Installation guide
For
Best
Performance:
m
Use
26-gauge
minimum
galvanized
or
25-gauge
minimum
aluminum
metal
vent.
Poor
quality
pipe
fittings
can
reduce
airflow.
Flexible
metal
vent
is
not
recommended.
NOTE:
Local
codes
may
require
a
heavier
gauge
material.
m
Metal
duct
may
be
reduced
to
30-gauge
galvanized
steel
or
26-gauge
aluminized
steel
if
allowed
by
local
codes.
This
reduction
is
based
on
information
in
the
International
Residential
Codes
Section
M1601.1
(2006
edition).
Do
not
install
2
elbows
together.
Use
no
more
than
three
90°
elbows.
If
an
elbow
is
used,
install
it
as
far
away
as
possible
from
the
hood’s
vent
motor
exhaust
opening.
m
Make
sure
there
is
a
minimum
of
18"
(45.7
cm)
of
straight
vent
between
the
elbows
if
more
than
one
elbow
is
used.
m
Elbows
too
close
together
can
cause
excess
turbulence
that
reduces
airflow.
m
Donotuse
a5"
(12.7
cm)
elbow
in
a6"
(15.2
cm)
or
3%"
x
10"
(8.3
x
25.4
cm)
system.
m
Do
not
reduce
to
a
5"
(12.7
cm)
system
after
using
6"
(15.2
cm)
or
3%"
x
10°
(8.3
x
25.4
cm)
fittings.
gm
Avoid
forming
handmade
crimps.
Handmade
crimps
may
restrict
airflow.
m
Use
a
vent
cap
for
proper
performance.
If
an
alternate
wall
or
roof
cap
is
used,
be
certain
the
cap
size
is
not
reduced
and
that
it
has
a
back
draft
damper.
Use
vent
clamps
to
seal
all
joints
in
the
vent
system.
Use
caulking
to
seal
exterior
wall
or
roof
opening
around
the
cap.
The
length
of
vent
system
and
number
of
elbows
should
be
kept
to
a
minimum
to
provide
efficient
performance.
The
maximum
equivalent
length
of
the
vent
system
is
60
ft
(18.3
m).
For
altitudes
above
4,500
ft
(1272
m),
reduce
recommended
vent
run
by
20%
for
best
performance.
Cold
Weather
Installations
An
additional
back
draft
damper
should
be
installed
to
minimize
backward
cold
air
flow
and
a
thermal
break
installed
to
minimize
conduction
of
outside
temperatures
as
part
of
the
vent
system.
The
damper
should
be
on
the
cold
air
side
of
the
thermal
break.
Makeup
Air
Local
building
codes
may
require
the
use
of
makeup
air
systems
when
using
ventilation
systems
greater
than
specified
CFM
of
air
movement.
The
specified
CFM
varies
from
locale
to
locale.
Consult
your
HVAC
professional
for
specific
requirements
in
your
area.
Venting
Methods
Common
venting
methods
are
shown
for
a
counter-mounted
downdraft
cooktop.
The
cooktop
may
be
vented
through
the
wall
or
floor.
Option
1
-
Roof
Venting
Option
2
-
Wall
Venting
«B
I J
B
Ir
T
A
A
@
A.
Roof
cap
A.
6"
(15.2
cm)
round
wall
venting
B.6"
(15.2
cm)
round
roofventing
—_B.
Wall
cap
Option
3
-
Venting
Between
Floor
Joist
Option
4
-
Venting
behind
Cabinet
Kick
Plate
\
(
a
/
3x
25.4cm)
©
B
A
B
A.
Wall
cap
A.
Wall
cap
B.
6"
(15.2
cm)
round
wall
venting
—_B.
6"
(15.2
cm)
round
wall
venting
Concrete
Slab
Installations
-
Exhaust
Through
Window
Well
A.
Wall
cap
B.
12"
(30.5
cm)
minimum
C.
Concrete
slab
D.
6"
(15.2
cm)
round
PVC
sewer
pipe
E.5"
to
6"
(12.7
cm
to
15.2
cm)
transition
F.
6"
(15.2
cm)
round
metal
duct
G. 6"
(15.2
cm)
round
PVC
coupling
H.
6"
(15.2
cm)
round
PVC
sewer
pipe
1.6"
(15.2
cm)
round
90°
PVC
sewer
pipe
elbow
J.
Tightly
pack
gravel
or
sand
completely
around
pipe.
K.
42
ft
(12.8
m)
max.
L.
6"
(15.2
cm)
round
PVC
coupling
M.
6"
(15.2
cm)
minimum
N.
Window
well