To set a program, press and hold the PROG button for 3 seconds.
Press PROG 3 times to skip through setting the time (stop when P1 appears on the screen). The screen will display P100, indicating that you are setting the time for Monday (P1) at midnight (00).
Press and hold the PROG button for 3 seconds to enter the programming mode for Monday.
Press (+) and (-) to select the hour and press (checkmark) button to select the corresponding mode.
2 white rectangles indicate Comfort mode, 1 white rectangle indicates Eco Mode, and no white rectangles indicates Anti-Freeze Mode.
https://www.electricradiatorsdirect.co.uk/manuals/reina/Reina-Maia-Manual.pdf