Failure diagnosis system configured to diagnose a state of an air-conditioning apparatus having a refrigerant circuit

A failure diagnosis system configured to diagnose a state of an air-conditioning apparatus having a refrigerant circuit in which refrigerant circulates, the failure diagnosis system comprising:

• a state detection sensor configured to detect a state of the refrigerant in the refrigerant circuit as state data;
• a controller configured to control an actuator of the air-conditioning apparatus;
• a processor, and
• the processor being configured to perform normal-operation abnormality diagnosis determining presence or absence of abnormality of the air-conditioning apparatus by using
• the state data, and
• control data indicating a content of control by the controller during a normal operation of the air-conditioning apparatus,
• the processor being configured to,
• when determining that abnormality is present in the air-conditioning apparatus,
• change a control value of the actuator of the air-conditioning apparatus,
• acquire the state data and the control data, and
• perform abnormality-cause identification diagnosis identifying a cause of an abnormality of the air-conditioning apparatus by using
• the state data and the control data that are acquired before the change of the control value of the actuator, and
• the state data and the control data that are acquired after the change of the control value of the actuator,
• wherein the processor is configured to
• obtain refrigerant state information, indicating the state of the refrigerant at a specific location of the refrigerant circuit, by using the state data and the control data in the normal-operation abnormality diagnosis, and
• obtain the refrigerant state information by using the state data and the control data after the change of the control value of the actuator and compare the obtained refrigerant state information with the refrigerant state information obtained in the normal-operation abnormality diagnosis to identify the cause of the abnormality in the air-conditioning apparatus in the abnormality-cause identification diagnosis, further comprising
• a communication device serving as an interface when the processor communicates with an external device,
• wherein the processor is configured to cause an information terminal connected via the communication device to display the refrigerant state information obtained in the normal-operation abnormality diagnosis and the refrigerant state information acquired after the change of the control value of the actuator.