This rule does not apply to the use of cooking appliances, such as hobs and ovens. Unrestricted operation is possible if the extractor hood is used in recirculating mode – with activated carbon filter. Circulating-air mode: . An activated carbon filter must be fitted for this operating mode (see Filters and maintenance). The complete installation set and replacement filters can be obtained from specialist outlets. The corresponding accessory numbers can be found at the end of these operating ins