Siemens D 8622 N0 Operating And Installation Instructions page 21

Prior to installation
For operating in exhaust-air mode, a
one-way flap should be mounted inside the
extractor hood unless there is already one
fitted in the outlet duct or wall ventilation
box.
If no one-way flap was enclosed with the
hood, it can be obtained from a specialist
retailer.
Installing the one-way flap:
Snap the one-way flap into the air pipe.
The two lightly sprung flaps must be
able to move upwards.
For optimum extractor hood efficiency:
Short, smooth air exhaust pipe.
As few bends in the pipe as possible.
Diameter of pipe to be as large as
possible and no tight bends in pipe.
If long, rough exhaust-air pipes,
many pipe bends or smaller pipe
diameters are used, the air extraction
rate will no longer be at an optimum
level and there will be an increase in
noise.
The manufacturer of the
extractor hoods accepts no liability
for complaints which can be
attributed to the design and layout of
the pipework.
Round pipes:
We recommend
Internal diameter: 125 mm (at least
100 mm).
Flat ducts must have an internal cross-
section that equates to that of round
pipes.
There should be no sharp bends.
l 100 mm approx. 178 cm
l 125 mm approx. 113 cm
If pipes have different diameters:
Insert sealing strip.
For exhaust-air mode, ensure that
there is an adequate supply of fresh air.
Connecting a l 125 mm exhaust-air
pipe:
Mount the pipe directly onto the air
outlet on the hood.
Connecting a l 100 mm exhaust-air
pipe:
Attach the reducing connector
(enclosed or available from specialist
retailer) to the air pipe and then attach
to the exhaust-air duct.
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