Air conditioning system and method for controlling air conditioning system

A method for controlling an air conditioning system including an outdoor unit, an indoor heat exchanger connected to the outdoor unit and including a temperature sensor, an auxiliary heat source arranged as an auxiliary to the outdoor unit and operated by an energy source different from an energy source of the outdoor unit, and a communicator connected to the outdoor unit, the indoor heat exchanger, and the auxiliary heat source, wherein the communicator connects a first side of the air conditioning system including a thermostat with a second side of the air conditioning system including the indoor heat exchanger and the auxiliary heat source, and wherein the outdoor unit and the auxiliary heat source are connected to the communicator using different communication schemes, the method comprising:

• receiving a heating signal when a heating operation is started;
• determining one of a first heating using the outdoor unit or a second heating using the auxiliary heat source, based on an outdoor temperature;
• transmitting an operation signal to the outdoor unit when the first heating is determined;
• determining whether the outdoor unit has failed and switching to the second heating when it is determined that the outdoor unit has failed;
• transmitting an operation signal to the auxiliary heat source when the second heating is determined;
• and determining whether the auxiliary heat source has failed and switching to the first heating when it is determined that the auxiliary heat source has failed, wherein the temperature sensor is a duct temperature sensor arranged on a duct of the indoor heat exchanger.

An air conditioning system, comprising:

• an outdoor unit;
• an indoor heat exchanger connected to the outdoor unit, the indoor heat exchanger comprising a temperature sensor;
• a gas furnace operated by an energy source different from an energy source of the outdoor unit;
• a thermostat configured to control a temperature of an installation space supplied with cold air or warm air by the outdoor unit and the gas furnace;
• and
• a communicator that connects a first side of the air conditioning system including the thermostat with a second side of the air conditioning system including the indoor heat exchanger and the gas furnace, the communicator comprising:
• an input unit connected to the thermostat;
• a first output unit connected to the gas furnace;
• a second output unit connected to the outdoor unit;
• and
• a controller configured to process signals between the input unit, the first output unit, and the second output unit, wherein the controller monitors an operating state of at least one of the outdoor unit or the gas furnace using the temperature sensor, and wherein the controller switches an operation to the gas furnace when an error is maintained in the outdoor unit for a predetermined time or longer, or when a temperature detected by the temperature sensor is maintained to be less than or equal to a first temperature for a predetermined time, wherein the outdoor unit and the gas furnace are connected to the communicator using different communication schemes.