Miele SmartLine Operating And Installation Instructions page 11

Using at the same time as other heating appliances that depend on the air
from the room
 Danger of toxic fumes!
Great care should be taken when using the downdraft extractor in
the same room or the same area of the house as another heating
appliance that depends on the air from the room.
Such heating appliances draw in air from the room and duct
exhaust gases out through a chimney or extraction ducting. They
include gas, oil, wood and coal-fired boilers and heaters,
continuous flow or other water heaters, gas hobs and ovens.
The downdraft extractor draws in air from the kitchen and from
neighbouring rooms. This applies to the following modes of
operation:
- extraction mode,
- recirculation mode with a recirculation box installed outside the
room.
If there is insufficient air, an underpressure will occur. The heating
appliance may be starved of oxygen. This impairs combustion.
Harmful gases could be drawn from the chimney or extraction
ducting back into the room.
This could have potentially fatal consequences!
Warning and Safety instructions
11