An air conditioning system may include an outdoor unit including a compressor; at least one distributor connected to the outdoor unit and including a condenser and an evaporator that exchange heat between refrigerant and water; a plurality of heating pipes in communication with the condenser; a plurality of cooling pipes in communication with the evaporator; a plurality of fan coil units connected to the plurality of heating pipes or the plurality of cooling pipes; and a controller configured to perform a heating pipe search operation for matching a portion of the plurality of fan coil units with the plurality of heating pipes, and a cooling pipe search operation for matching another portion of the plurality of fan coil units with the plurality of cooling pipes, in parallel.