Fakro ZRD Rain Sensor The detector in cooperation with the ZWMP weather module provides the facility of automatically closing the windows when equipped with motors compatible with the Z-Wave system in case of rainfall. This sensor can also be used in smoke ventilation systems. The signal from the sensor is taken into account only when the smoke ventilation window is opened for ventilation. In case of emergency opening, a signal from the rain sensor is ignored. The sensor is unaffected by such conditions such as mist, dew or condensation etc. The sensor is intended for installation in the open sections of the roof directly exposed to weather conditions.