The national Standard on fuel-burning systems specifies a maximum depression of 0.04 mbar in such rooms.

The air outlet must not be connected to chimney flues or combustion gas ducts. The air outlet must under no circumstances be connected to ventilation ducts for rooms in which fuel-burning appliances are installed.

The air outlet installation must comply with the regulations laid down by the relevant authorities.

When the unit is used in its extractor version, a sufficiently large ventilation hole must be provided, with dimensions that are approxi- mately the same as the outlet hole.

National and regional building regulations impose a number of restrictions on using hoods and fuel-burning appliances connected to a chimney, such as coal or oil room-heaters and gas fires, in the same room.

Hoods can only be used safely with appliances connected to a chimney if the room and/or flat (air/environment combination) is ventilated from outside using a suitable ventilation hole approximately 500-600 cm2 large to avoid the possibility of a depression being created during operation of the hood.

If you have any doubts, contact the relevant controlling authority or building inspector’s office.

Since the rule for rooms with fuel burning appliances is “outlet hole of the same size as the ventilation hole”, a hole of 500-600 cm2, which is to say a larger hole, could reduce the performance of the extractor hood.

If the hood is used in its filtering function, it will operate simply and safely in the above conditions without the need for any of the aforementioned measures.

When the hood is used in its extractor function, the following rules must be followed to obtain optimal operation:

short and straight outlet hose

keep bends in outlet hose to a minimum

never install the hoses with an acute angle, they must always follow a gentle curve.

keep the hose as large as possible (preferably the same diameter as the outlet hole).

the length should be no more than:

3 metres with one 90° bend

2 metres with two 90° bends

Bends of more than 90° will reduce the efficiency of the hood and reduce the airflow.

Failure to observe these basic instructions will drastically reduce the performance and increase the noise levels of the extractor hood.

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Electrolux HU 3360, HU 4360, DU 3160, DU 3150 installation instructions