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Standard Horizontal Vent Termination (Single Pipe)
B
A
H
A. Inside building
B. Wall
C. Outside building
D. Tee or 90º elbow turned
down
Standard Horizontal Vent Termination (Single Pipe)—
Above Highest Anticipated Snow Level
A
A. 12" (30.5 cm) minimum from wall
B. Tee or 90º elbow turned down
C. 12" (30.5 cm) minimum to roof or highest anticipated snow level
Direct Vent (Dual Pipe) Piping
The inlet air screens provided in the installation instruction packet
are available for the installer to use in the inlet of the combustion
air pipe to keep animals from building nests in the combustion air
pipe. Installation of screens, while strongly recommended, is not
required and will not affect performance of the furnace.
Direct vent installations require both a combustion air intake and
a vent/flue pipe. The pipes may be run horizontally and exit
through the side of the building or run vertically and exit through
the roof of the building. The pipes may be run through an existing
unused chimney; however, they must extend a minimum of 12"
(30.5 cm) above the top of the chimney. The space between the
pipes and the chimney must be closed with a weather tight,
corrosion resistant flashing. Both the combustion air intake and a
vent/flue pipe terminations must be in the same atmospheric
pressure zone. See "Vent/Flue and Combustion Air Pipe
Terminations," "Concentric Vent Termination," "Vent Pipe
Installation—Standard Furnace Connections" or "Vent Pipe
Installation—Alternate Furnace Connections."
Vent/Flue and Combustion Air Pipe Terminations
The vent/flue and combustion air pipes may terminate
vertically, as through a roof, or horizontally, as through an
outside wall.
The penetrations through the roof must be sealed tight with
proper flashing such as is used with a plastic plumbing vent.
A 2³⁄₈" (6.1 cm) diameter wall penetration is required for 2"
(5.1 cm) diameter pipe.
C
D
G
F
E
E. 12" (30.5 cm) minimum to roof or
highest anticipated snow level
F. 12" (30.5 cm) minimum from wall
G. Coupling
H. Elbow or coupling
B
C
A 3" (7.6 cm) diameter hole is required for a 2¹⁄₂" (6.4 cm)
pipe.
A 3¹⁄₂" (8.9 cm) diameter hole is required for 3" (7.6 cm)
diameter pipe.
To secure the pipe passing through the wall and avoid
damage to piping connections, a coupling should be installed
on either side of the wall and solvent cemented to a pipe
connecting the 2 couplings.
The pipe length should be the wall thickness plus the depth
of the socket fittings to be installed on the inside and outside
of the wall.
The wall penetration should be sealed with silicone caulking
material.
In a basement installation, the pipes may be run between the
floor joist spaces.
NOTE: If the pipes must go below the floor joist and then up
into the last floor joist space to penetrate the header, two 45°
elbows should be used to reach the header rather than two
90° elbows.
Vertical Vent Terminations (Dual Pipe)
B
A
G
H
A. 12" (30.5 cm) minimum
B. Combustion air intake
C. 90º medium radius elbows
D. Tee
E. Vent/flue pipe
Standard Horizontal Vent Terminations (Dual Pipe)
A
G
F
A. 24" (61 cm) maximum, 3"
(7.6 cm) minimum
B. 12" (30.5 cm) minimum from
wall
C. Tee or 90º elbow turned
down
D
E
C
F
F. 24" (61 cm) maximum, 3" (7.6 cm)
minimum
G. Screen
H. 12" (30.5 cm) minimum to roof or
highest anticipated snow level
B
A
C
E
D
D
D. 12" (30.5 cm) minimum to roof or
highest anticipated snow level
E. Combustion air intake
F. Screen
G. 90º medium radius elbow
21
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