Renewing the Desiccant
The inside of the instrument must be kept dry to maintain good electrical insulation and to
prevent moisture from condensing on the optical parts of the instrument. Such condensation
makes all the readings false. It’s strongly recommend that external drier units be used with all
instruments. These units should slowly pump dry, clean air into the instrument. Being external,
the desiccant can easily be monitored, and changed as needed without opening the instrument.
Minimizing the opening and closing of the instrument, minimizes the dust entering the instrument.
Also, the clean air that is pumped in, leaks out thus keeping dust from entering. An indicator-type
silica gel should be used which changes colour when it becomes damp. An example is the type