Page 43
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 24 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
24).
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 37.
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 25.
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, wall termination kit must
be extended for use in this application. See figure 31.
When exhaust and intake piping must be run up an
outside wall, the exhaust piping must be terminated
with pipe sized per table 37. 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 termination kits assembled together horizontally,
as shown in figure 30.
TABLE 37
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.
FIGURE 24
DIRECT VENT ROOF TERMINATION KIT
(15F75 or 44J41)
UNCONDITIONED
ATTIC SPACE
1/2" (13) FOAM
INSULATION IN
UNCONDITIONED
SPACE
SIZE TERMINATION
PIPE PER TABLE 37.
3(76) MAX.
12" (305) ABOVE
AVERAGE SNOW
ACCUMULATION
3" (76) OR
2" (51) PVC
PROVIDE SUPPORT
FOR INTAKE AND
EXHAUST LINES
8" (203) MIN
Inches(mm)
FIGURE 25
1/2" (13) ARMAFLEX
INSULATION IN
UNCONDITIONED SPACE
1−1/2" (38) PVC
12" (305) MAX.
(unless supported)
6" (152)
MAXIMUM
2" (51) PVC
COUPLING
8" (203)
MINIMUM
OUTSIDE
WALL
Inches (mm)
TOP VIEW WALL RING KIT
(15F74)
1/2" (13)
ARMAFLEX
INSULATION
FIELD−
PROVIDED
REDUCER MAY
BE REQUIRED
TO ADAPT
LARGER VENT
PIPE SIZE TO
TERMINATION
