Matrix
Insert
Installation
and
Operation
Manual
42
______________________________________________________________________________
9
THE
VENTING
SYSTEM
9.1
GENERAL
The
venting
system,
made
up
of
the
chimney
and
the
liner
inside
the
chimney,
acts
as
the
engine
that
drives
your
wood
heating
system.
Even
the
best
insert
will
not
function
safely
and
efficiently
as
intended
if
it
is
not
connected
to
a
suitable
chimney
and
liner
system.
The
heat
in
the
flue
gases
that
pass
from
the
insert
into
the
chimney
is
not
waste
heat.
This
heat
is
what
the
chimney
uses
to
make
the
draft
that
draws
in
combustion
air,
keeps
smoke
inside
the
insert
and
safely
vents
exhaust
to
outside.
You
can
think
of
heat
in
the
flue
gas
as
the
fuel
the
chimney
uses
to
make
draft.
9.2
BLOCK
‐
OFF
PLATE
To
reduce
the
possibility
of
a
cold
air
draft
from
the
masonry
chimney
to
get
into
the
room
when
the
insert
in
not
working,
the
installation
of
a
sheet
metal
block
‐
off
plate
((A)
in
the
drawing
below)
is
recommended.
Once
you
have
made
the
block
‐
off
plate
to
the
proper
dimension,
cut
the
pipe
hole
slightly
larger
than
the
liner’s
diameter
and
then
install
the
liner
through
this
hole.
Set
the
Block
‐
off
plate
in
place
and
secure
with
masonry
nails
into
mortar
joints.
Finally,
seal
the
joints
between
the
plate
and
the
wall
with
high
temperature
silicone,
and
then
use
stove
‐
furnace
cement
to
seal
between
the
pipe
and
the
hole.
In
Canada,
CSA
B365
Standard
permits
the
use
of
‘’Roxul’’
type
wool
stuffed
around
the
liner
as
it
passes
through
the
throat
area
as
an
alternative
to
a
sheet
metal
Block
‐
off
plate.
However,
this
method
is
inferior
to
the
use
of
a
sheet
metal
block
‐
off
plate.
