Fault of four-way valve
Inverter Ducted System ODU
Light blinks 31 times
  • Fault with the defrosting temperature Sensor on the outdoor unit
  • Fault with the low-pressure switch
Inverter Ducted System ODU
Light blinks 4 times
  • Compressor failed to start
Inverter Ducted System ODU
Light blinks 6 times
  • Fault with fan motor of ODU - Fan 1
Inverter Ducted System ODU
Light blinks 7 times
  • Fault with fan motor of ODU
Inverter Ducted System ODU
Light blinks 9 times
  • Compressor discharge temperature too high protection
Inverter Ducted System ODU
Light stays on for 5 minutes
  • Normal (485/24V signal not received)
Inverter Ducted System IDU
Light stays on for 5 minutes
  • Normal, compressor shut down (IDU and ODU do not use 485 communication)
Inverter Ducted System ODU
Lights blink 1 time and stop for 8 seconds
  • 485 Communication abnormal between the ODU and IDU
Inverter Ducted System IDU
Lights blink 10 times and stop for 8 seconds
  • Fault with ODU
Inverter Ducted System IDU
Lights blink 2 times and stop for 8 seconds
  • Fault with the wired controller communication
Inverter Ducted System IDU
Lights blink 3 times and stop for 8 seconds
  • Fault with the fan motor of IDU
Inverter Ducted System IDU
Lights blink 4 times and stop for 8 seconds
  • Fault with the refrigerant sensor
Inverter Ducted System IDU
Lights blink 5 times and stop for 8 seconds
  • Refrigerant leakage protection
Inverter Ducted System IDU
Lights blink 6 times and stop for 8 seconds
  • Fault with the room temperature sensor on the IDU
Inverter Ducted System IDU
Lights blink 7 times and stop for 8 seconds
  • Fault with the temperature sensor in the Middle evaporator of IDU
Inverter Ducted System IDU
Lights blink 8 times and stop for 8 seconds
  • IDU coil pipe inlet temperature sensor failure
  • IDU coil pipe outlet temperature sensor failure
Inverter Ducted System IDU
Lights blink 9 times and stop for 8 seconds
  • Operation mode abnormal
Inverter Ducted System IDU
No light
  • Normal (485/24V signal received)
Inverter Ducted System IDU
No light
  • Normal, compressor shut down (IDU and ODU using 485 communication)
Inverter Ducted System ODU
No light
  • Normal compressor running
Inverter Ducted System ODU
P2
High pressure switch protection
  • System dirty blocking
  • Damage of high voltage pressure switch
Multi-Zone (High Wall Unit)
P3
Liquid deficiency problem
High Wall (C-Series)
P3
Low refrigerant
  • Lack of the refrigerant
  • Stop valve unopened
Multi-Zone (High Wall Unit)
P4
Cooling high temperature protection of outdoor unit / Heating high temperature protection of indoor unit
  • Cooling: Poor condenser heat exchange
  • Heating: Poor evaporator heat exchange
Multi-Zone (High Wall Unit)
P5
High discharge temperature protection
  • Lack of the refrigerant
  • Stop valve unopened
  • Damaged main PCB on outdoor unit
Multi-Zone (High Wall Unit)
P6
Cooling high temperature protection of outdoor unit / Heating high temperature protection of indoor unit
  • Cooling: Poor condenser heat exchange
  • Heating: Poor evaporator heat exchange
Multi-Zone (High Wall Unit)
P7
Indoor anti-freezing protection
  • Clogged air filter of the indoor unit
  • Dust accumulation on the indoor heat exchanger
  • Defective indoor heat exchanger thermistor
  • Defective indoor unit PCB
  • Indoor fan defective
Multi-Zone (High Wall Unit)
P8
Over-current protection of the compressor drive modular
  • Excessive running current of the unit
  • Voltage drops abruptly during operation
Multi-Zone (High Wall Unit)
Timer indicator flashes 1
  • Outdoor unit overcurrent protection lock/Indoor unit overcurrent
  • IPM over-temperature protection/120AP phase loss/reverse phase protection
High Wall (LC)
Timer indicator flashes 10
  • Suction sensor fault
High Wall (LC)
Timer indicator flashes 11
  • Outdoor fan motor fault
High Wall (LC)
Timer indicator flashes 2
  • Outdoor coil sensor fault
High Wall (LC)
Timer indicator flashes 3
  • Compressor start failure or out-of-step fault
High Wall (LC)
Timer indicator flashes 4
  • Compressor discharge sensor fault
High Wall (LC)
Timer indicator flashes 5
  • Compressor housing sensor fault
  • Compressor housing temperature protection
  • High-pressure switch protection/fault
High Wall (LC)
Timer indicator flashes 6
  • Outdoor ambient sensor fault
High Wall (LC)
Timer indicator flashes 7
  • Over/under voltage protection
High Wall (LC)
Timer indicator flashes 8
  • Outdoor unit communication fault
  • Compressor over-power protection
High Wall (LC)
Timer indicator flashes 9
  • Outdoor EE fault
High Wall (LC)

