The code indication changes as shown below, and notifies with a long beep. 00: Normal A1: Indoor Pcb Error A3: Drain Pump Abnormal A5: Antifreeze (Cooling)/Heat Exchanger Overheat (Heating) A6: Indoor Fan Motor Abnormalah Electrical Air Cleaner Abnormal C4: Indoor Heat Exchanger (1) Thermistor Short/open C5: Indoor Heat Exchanger (2) Thermistor Short/open C7: Louver Limit