Abus GRWM30500 Manuel Utilisateur page 37

Weak batteries
If the battery charge of the detector falls below a certain value, the detector
signals this with an acoustic warning tone (every 40 seconds).
If this warning signal sounds, replace the detector immediately. The detector
battery is built in and cannot be exchanged.
From the time of the first battery warning signal, the detector is
still operable and completely functional for at least 30 more days.
Self-test with automatic error message
The smoke alarm device periodically runs a self-test.
If the trigger sensitivity of the detector falls below the required minimum
threshold (e.g. excess contamination of the smoke measurement chamber),
the detector beeps once every 40 seconds.
If the error message does not clear after the detector has been
cleaned, the detector must be replaced immediately (see chapter
'Care and maintenance').
Displays and functions
37