Miele DA 3360 Operating And Installation Instructions page 7

There must be adequate ventilation of
the room when the rangehood is used
at the same time as appliances burning
gas or other fuels.
In order to ensure safe operation, and
to prevent gases given off by the
heating appliances from being drawn
back into the room when the rangehood
and the heater are in operation
simultaneously, an underpressure of
0.04 mbar (4 pa) is the maximum
permissible in the room.
Ventilation can be maintained by air
inlets which must not be blocked, in
windows, doors and outside wall vents,
or by other technical measures, such
as ensuring that the rangehood can
only be switched on when the heating
appliance is switched off or vice versa.
A ventilation brick alone is not generally
sufficient to ensure safe ventilation.
Warning and Safety instructions
,
The overall ventilation condition
of the dwelling must be taken into
account. If in any doubt, the advice
of a competent builder or, for gas, a
qualified gas fitter must be sought.
If the rangehood is being operated in
recirculation mode, the above
restrictions do not apply.
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