An internal backup battery is required for the controller to operate correctly.

If the battery is not installed, or if it has failed and needs replacing, an error message  will be displayed when the controller is powered on.

After installing a new battery:

1. Power on the controller
2. The error message may still be displayed
3. Power off the controller
4. Wait 5–10 seconds
5. Power the controller back on

The error message will be cleared once the battery is detected by the controller.