critical Finder

Error Code BAT OFF

Critical battery failure — chronothermostat has shut down due to critically low battery.

? What Causes This

Battery voltage has dropped below the second threshold, causing device shutdown.

Replace both pairs of batteries immediately with fresh alkaline 1.5V AA batteries.
Ensure correct polarity.
The relay is disabled in this state.

Source: page 7 of the official manual

From the manual

This error code appears in: