La Crosse Technology Weather Station Instruction Manual page 6

INSTALL AND REPLACE BATTERIES IN THE THERMO-HYGRO TRANSMITTER
The Thermo-hygro transmitter uses 2 x AA, IEC LR6, 1.5V battery. To install and replace the batteries, please follow the steps
below:
1. Remove the battery compartment cover.
2. Insert the batteries, observing the correct polarity (see marking).
3. Replace the battery compartment 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
because a random security code is assigned by the transmitter at start-up and this code must be received and stored by the
Weather station in the first 3 minutes of power being supplied to it
24