Always use the fan oven setting for preheating to save time and electricity.After the oven has been preheated on the fan oven setting, turn the selector control knob to the oven setting you require. The oven must be preheated when cooking frozen or chilled food, and we recommend prehedting for yeast mixtures,batters,souffles and whisked sponges, otherwies preheating is not necessary as a fan oven warms up quickly. Preheat the oven until the indicator neon switches off for the first time; this will take between 5-15 minutes, depending on the temperature selected.