La Crosse Technology WS-9031U - Manual (Page 8)

2. Insert the batteries, observing the correct
polarity (see marking).
3. Replace the battery cover on the unit.
Note:
In the event of changing batteries in any of the units,
all units need to be reset by following the setting up
procedures. This is due to a random security code
assigned by the sensor at start-up. This code must be
received and stored by the Weather Projection Station
in the first 3 minutes of power being supplied to the
sensor.
BATTERY CHANGE:
It is recommended to replace the batteries in all units on an annual basis to
ensure optimum accuracy of these units.
Please participate in the preservation of the environment.
Return used batteries to an authorized depot.
SETTING UP
The Weather Projection Station can be either batteries-operated or
powered by the provided AC-DC adapter.