23
How to Read the Venting Chart
The chart below applies to co-axial roof or wall
termination.
1. Maximum 18 inches horizontal pipe section
allowed with no vertical in vent system.
45 degrees elbow ok on horizontal plane.
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.
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.
Venting
Co-axial
Allowable Co-Axial Vent Con
fi
gurations
with restrictor positions
Venting Chart
Example 1
V Value = V1 (3’) + V2 (2’) + V3 (2’)= 7’
H Value = H1 (3’) + H2 (2’) = 5’
Restrictor position #3 required
2
4
6
8
10
12
14
16
18
20
VE
RT
IC
AL
RI
SE
(f
t)
HORIZONTAL RUN (ft)
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
NO INSTALLATION
Position #3
Position #2
Position #4
Position #5
Example 1
No restrictor
NO INSTALLATION
