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 Lamp | Timer Lamp | Error Code Interpretation | Meaning of Error |
| ☆ 1 time | OFF | E0 | Indoor unit EEPROM parameter error |
| ☆ 2 times | OFF | E1 | Communication malfunction between indoor and outdoor units |
| ☆ 4 times | OFF | E3 | Indoor fan speed out of control |
| ☆ 5 times | OFF | E4 | Indoor room temperature sensor (T1) malfunction |
| ☆ 6 times | OFF | E5 | Evaporator coil temperature sensor (T2) malfunction |
| ☆ 7 times | OFF | EC | Refrigerant leakage detection |
| ☆ 8 times | OFF | EE | Water-level alarm malfunction |
| ☆ 1 time | SOLID | F0 | Current overload protection |
| ☆ 2 times | SOLID | F1 | Outdoor ambient temperature sensor (T4) malfunction |
| ☆ 3 times | SOLID | F2 | Condenser coil temperature sensor (T3) malfunction |
| ☆ 4 times | SOLID | F3 | Compressor discharge temperature sensor (T5) malfunction |
| ☆ 5 times | SOLID | F4 | Outdoor unit EEPROM parameter error |
| ☆ 6 times | SOLID | F5 | Outdoor fan speed has been out of control |
| ☆ 7 times | SOLID | F6 | Indoor coil outlet pipe sensor (Located on outdoor unit low pressure valve) |
| ☆ 8 times | SOLID | F7 | Communication malfunction between Cassette optional lift panel and the unit |
| ☆ 9 times | SOLID | F8 | Cassette optional lift panel malfunction |
| ☆ 10 times | SOLID | F9 | Cassette optional lift panel not closed |
| ☆ 1 time | FLASHING | P0 | Inverter module (IPM) malfunction |
| ☆ 2 times | FLASHING | P1 | Over-voltage or under-voltage protection |
| ☆ 3 times | FLASHING | P2 | Compressor top high temperature protection (OLP) |
| ☆ 4 times | FLASHING | P3 | Low ambient temperature cut off in heating |
| ☆ 5 times | FLASHING | P4 | Compressor drive malfunction |
| ☆ 6 times | FLASHING | P5 | Indoor units mode conflict |
| ☆ 7 times | FLASHING | P6 | Low pressure protection |
| ☆ 8 times | FLASHING | P7 | Outdoor 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.