Some Boretti extractor hoods have a filter replacement/cleaning indicator button [symbol: F-button]. This button will start flashing after about 40 hours of activity. If it starts flashing, it means it is time to clean the grease filters. After 120 hours of activity, the button will light up to indicate that the charcoal filters must be replaced. See "Grease filter maintenance" for more information.
To prevent the indicator button from staying on after replacing or cleaning the grease filter, reset the appliance by pressing the indicator button for 10 seconds.