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Details of Intake and Exhaust Piping Terminations for
Direct Vent Installations
NOTE − In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged to outdoors.
Intake and exhaust pipes may be routed either horizontally
through an outside wall or vertically through the roof. In at-
tic or closet installations, vertical termination through the
roof is preferred. Figures 25 through 32 show typical ter-
minations.
1 − Exhaust and intake exits must be in same pressure
zone. Do not exit one through the roof and one on the
side. Also, do not exit the intake on one side and the
exhaust on another side of the house or structure.
2 − Intake and exhaust pipes should be placed as close
together as possible at termination end (refer to il-
lustrations). Maximum separation is 3" (76mm) on roof
terminations and 6" (152mm) on side wall termina-
tions.
3 − If necessary, install a field−provided transition to adapt
larger vent pipe size to termination pipe size.
4 − On roof terminations, the intake piping should termi-
nate straight down using two 90° elbows (See figure
25).
5 − Exhaust piping must terminate straight out or up as
shown. In rooftop applications, a reducer may be re-
quired on the exhaust piping at the point where it exits
the structure to improve the velocity of exhaust away
from the intake piping. See table 8.
NOTE − Care must be taken to avoid recirculation of
exhaust back into intake pipe.
6 − On field supplied terminations for side wall exits, ex-
haust piping should extend a maximum of 12 inches
(305mm) beyond the outside wall unless supported.
Intake piping should be as short as possible. See fig-
ure 24.
7 − On field supplied terminations, the end of the exhaust
pipe must extend a minimum of 8" (203mm) beyond
the end of the intake pipe.
8 − If intake and exhaust piping must be run up a side wall
to position above snow accumulation or other ob-
structions, piping must be supported every 3 ft. (.9m)
as shown in figure 18. Refer to figure 28 for proper
piping method. In addition, the wall termination kit
must be extended for use in this application. See fig-
ure 30. When exhaust and intake piping must be run
up an outside wall, the exhaust piping must be termi-
nated with pipe sized per table 8. The intake piping
may be equipped with a 90° elbow turndown. Using
turndown will add 5 feet (1.5m) to the equivalent
length of the pipe.
9 − Based on the recommendation of the manufacturer, a
multiple furnace installation may use a group of up to
four wall termination kits assembled together horizon-
tally, as shown in figure 31.
TABLE 8
EXHAUST PIPE TERMINATION SIZE REDUCTION
G71MPP
MODEL
Exhaust Pipe Size Termination Pipe Size
070 2", 2−1/2", 3" or 4" 1−1/2"
090 2", 2−1/2", 3" or 4" 2"
110 2−1/2", 3" or 4" 2"*
135 3" or 4" 2"*
*Approved 3" concentric termination kit terminates with 2−5/8" ID pipe.
SIZE
TERMINATION
PIPE PER
TABLE 8.
1/2 (13) ARMAFLEX
INSULATION IN
UNCONDITIONED SPACE
12 (305) MAX.
6 (152)
MAXIMUM
2 (51) PVC
COUPLING
8 (203)
MINIMUM
OUTSIDE
WALL
Inches (mm)
TOP VIEW WALL RING KIT WITH STRAIGHT INTAKE
(15F74)
1/2" (13)
ARMAFLEX
INSULATION
FIELD−
PROVIDED
REDUCER MAY
BE REQUIRED
TO ADAPT
LARGER VENT
PIPE SIZE TO
TERMINATION
TOP VIEW WALL RING KIT WITH 90° ELBOW ON INTAKE
(15F74)
FIGURE 24
SIZE
TERMINATION
PIPE PER
TABLE 8.
1/2 (13) ARMAFLEX
INSULATION IN
UNCONDITIONED SPACE
12 (305) MAX.
6 (152)
MAXIMUM
4 (102)
MINIMUM
OUTSIDE
WALL
Inches (mm)
1/2" (13)
ARMAFLEX
INSULATION
FIELD−
PROVIDED
REDUCER MAY
BE REQUIRED
TO ADAPT
LARGER VENT
PIPE SIZE TO
TERMINATION
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