Frequently Asked Questions

What is Voice Control/Hello Lisa?

"Hello Lisa" is a voice control feature that lets you turn on or control your AUX air conditioner by simply saying "Hello Lisa" followed by a command, like adjusting the temperature or mode. It works without needing a remote, app, or internet connection, making it super easy and convenient to use hands-free.

How do I enable or disable the Voice Control Function Mode (referred to as "Hello Lisa")
  1. Switch the air conditioner to Dehumidification Mode.
  2. Set the temperature to 60 degrees Fahrenheit (or 16 degrees Celsius, depending on your unit's default scale).
  3. Press the "-" (minus) button on the remote control eight times in succession.

This sequence will toggle the voice control feature on or off. If the process does not yield the expected result, consult your model's user manual or contact AUX customer support for verification.

How do I connect the Wi-Fi function?

To connect your AUX mini-split to Wi-Fi, please check the Wi-Fi setup manual included with your indoor unit. To connect your AUX mini-split to Wi-Fi:

  • Find the Wi-Fi setup manual with your indoor unit.
  • Download the "AC Freedom" app on your phone (iOS/Android).
  • Follow the app’s setup wizard to connect to a 2.4GHz Wi-Fi network.
How can I switch from 
Celsius to Fahrenheit and back?

To switch the display temperature between Celsius and Fahrenheit on your AUX air conditioner, press and hold the "+" (plus) and "-" (minus) buttons on the remote control at the same time for 3 seconds. The display should toggle between Celsius (°C) and Fahrenheit (°F). Repeat the process to switch back.

What's "SOFT" mode?

The "SOFT" mode on your AUX air conditioner runs the unit at a lower fan speed to create a quiet, gentle airflow. This mode ensures comfortable cooling with minimal noise, making it ideal for relaxing or sleeping.

What's the "I-FEEL" feature?

The "I-FEEL" feature on your AUX air conditioner uses a temperature sensor in the remote control to monitor the temperature at your location in the room. It adjusts the air conditioner's cooling or heating to maintain your desired comfort level based on where you are, rather than the unit's location.

How does "Self-Cleaning" work?

The "Self-cleaning" feature on your AUX air conditioner cleans the indoor and outdoor unit’s coil in three steps:

  • Freezing: The unit cools to freeze moisture on the coil.
  • Melting: It heats up to melt the ice, washing away dirt.
  • Drying: The fan runs to dry the coil completely.

The process takes about 30 minutes, leaving your AC clean and ready to use. Activate it using the "Self-Clean" button on your remote. Check your user manual for model-specific instructions.

How often should I clean my filter?

You should clean your AUX air conditioner's filter every 4 to 6 weeks to keep it running efficiently. If you use the AC heavily or live in a dusty area, clean it more often, like every 2 to 3 weeks

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