Patent ID: 7600389

Claim:
A multi-unit air conditioner comprising: a plurality of indoor units each comprising a power controller adapted to independently power on or off an associated one of the 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; at least one controller for determining whether each of the indoor units is in an operation state or in a non-operation state, and controlling an operation of a distributor in accordance with the result of the determination; a refrigerant line connected to the outdoor unit; branch refrigerant lines connected between the refrigerant line and the plurality of indoor units; sub electronic expansion valves respectively arranged in the branch refrigerant lines; and a main electronic expansion valve arranged in the refrigerant line, and a plurality of first valves provided in the respective branch refrigerant lines, wherein the at least one controller controls at least one of the plurality of first valves to be closed when a corresponding indoor unit is determined to be in the non-operation state, and controls the corresponding indoor unit to be operated for a predetermined period of time after the closing of at least one of the plurality of first valves.