31
Fig. 31: Vertical Venting
504A-1504A: 8’ OR LESS
2
004A: 10’ OR LESS
Table L: Category I Vertical Venting
1
Vent lengths are based on a lateral length of 2 ft. Refer to the latest edition of the NFGC for further details. When vertical height
exceeds 25 ft, consult factory prior to installation.
* Subtract 10 ft per elbow. Max. 4 elbows.
** Adapters supplied by others.
M
odel
No.
Certified
Vent
Material
V
ent Size
(in.)
Vertical Vent
Height
1
(ft)
Combustion Air
Intake Pipe
Material
Air Inlet
Max. Length* (ft)
Min. Max. 6” Ø 8” Ø 10” Ø
504A
Category I
(Type B
Equivalent)
8
5 25
G
alvanized
Steel,
PVC,
ABS,
CPVC
45 100**754A 10
1104A 10
1504A 12
45 85**
2004A 14
Common Venting
Manifolds that connect more than one heater to a com-
mon chimney must be sized to handle the combined
load. Consult available guides for proper sizing of the
manifold and the chimney. At no time should the area
of the common vent be less than the area of the
largest heater exhaust outlet.
Common venting systems may be too large once an
existing unit is removed. At the time of removal of an
existing appliance, the following steps must be fol-
lowed with each appliance remaining connected to the
common venting system placed in operation, while the
other appliances remaining connected to the common
venting system are not in operation.
1. Seal any unused opening in the common venting
system.
2. Visually inspect the venting system for proper size
and horizontal pitch and verify there is no block-
age, restriction, leakage, corrosion or other unsafe
condition.
WARNING: Vent connectors serving appliances
vented by natural draft shall not be connected into
any portion of mechanical draft systems operating
under a positive pressure.
CAUTION: Vent connectors for natural draft
venting systems must be Type B or better.
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