First, run the refrigeration mode to allow the evaporator to condense water droplets and remove dust from the evaporator; run the heating mode again to evaporate the water on the evaporator and prevent the growth of bacteria. After sterilization, control the speed of the internal and external fans and the frequency of the compressor to make the condenser frost and remove dust from the condenser. Finally, run the air supply mode and blow off the excess heat on the evaporator before exiting the automatic cleaning function.