The batteries should be changed annually at a minimum, but they may require changing up to every six months if there is heavy usage or if the signal strength is low.  

Installing or replacing batteries

Approximately one month prior to the end of the battery life, a Low Battery Trouble signal is indicated at the PIM400 (located in the control panel enclosure).

1. Remove the battery cover.

2. Remove the battery bracket. Do not allow the battery pack to hang from the wires.

3. Install the new batteries (install only new AA Alkaline batteries). Make sure the batteries are installed in the correct orientation.

4. Reinstall the battery pack and battery bracket.

5. Reinstall the battery cover, making sure the connector is above the battery pack.