lf
you plan
to usean existing
chimney,
the
following
steps should be
performed:
a. Make
sure
the
chimney
hasa lining
that
is
non-
porous,
smooth, and sealed;i.e.
no holes or
openingsin the
joints
or liner.
b. Make
sure
thechimney
is
clean
and
free
of creo-
sote
build-up.
c. The
top of the chimney
shallextend
at least
3
feet above
the highest point where it passes
through
the
roof
of
a
building,
andat
least
2 feet
higher
than
any
portion
of a buildingwithin 10
feet.
d. Make sure clean-out
on chimney is air tight
when
closed.
A poorly
constructed
chimney
will be
a constant
source
of trouble
and
create
a poor
source
of heat.
The material
used
to construct
a chimney may be
any of a number of types: brick, stone, cement
blocks,
or insulated
metal.
The
construction
of a
chimney
should
be design-
ed
to retain
as much
heat
as
possible
to reduce
the
cooling of your chimney and also reduce the
creosote
andcondensation
build-up
especially
when
holding
your
fire
overnight.
The lining should be smooth, clean and not
porous,
so that it is easily
cleaned
and will not ab-
sorb moisture.
The size
of the liner
should
not be
reduced
to a size
smaller
than the stovepipe
con-
necting
the stove
to the chimney.
Because
smoke
and heat
travel
upward
in a spiral
motion,
a round
liner is most desirable.
A square -i. rectangular
shapedliner
with rounded
cornersis
more
efficient
than
onewith
sharp
corners.
Any
space
between
the
liner
and
outer
wall
should
be
DEAD
AtR
space,
not
a
circulating
air
space.
Dead
air
will retain
heat;
cir-
culating
air will chill the liner.
A chimney
may be
much
too
large
for
the stove
to operate
in
a
satisfac-
tory manner,
but
we
seldom
find
one too high.
The followingguidelines
will assist
in planning
a
stove'to-chimney
installation.
In addition
to these
guidelines,
always
consult your local building in-
spector.
1.
The
chimney
to which
the
should be clean,
free
of
tight.
stove
is
to be
attached
obstructions,
and air-
2.A
chimney
lower
than
the roof
line
will
besubject
to
a downdraft
andincreased
creosote
formation.
3.
Single
wall
pipe
will
chill
rapidly
and
cause
creo-
sote
build-up.
4.
A
single
brick
wall
chimney
wilt
also
chillrapidly,
causing
creosote.
5.A porous
cement
block
chimney
without
a
good
liner
will give
poor
drafting
and
cause
creosote
problems.
6.
A short
single
wall
metal
extension
on
the
top
of
any chimney will chill rapidly and cause
creosote.
CHIMNEY
CONSIDERATIONS
e.
Chimney
should
have
achimney
cap
to
help
pre-
vent
down
drafts.
f.
Never
connect
two stoves
on
the samelevel
to a
chimney.
g.Do not
extend
height
of chimney
with
a single
wall metal
extension.
lf you plan
to install
your
own chimney,
follow
the
generaf
examples
which follow,
in addition
to con-
sulting your local building inspector and stove
dealer. Use only Underwriters
Laboratory
Listed
Besidential
Type
Building
and
Heating
Appliance.
7.
The flue
size,
shape,
and height
of any chimney
areequally
as important
as material
used
to
con-
struct
the
chimney.
8.All
chirnneys
should
beconstructed
with
a
clean-
out
that will be
airtight
when
closed.
9.A straight
chimney
is best.
lf an
offset
chimney
is unavoidable,
it should
be
gradual,
not
sharp.
10.
The
height
of
any
chimney
should
beseveral
feet
above
the
highest
section
of the
roofline.
11.
A chimney
should
havea chimney
cap to help
prevent
downdrafts.
_ lt is imperative
that the installation
be airtight.
This
is best
accomplished
by
usingfurnace
cement
at each
pipe
joint,
and
where
the stoveis
joined
to
the
pipe,
and
where
the
pipe
enters
thechimney
flue.
The All Nighter is
designed
to operate
on an
air-
tight principle.
Any air leak
will cause
the draft
to
draw at points where least resistance
is offered,
such as at joints,
where
pipe enters
flue,
around
loose
flue
thimble,
other
flue
openings
into
chimney,
around clean-out doors in chimney, or wheie
decayed
mortar
between
bricks
has fallen
out. All
tl''gr" could permit air to leak into the chimney.
When
this occurs,
the gasses
and smoke
are not
drawn
of
f
the
stove
in
proper
amounts,
causing
them
to -build
up in the stove,
and resulting
in i,back_
puffing." All leaks must be eliminated.
Air must
enter
only
through
the
proper
entrance.
Downdrafts
in a chimney
may cause
a stove
to
smoke.
A downdraft
may
be
caused
by
air
currents
being deflected
down the chimney
by nearby
ob-
jects,
such
as trees,
buildings,
or iand
formafions.
Downdrafts
may also be caused by flue gasses
which are
chilled
too quickly
as they pass
up the
chimney.
As the gasses
cool,
they become
heavy
and
other-gasses
from
the wood
fire
have
to push
i
cof
umn
of heavy
air
ahead
of them
in
order
to escape
up.the
chimney.
This
could
result
in ,,back
puff
ing"
or back
pressure,
odors
in the house,
or poor
com-
bustion, which can be annoying.
To correct a
downdraft
caused
by
a poor
chimnby
design,
it may
benecessary
to consult
a
professional
wno
is
able
to
improve
the
chimney
design.
EVALUATING
AN
EXISTING
CHIMNEY
Page
5
