Patent ID: 8302418

Claim:
An air conditioning system comprising: an outdoor unit and an indoor unit connected to each other through common power supply lines, wherein the outdoor unit includes a first communication circuit configured to perform communication by using, as communication lines, at least one of the power supply lines and at least one signal line independent of the power supply lines, and the indoor unit includes: a pair of terminals to which the communication lines from the first communication circuit are connected; a second communication circuit that is connected to the pair of terminals, and which communicates with the first communication circuit over the at least one power supply line and the at least one signal line independent of the power supply lines; a switch configured to set the first communication circuit and the second communication circuit to a connection state or a disconnection state; a detection circuit configured to detect a voltage appearing between the pair of terminals, and to detect faulty wiring between the at least one power supply line and the at least one signal line connected between the first communication circuit and the second communication circuit on the basis of a detected voltage; a controller configured to control the switch to set the first communication circuit and the second communication circuit to the disconnection state when an occurrence of faulty wiring is estimated, the occurrence of faulty wiring being estimated when the voltage detected by the detection circuit is equal to or more than a predetermined threshold value, and the controller further configured to control the switch to otherwise set the first communication circuit and the second communication circuit to the connection state; and a judging circuit configured to judge whether communication can be performed between the outdoor unit and the indoor unit when the controller controls the switch to set the first and second communication circuits to the connection state, and detecting faulty wiring between the at least one power supply line and the at least one signal line connected between the first communication circuit and the second communication circuit on the basis of a communication result between the first communication circuit and the second communication circuit.