If you have more than one tado° device installed in the same room in the app, they synchronize their settings (e.g. the temperature set on a device).
However, sometimes changes can’t be transmitted immediately. In this case, the synchronizing symbol will turn on as follows:
two arrows on the Smart Thermostat or Wireless Temperature Sensor,
a rotating circle on the Smart Radiator Thermostat, and
a spanner on the Smart Radiator Thermostat Basic.
While the symbol is on, the device keeps sending the changes to other devices in the same room until they are received. Any further change on the same or a different device during that time overrides the previous one.
The most common reason for non-transmitted changes is a temporary loss of radio link between the Internet Bridge and any other device. This is usually resolved by itself within a few minutes. However, if the interruption persists for more than 30 minutes, restart the devices.