The frost setting is useful when a room is not used for a prolonged period of time, by activating frost mode all other program cycles are ignored and the underfloor heating should not activate.
Frost mode is usually set at 5 Degrees C but can be altered through the function menu.
To activate the frost mode simply press and hold the arrow down button for 5 seconds, a snow flake symbol will appear at the top of the thermostat controller display showing that frost mode is active.
To cancel frost mode simply press and hold the arrow down for five seconds and the snow flake symbol will disappear.