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LCAC (FYB/CYB/UYB/RYB) Error Code InterpretationUpdated 18 days ago

Interpreting Light Commercial AC (LCAC) Codes When There is no LED Display

Some systems do not possess an onboard LED readout on the indoor unit. Instead, there are various light indicators to convey system operation.

Whenever there's an error code, these light indicators will flash in a certain sequence to convey the type of error the system is experiencing. The sequence can be interpreted by the user using the following table:

Operation LampTimer LampError Code InterpretationMeaning of Error
☆ 1 time
OFFE0Indoor unit EEPROM parameter error
☆ 2 times
OFFE1Communication malfunction between indoor and outdoor units
☆ 4 times
OFF
E3Indoor fan speed out of control
☆ 5 times
OFF
E4Indoor room temperature sensor (T1) malfunction
☆ 6 times
OFF
E5Evaporator coil temperature sensor (T2) malfunction
☆ 7 times
OFF
ECRefrigerant leakage detection
☆ 8 times
OFF
EEWater-level alarm malfunction
☆ 1 time
SOLIDF0Current overload protection
☆ 2 times
SOLID
F1Outdoor ambient temperature sensor (T4) malfunction
☆ 3 times
SOLID
F2Condenser coil temperature sensor (T3) malfunction
☆ 4 times
SOLID
F3Compressor discharge temperature sensor (T5) malfunction
☆ 5 times
SOLID
F4Outdoor unit EEPROM parameter error
☆ 6 times
SOLID
F5Outdoor fan speed has been out of control
☆ 7 times
SOLID
F6Indoor coil outlet pipe sensor (Located on outdoor unit low pressure valve)
☆ 8 times
SOLID
F7Communication malfunction between Cassette optional lift panel and the unit
☆ 9 times
SOLID
F8Cassette optional lift panel malfunction
☆ 10 times
SOLID
F9Cassette optional lift panel not closed
☆ 1 time
FLASHINGP0Inverter module (IPM) malfunction
☆ 2 times
FLASHING
P1Over-voltage or under-voltage protection
☆ 3 times
FLASHING
P2Compressor top high temperature protection (OLP)
☆ 4 times
FLASHING
P3Low ambient temperature cut off in heating
☆ 5 times
FLASHING
P4Compressor drive malfunction
☆ 6 times
FLASHING
P5Indoor units mode conflict
☆ 7 times
FLASHING
P6Low pressure protection
☆ 8 times
FLASHING
P7Outdoor IPM temperature sensor error

Below is an example of a CYB air handler flashing an error code pattern. 


As we can observe, the sequence is:

  • Timer Light -> FLASHING ★
  • Operation Light -> 7x Flashes ★

Therefore, the code is P6 for Low Pressure (Low Refrigerant/Leak) Detection Protection.


Here is another example of an error code for CYB systems:

As we can observe, the sequence is:

  • Timer Light -> FLASHING ★
  • Operation Light -> 6x Flashes ★

Therefore, the code is P5 for Indoor Units Mode Conflict. This usually occurs on a multi-zone setup where one indoor unit is calling for heat and another is calling for cooling. On multi-split systems, all indoor units must be working in the same mode of either ALL COOL or ALL HEAT. The code can be eliminated by changing all units to the same mode, or turning the conflicting unit off. Using AUTO mode can sometimes result in this error as well.

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