CONTINENTAL EDISON CEHC440S9 Guide D'utilisation page 39

Installing the hood
 Bent elbows and S-shaped profiles do not provide
efficient air extraction,thay are not recommended
for using.
Installation (Mode recycling)
If you do not have an exit to the
outside, the exhaust pipe is not
required,
procedures are the same as those
described in the "Installation:
Outdoor Venting" section.
When charcoal filters are used, the suction power is
decreased.
and the installation
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