After connecting the radiator to the power socket and associating it in the app, the LED must be switched off.
If the LED is off, this is the standard condition for an operating electric radiator, associated with a system and with the correct WiFi communication.
Interacting manually with the keypad (+/-), the LEDs will change colour according to temperature range, and then switch off.
If the set point is changed in the app, the LED will remain off.