DX Free Cooling is achieved when  ambient temperatures are 5′C to 8′C (10F to 16F) below the air off or water leaving temperature set points. As the ambient temperature falls below a predetermined set point, the LPA® pumps and condenser fans continue to run while the vapour returning from the evaporators or heat exchanges by-passes the compressors allowing the compressors to cycle off during the Free Cooling cycle. Many progressive refrigeration designers choose to implement their own control strategy and customise the DX free cooling process in their equipment at design at development stage.