4
DIRECT VENT —Vertical Through Roof or Unused Chimney
DIRECT VENT
INSTALLATION OF VENT &
COMBUSTION AIR PIPING
A Direct Vent appliance uses uncontaminated
outdoor air (piped directly to the appliance) for
combustion.
Vertical Through Roof or Unused
Chimney
NOTICE
Installation of vent and combustion air
piping must comply with local codes and
requirements and with the National Fuel
Gas Code NFPA 54, ANSI Z223.1 for in-
stallations in the U.S. or CSA B149.1 or
B149.2 for installations in Canada.
NOTICE
When using an unused chimney as a
means of a chase for the vent, the sur-
rounding space within the chimney can-
not be used to draw combustion air or
vent another appliance.
WARNING
A GAS VENT EXTENDING THROUGH AROOF
SHOULD NOT TERMINATE NEAR AN ADJACENT
WALL OR BELOW ANY BUILDING EXTENSIONS SUCH
AS ROOF EAVES, BALCONIES OR DECKS. FAILURE
TO COMPLY WITH THE REQUIRED CLEARANCES IN
THIS MANUAL COULD RESULT IN PERSONAL INJU-
RY, DEATH OR PROPERTY DAMAGE.
PIPING LENGTH & TERMINATIONS
NOTICE
The length of the vent or combustion air
piping must not exceed 100 feet reduced
as follows:
◦For every 45° elbow deduct 3 feet
◦For every 90° elbow deduct 5 feet
NOTICE
Do not include the exterior termination fit-
tings in determining total pipe length.
• Combustion air piping must terminate in an
upside down “U” shape using two 90º el-
bows as shown in Figure 2 on page 6 or with
a tee as shown in Figure 3 on page 6. Ter-
mination must be installed 12” [18” Canada]
above the highest anticipated snow level.
• The vent must terminate vertically with a cou-
pling to accept the bird screen and must be
located 12” to 24” above the combustion air
inlet as shown on page 6.
• The vent and combustion air terminations
must be located a radial distance of 12” to
24” from center-line of vent termination to
center-line of air termination as shown on 6.
• The following should be considered when
determining the location of the vent and
combustion air terminations:
◦Avoid areas where the vent termination
flue vapors might damage landscaping or
equipment.
◦Avoid terminating the vent where conden-
sation plume could obstruct window.
◦Avoid areas where prevailing winds might
cause freezing of flue gas moisture result-
ing in a buildup of water or ice.
◦Avoid locations where prevailing winds
could affect performance or cause recir-
culation of the flue gases—such as inside
corners of buildings, near adjacent build-
ings, vertical surfaces, alcoves, court-
yards, or other recessed areas.
◦Do not terminate the vent above or below
doors or windows.
◦Locate the vent termination to prevent
moisture damage to exterior finishes.
◦Avoid locations of possible contact
between flue vapors and people or pets.
• The vent termination must maintain the fol-
lowing clearances. See Figure 1.
◦At least 3 feet from adjacent walls
◦At least 3 feet below roof over hangs
◦At least 7 feet above any public walkways
GF-125V
