HC represents a fault in the fan drive current detection circuit.By viewing the fault code on the double-eight digital tube of the outdoor unit main control board, if HC is displayed on the digital tube, it can be judged that the fan drive current detection circuit is faulty. The possible cause is that the fan drive board is abnormal.According to the maintenance manual, the indoor unit displays HC as PFC overcurrent protection, and the outdoor unit yellow indicator blinks 14 times. When the compressor starts, the circuit current is detected, and if it exceeds the protection value, it protects the shutdown to prevent excessive current from damaging PFC circuit components.Possible failure point: sudden change of power grid voltage; Reactor, PFC inductance short circuit; The external controller is faulty.Fault process: PFC overcurrent protection, detect whether the power grid voltage changes suddenly, if yes, it is normal protection; If not, then determine whether the reactor, PFC inductance short circuit, if yes, you need to replace the reactor, PFC inductance, if not, you need to replace the external electrical box.