Page 10
Ceiling penetration
clearances
5.
Flue
&
chimney
requirements
cont...
Existing
chimneys
should
be
inspected
and
cleaned
by
a
qualified
professional
prior
to
installation.
The
chimney
must
not
have
cracks,
loose
mortar
or
other
signs
of
deterioration
and
blockage.
Jetmaster
recommends
a
certified
professional
or
a
technician,
under
the
direction
of
a
certified
professional.
Single
skin
flue
(stainless
steel)
must
be
completely
enclosed
with
single
skin
brickwork,
concrete,
or
autoclaved
aerated
concrete
block.
A
chimney
plate
will
be
used
to
weather
seal
the
chimney.
Twin
skin
flues
(stainless
steel
inner,
and
galvanised
outer)
can
either
be
left
exposed
or
enclosed
with
stud
walls
and
sheet
plaster
or
timber.
A
minimum
of
50mm
clearance
must
be
maintained
between
the
outer
flue
and
any
combustibles
within
the
chase
or
ceiling
cavity.
(Fig
5.1)
Position
an
active
starter
flue
with
two
female
ends
to
gather
to
allow
second
length
to
have
crimp
facing
down.
(Fig
5.2)
Glass
tape
may
be
required
to
ensure
a
snug
fit.
The
outer
flue
is
then
installed
outside
active
flue
with
crimp
facing
up
to
ensure
water
penetration
on
flue
above
roof
runs
out.
Rivet
active
flues
together
at
crimped
joins.
Fix
outer
non-active
flues
to
active
inner
flues
use
3
x
25mm
self-
tapping
screws
through
outer
flue
at
bottom
at
each
join
and
on
top
at
each
join.
As
an
alternative,
rivet
4
x
25mm
conduit
saddles
at
each
join
top
and
bottom.
Cowl
For
solid
fuel
applications
only,
a
double cone
cowl
will
assist
in
preventing
the
effects
of
downdraft.
(Fig
5.3)
Other
solid
fuel
cowls
may
be
desired
to
achieve
a
visual
design
and
such
cowls
can
be
used
but
must
not
restrict
airflow
from
the
flue
pipe
casings.
For
gas
applications
an
AGA
approved
cowl
must
be
used.
Fig 5.2
Fig 5.3
Fig 5.1
Combustible ceiling
Combustible ceiling
Support angles
50mm gap from
Combustible materials
Outer Gal casing
Active stainless steel
Active stainless steel
Outer Gal casing
Crimped end down
From second length
Gather
Trim the crimp off first
length stainless pipe
Double cone
cowl