| E1 | Communication fault between indoor and outdoor units | Damaged communication wiring, PCB fault, or voltage issue | Professional inspection of inter-unit wiring and control boards |
| E2 | Indoor unit room temperature sensor fault | Damaged or disconnected indoor thermistor | Sensor resistance test and replacement by certified technician |
| E6 | Outdoor ambient temperature sensor fault | Corroded or physically damaged outdoor sensor | Outdoor sensor replacement and full system retest |
| C4 | Pipe temperature sensor fault on indoor unit | Faulty pipe thermistor affecting refrigerant monitoring | Thermistor replacement and refrigerant pressure verification |
| E4 | Condensate drain pump fault | Blocked drain line, pump motor failure, or float switch fault | Drain system inspection, clearance, and pump test |
| F1 | Refrigerant leak detection alert | Low refrigerant pressure detected by system pressure sensor | Leak location, repair, and refrigerant recharge to specification |
| P1 | High pressure protection on outdoor unit | Blocked condenser, refrigerant overcharge, or outdoor fan failure | Condenser inspection, pressure measurement, and fan motor test |
| P2 | Low pressure protection fault | Refrigerant undercharge or expansion valve restriction | Refrigerant level verification and pressure restoration |
| H6 | Outdoor fan motor protection fault | Fan motor overload, bearing failure, or housing obstruction | Outdoor fan motor inspection, amperage test, and replacement if required |
| ZC | Zone controller communication fault | Wiring fault between zone controller and central unit | Zone controller wiring inspection and controller function test |