34
2
4
6
8
10
12
14
16
18
20
VERTICAL
RISE (ft)
HORIZONTAL RUN (ft)
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
4 x 90º ELBOWS MAXIMUM
(or equivalent)
V2
V1
V3
H2
H1
45° elbow take-off
supplied with unit
Max. 12” pipe length
with no vertical rise
1” min.
all around
vertical pipe
3” min.
above top of
horizontal pipe
1” min. around
bottom & sides
of horizontal pipe
Use 845TG vent
guard with a
vent terminal
located at less
than 7’ (2.13 m)
above grade
Allowable Co-Axial Vent Con
fi
gurations with
restrictor positions
NO INSTALLATION
Position #2
Position #1
Position #3
Position #4
Example 1
No restrictor
How to Read the Venting Chart
The chart below applies to co-axial roof or wall
termination.
1. Maximum 12 inch horizontal pipe section allowed
with no vertical in vent system.
2. The total length of the vent pipe cannot exceed
40 feet.
3. The minimum vertical height with roof termination
is 6 feet.
4. Any combination of rise and run can be used as
long as they are within the allowable limits shown
on the chart below.
5. A maximum of 4 x 90 degrees elbows—or
equivalent (2 x 45 degrees = 90 degrees)—can
be used. Excludes the 45 degrees take-off elbow
shipped with the appliance.
6. Each 90 degrees elbow installed on the horizontal
plane is equivalent to a 3 feet horizontal pipe;
therefore, 3 feet must be subtracted from allowable
horizontal run. (45 degrees elbow is equivalent to
18 inches horizontal pipe.)
7. All horizontal pipe runs must be graded 1/4 inch per
foot upwards in the direction of the exhaust fl ow.
The fi nal pipe length, when terminating through the
wall may be graded downwards slightly to prevent
water migration.
8. A restrictor adjustment is required for most
installations having a vertical rise—see next
section.
Note:
The restrictors are shipped loose with the
appliance.
Co-axial Venting
Venting Chart
Example 1
V Value = V1 (3’) + V2 (2’) + V3 (1’)= 6’
H Value = H1 (3’) + H2 (2’) = 5’
Restrictor position #1 required
NO INSTALLATION
QUALIFIED
INSTALLER
