Question about Netatmo Wireless radiator thermostat set

If the battery is flat, is it possible to adjust the temperature by hand by turning the thermostat? Thank you

as in the picture, I received 2 pieces plus the "central unit". I then added a third thermostat.
The "central" i.e. the square box communicates with the thermostats via 868 MHz radio, and with the WLAN on 2.4 GHz.
Attention: The system does not like short (seconds) power interruptions. However, the central unit can also be supplied directly with 5 V via USB.
via USB. A micro-USB plug is well hidden under the 230 V connector.