Patent ID: 8230691

Claim:
A method of cleaning an air conditioner, the method comprising: a nitrogen charging step of charging a refrigeration cycle with nitrogen gas; a nitrogen venting step of discharging a charging target with which the refrigeration cycle is charged after the nitrogen charging step to the atmosphere; a nitrogen repeating step of repeating a nitrogen unit operation at least one time, the nitrogen unit operation including the nitrogen charging step and the nitrogen venting step; a carbon dioxide charging step of charging the refrigeration cycle with carbon dioxide after finishing the nitrogen repeating step; a carbon dioxide venting step of discharging the charging target with which the refrigeration cycle is charged after the carbon dioxide charging step to the atmosphere; a carbon dioxide repeating step of repeating a carbon dioxide unit operation at least one time, the carbon dioxide unit operation including the carbon dioxide charging step and the carbon dioxide venting step; and utilizing carbon dioxide as a working refrigerant after finishing the carbon dioxide repeating step; wherein a relationship between a number of times that the nitrogen unit operation is repeated and at least one of a temperature of the nitrogen with which the refrigeration cycle is charged and a pressure inside the refrigeration cycle when stopping charging is a substantially inverse proportional relationship.