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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 local authorities.
When the unit is used in its extractor version, a sufficiently large ventilation hole
must be provided, with dimensions that are approximately 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 recirculation mode, 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:
The ducting must be fire retardent, 120mm in diameter and the length should be
no more than:
3 metres with one 90 degree bend
2 metres with two 90 degree bends
Bends of more than 90 degrees 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.