21
Prior to installation
❑ Flat ducts must have an internal cross-
section that equates to that of round
pipes.
There should be no sharp bends.
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:
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.
ṇ The manufacturer of the extractor
hoods accepts no liability for complaints
which can be attributed to the design
and layout of the pipework.
❑ If pipes have different diameters:
Insert sealing strip.
❑ For exhaust-air mode, ensure that
there is an adequate supply of fresh air.
Round pipes
Internal diameter
Flat ducts
Cross-section
l
100 mm
179 cm
2
l
120 mm
113 cm
2
l
150 mm
177 cm
2
Air connector l 150 mm
Mount the pipe
directly onto the air
outlet on the hood.
Attach the reducing
connector (enclosed
or available from
specialist retailer)
to the air pipe and
then attach to the
exhaust-air duct.
Air connector l 120 mm
Mount the pipe
directly onto the air
outlet on the hood.
Attach the reducing
connector (enclosed
or available from
specialist retailer)
to the air pipe and
then attach to the
exhaust-air duct.
❑ Snap the one-way
flap into the air pipe.
ṇ The two lightly
sprung flaps must
be able to move
upwards.
