For using the sat-nms ACU-ODU in very hot regions, it is possible to equip the sat-nms ACU-ODU with an optional temperature controlled fan. By this way it is possible to ensure the availability of the sat-nms ACU-ODU in hot ambients. ATTENTION: If the unit is equipped with an optional air ventilation, avoid contact with jets of water, rain is no problem. Through the build-in ventilator the protection class is only IP54. The thermostat for the fan is normally set to 40°C, that means the fan switches on as soon as the temperature of the cabinet raises above 40°C. We strongly recommend not to set this threshold below 40°C. The reason for this is, that in the winter the heater and the fan work against each other. In worst case the fan and the heater run parallel over a longer time. This behavior is avoided through setting the fan threshold to 40°C.