An air conditioner comprising: an outdoor unit through which refrigerant circulates; a plurality of indoor units (61 to 68) through which water circulates; a heat exchange device (100, 101) configured to connect the outdoor unit to the plurality of indoor units (61 to 68) and perform heat exchange between the refrigerant and the water, and including a plurality of ports to which the plurality of indoor units (61 to 68) are connected; and a controller configured to control flow of the water between the heat exchange device (100, 101) and the plurality of indoor units (61 to 68), wherein, to search pipes respectively connected to the plurality of ports, the controller is configured to control the flow of water such that water at a first temperature flows to some of the plurality of ports and the water at a second temperature lower than the first temperature flows to other some of the plurality of ports, characterized in that, to search pipes respectively connected to the plurality of ports, the controller is configured to control the flow of water such that water at a first temperature flows to some of the plurality of ports and the water at a second temperature lower than the first temperature flows to other some of the plurality of ports when an indoor temperature is higher than or equal to a reference temperature, and the controller is configured to control the flow of water such that the water at the first temperature flows to some of the plurality of ports and water at a third temperature of between the first temperature and the second temperature flows to other some of the plurality of ports when an indoor temperature is lower than the reference temperature. an outdoor unit through which refrigerant circulates; a plurality of indoor units (61 to 68) through which water circulates; a heat exchange device (100, 101) configured to connect the outdoor unit to the plurality of indoor units (61 to 68) and perform heat exchange between the refrigerant and the water, and including a plurality of ports to which the plurality of indoor units (61 to 68) are connected; and a controller configured to control flow of the water between the heat exchange device (100, 101) and the plurality of indoor units (61 to 68), wherein, to search pipes respectively connected to the plurality of ports, the controller is configured to control the flow of water such that water at a first temperature flows to some of the plurality of ports and the water at a second temperature lower than the first temperature flows to other some of the plurality of ports, characterized in that, to search pipes respectively connected to the plurality of ports, the controller is configured to control the flow of water such that water at a first temperature flows to some of the plurality of ports and the water at a second temperature lower than the first temperature flows to other some of the plurality of ports when an indoor temperature is higher than or equal to a reference temperature, and the controller is configured to control the flow of water such that the water at the first temperature flows to some of the plurality of ports and water at a third temperature of between the first temperature and the second temperature flows to other some of the plurality of ports when an indoor temperature is lower than the reference temperature.