16
Vertical Vent Termination (Single Pipe)
Alternate Vertical Vent Termination (Single Pipe)
Standard Horizontal Vent Termination (Single Pipe)
Standard Horizontal Vent Termination (Single Pipe)—
Above 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 prevent 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 weathertight,
corrosion resistant flashing. Both the combustion air intake and
vent/flue pipe terminations must be in the same atmospheric
pressure zone. See “Termination Locations,” or “Concentric Vent
Termination” in this section for specific details on termination
constructions. For details concerning connection of pipes to the
furnace, refer to the “Standard Furnace Connections” or
“Alternate Furnace Connections” in this section.
Vent/Flue and Combustion Air Pipe
Lengths and Diameters
Refer to the following table for applicable length, elbows and pipe
diameter for construction of the vent/flue and combustion air
intake pipe systems of a direct vent (dual pipe) installation. The
number of elbows tabulated represents the number of elbows
and/or tees in each vent/flue and combustion air intake pipe.
Elbows and/or tees used in the terminations must be included
when determining the number of elbows in the piping systems.
If the combustion air intake pipe is to be installed above a
finished ceiling or other area where dripping of condensate will
be objectionable, insulation of the combustion air pipe may be
required. Use
¹⁄₂
" (1.3 cm) thick closed-cell foam insulation where
required.
A. Tee (optional)
B. 12" (30.5 cm) minimum to roof or
highest anticipated snow level
A. 90º medium radius elbows
B. 12" (30.5 cm) minimum to roof or
highest anticipated snow level
A. Inside building
B. Wall
C. Outside building
D. Tee or 90º elbow turned
down
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
A
B
B
A
B
A
B
C
D
G
H
E
F
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
A
B
C