Multi-unit air conditioner and method for controlling the same

A multi-unit air conditioner comprising:

• a plurality of indoor units;
• an outdoor unit connected with the indoor units, the outdoor unit comprising a microcomputer for controlling an operation of the outdoor unit, and enabling the outdoor unit to communicate with the indoor units;
• an electronic expansion valve arranged in a refrigerant line through which a refrigerant from the outdoor unit is introduced into the indoor units;
• first intermittent valves arranged in a refrigerant line through which the refrigerant is introduced into the indoor units;
• second intermittent valves arranged in a refrigerant line through which the refrigerant from the indoor units is discharged into the outdoor unit;
• and
• at least one controller for determining whether each of the indoor units is in a normal operation state or in a non-operation state, and controlling an operation of a distributor in accordance with the result of the determination, the at least one controller being arranged in at least one of the outdoor unit and a distributor, respectively.

A method for controlling a multi-unit air conditioner including an outdoor unit and a plurality of indoor units, comprising the steps of:

• checking a communication state established between the outdoor unit and each of the indoor units;
• determining whether or not there is a powered-off one of the indoor units under a condition in which a communication state is established between the outdoor unit and each of the indoor units;
• recovering a refrigerant from the powered-off indoor unit;
• and
• cutting off the refrigerant supplied to the powered-off indoor unit.