Miele TX2070 Operating And Installation Instructions page 9

Warning and Safety instructions
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 cooker hood and the heater are in operation simultan-
eously, an underpressure in the room of 0.04 mbar (4 pa) is the
maximum permissible.
Ventilation can be maintained by air inlets which cannot be
blocked, in windows, doors or outside wall vents, or by other tech-
nical measures, such as ensuring that the cooker hood 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.
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 (registered with an official gas safety body
in accordance with national safety regulations, GasSafe in the UK)
must be sought.
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