Why does the PIR (754HB2/180/60) keeps activating for no reason / at random



The unit may be suffering from false activation.  Cover the sensor lens completely with a thick cloth.  This will prevent the sensor from *seeing* anything.  If the unit
now switches off after the set time duration and does not re-activate, this indicates that the problem was caused by false activation.  Ensure the unit is not positioned
so as to allow detection of cars /  people using public thoroughfares adjacent to your property.