Generation 3 - CO1500MAXWIFI3
Turn off the heater.
Turn the heater on. Immediately after this, press and hold the gear/settings button.
Release the button when "FR" appears on the display. First, you will see "CH(L)", then "CO(L)", and finally "FR". Release the button when you see "FR" in the display.
The heater will then count up and stop at 22°C. Your heater is now reset.
