We
recommend
to
follow
indications
reported
under
regulations
UNI
9615
and
9731
referred
to
dimensions
of
the
chimney
(
C
)
and
however
to
avoid
using
sections
smaller
than
100
mm
.
In
the
case
where
there
are
larger
sections,
it
is
necessary
to
insert
a
steel
pipe
(A)
inside
the
masonry
one
(C),
as
shown
in
figure
2.6.
The
steel
flue
pipe
must
be
suitable
insulated
with
a
high
temperature
‐
resistant
rock
wool
or
vermiculite
material
(B).
Figure
2.6:
Example
of
extraction
flue
connection.
In
the
case
of
fire
in
the
extraction
flue
or
duct,
switch
off
the
heater
immediately
and
disconnect
it
from
the
house
mains
power
supply.