Override Buttons

Your Time switch has two override buttons for each of the two zones: -

1.+1 HR If pressed when the unit is in AUTO or ALL DAY mode the heating will come on instantly for one hour. If it is pressed whilst the heating is already on, it will stay on for one extra hour. 

2.MAN If pressed when the unit is in AUTO or ALL DAY mode and whilst the heating is already on, the heating will turn off and remain off until it is next due to come on again. If pressed whilst the heating is off, the heating will come on until it is next due to go off again.