An air-conditioning system, comprising: an air-conditioning apparatus including an outdoor unit, an indoor unit, and a remote controller connected to the indoor unit, the outdoor unit and the indoor unit including devices and pipes included in a refrigerant circuit; an information terminal to be connected to the remote controller and configured to communicate with the remote controller; and a server connected to the information terminal via a network and configured to communicate with the information terminal, the outdoor unit including a first memory storing outdoor-unit identification information including a product model name and a serial number of the outdoor unit, the indoor unit including a second memory storing indoor-unit identification information including a product model name and a serial number of the indoor unit, the remote controller including a third memory configured to store the outdoor-unit identification information and the indoor-unit identification information and a display unit configured to display error information representing details of an abnormal condition when the abnormal condition occurs in the air-conditioning apparatus, the remote controller being configured to obtain the outdoor-unit identification information from the outdoor unit and to obtain the indoor-unit identification information from the indoor unit, the remote controller being configured to store the obtained outdoor-unit identification information and indoor-unit identification information into the third memory, the remote controller being configured to cause the display unit to display the stored outdoor-unit identification information and indoor-unit identification information together with the error information when an abnormal condition occurs in the air-conditioning apparatus, the information terminal being configured to obtain the outdoor-unit identification information and the indoor-unit identification information from the remote controller when the information terminal is connected to the remote controller, the information terminal being configured to transmit the obtained outdoor-unit identification information and indoor-unit identification information to the server. an air-conditioning apparatus including an outdoor unit, an indoor unit, and a remote controller connected to the indoor unit, the outdoor unit and the indoor unit including devices and pipes included in a refrigerant circuit; an information terminal to be connected to the remote controller and configured to communicate with the remote controller; and a server connected to the information terminal via a network and configured to communicate with the information terminal, the outdoor unit including a first memory storing outdoor-unit identification information including a product model name and a serial number of the outdoor unit, the indoor unit including a second memory storing indoor-unit identification information including a product model name and a serial number of the indoor unit, the remote controller including a third memory configured to store the outdoor-unit identification information and the indoor-unit identification information and a display unit configured to display error information representing details of an abnormal condition when the abnormal condition occurs in the air-conditioning apparatus, the remote controller being configured to obtain the outdoor-unit identification information from the outdoor unit and to obtain the indoor-unit identification information from the indoor unit, the remote controller being configured to store the obtained outdoor-unit identification information and indoor-unit identification information into the third memory, the remote controller being configured to cause the display unit to display the stored outdoor-unit identification information and indoor-unit identification information together with the error information when an abnormal condition occurs in the air-conditioning apparatus, the information terminal being configured to obtain the outdoor-unit identification information and the indoor-unit identification information from the remote controller when the information terminal is connected to the remote controller, the information terminal being configured to transmit the obtained outdoor-unit identification information and indoor-unit identification information to the server.