An air conditioning system having a free-cooling mode. The system includes a refrigeration circuit have a compressor, a pump, an expansion device having a variable opening, and a controller. The controller selectively operates the system in the free-cooling mode by circulating the refrigerant through the refrigeration circuit via the pump. The system includes a free-cooling capacity control sequence resident on the controller. The free-cooling capacity control sequence adjusts the cooling capacity of the system at least by adjusting the variable opening based on the temperature difference between a working fluid temperature and a set point temperature.