▶ Do not reduce the vent pipe size.
▶ Do not put an elbow directly on top of
heater. Failure to follow venting
requirements may cause dangerous
exhaust gases to enter living space.
▶ Minimum vent pipe diameter: 4 inches
▶ Minimum vertical vent height: 6 feet, with no elbows
▶ Establish 12 inch rise before any elbow
The heater must be vented to the outside following all local
ordinances and specifications for installing a gas appliance
vent or chimney. The heater must be located as close as
practicable to a vertically rising chimney or vent that has a
listed vent cap at its termination point. The venting system
must be designed and constructed so as to develop a positive
flow adequate to remove flue gasses to the outdoors. Consult
the National Fuel Gas Code if the vent will have elbows or share
venting with another natural draft appliance.
▶ Do not combination vent with a
mechanically vented appliance.
4.6.1 Horizontal venting
▶ Horizontally venting to a vertically
constructed vent stack along an outside
wall of a building is not permissible.
▶ Horizontally venting to a sidewall vent
terminator is not permissible.
4.6.2 Vertical venting
▶ A 4 inch diameter gas vent constructed of double wall Type
B gas vent is recommended. Under no circumstances
should the vent pipe be reduced in size.
▶ An approved gas vent connector must be attached to the
top of the water heater and rise vertically at least 12"
before entering into an approved gas vent connector
▶ The minimum vertical gas vent height allowed is 6 feet;
horizontal vent connectors and elbows are not to be
considered in the total gas vent height.
▶ All gas vent sections must be secured to each other with
sheet metal screws and be properly supported.
Any gas vent section that is greater than 45 degrees from the
vertical is considered horizontal. Horizontal sections must
slope upwards at least ¼ inch for every foot of its horizontal
length and be properly supported. Keep the horizontal section
short and avoid too many elbows. The maximum horizontal run
allowed is half of the total vertical vent height; horizontal vent
connectors and elbows are not to be considered in the total gas
The gas vent constructed of double wall Type B gas vent must
terminate above the roof surface with a listed vent cap at a
height that's in accordance with Fig. 10 and table 5, provided
it is at least 8 feet (2.4 m) from a vertical wall or similar
obstruction. All other gas vents that are not able to terminate
within the minimum specified height allowed must terminate
not less than 2 feet (0.6 m) above the highest point where it's
passed through the roof and at least 2 feet (0.6 m) higher than
any vertical wall or similar obstruction within 10 feet (3.1 m).
ESTABLISH A ONE
FOOT RISE BEFORE
 Listed vent cap
 Listed gas vent
[A] Minimum 6 feet (1,8m)
Masonry chimneys shall be built and installed in accordance
with NFPS 211 or local codes. A minimum 4" diameter gas vent
Installation instructions | 13
6 720 644 951 (2014/11)