Filter
Top Products
506725-01 Page 21 of 48
Issue 1109
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.
NOTE: Flue gas may be slightly acidic and may adversely
affect some building materials. If any vent termination is
used and the flue gases may impinge on the building
material, a corrosion-resistant shield (minimum 24 inches
square) must be used to protect the wall surface. If the
optional tee is used, the protective shield is required. The
shield should be constructed using wood, plastic, sheet metal
or other suitable material. All seams, joints, cracks, etc. in
the affected area should be sealed using an appropriate
sealant. See Figure 27.
Intake and exhaust pipes may be routed either horizontally
through an outside wall or vertically through the roof. In
attic or closet installations, vertical termination through the
roof is preferred. Figures 25 through 33 show typical
terminations.
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
illustrations). Maximum separation is 3" (76 mm) on
roof terminations and 6" (152 mm) on side wall
terminations.
3. On roof terminations, the intake piping should terminate
straight down using two 90° elbows (See Figure 25).
4. Exhaust piping must terminate straight out or up as
shown. A reducer may be required 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.
6. On field supplied terminations, a minimum distance
between the end of the exhaust pipe and the end of the
intake pipe without a termination elbow is 8" and a
minimum distance of 6" with a termination elbow. See
Figures 28 and 29.
7. If intake and exhaust piping must be run up a side wall
to position above snow accumulation or other
obstructions, piping must be supported every 24" (610
mm) as shown in Figures 28 and 29.
When exhaust and intake piping must be run up an
outside wall, the exhaust piping must be terminated with
pipe sized per Table 8. The intake piping may be
equipped with a 90° elbow turndown. Using turndown
will add 5 feet (1.5 m) to the equivalent length of the
pipe.
8. Based on the recommendation of the manufacturer, a
multiple furnace installation may use a group of up to
four terminations assembled together horizontally, as
shown in Figure 32.
TABLE 8
EXHAUST PIPE TERMINATION SIZE REDUCTION
MODEL Exhaust Pipe Size
Termination
Pipe Size
*045 and *070
2" (51mm), 2−1/2" (64mm),
3" (76mm)
1−1/2" (38mm)
*090 2" (51mm)
110
3" (76mm)
2" (51mm)
*045, 070 and 090 units with the ush−mount termination
must use the 1−1/2"accelerator supplied with the kit.
5. On field supplied terminations for side wall exit, exhaust
piping may extend a maximum of 12 inches (305 mm)
for 2" PVC and 20 inches (508 mm) for 3" (76 mm) PVC
beyond the outside wall. Intake piping should be as
short as possible. See Figures 28 and 29.
NOTE: Care must be taken to avoid recirculation of exhaust
back into intake pipe.
2" EXTENSION
FOR 2" PVC PIPE
1" EXTENSION
FOR 3" PVC PIPE
FIGURE 26
1−1/2" ACCELERATOR
(
all −45, −070 and −090 units)
FURNACE
EXHAUST
PIPE
FURNACE
INTAKE PIPE
4’’
GLUE EXHAUST
END FLUSH INTO
TERMINATION
FLAT SIDE
FLUSH−MOUNT SIDE WALL TERMINATION
51W11
FIGURE 25
UNCONDITIONED
ATTIC SPACE
1/2" (13mm) FOAM
INSULATION IN
UNCONDITIONED
SPACE
SIZE TERMINATION
PIPE PER TABLE 8.
3"(76mm) MAX.
12" (305mm) ABOVE
AVERAGE SNOW
ACCUMULATION
3" (76mm) OR
2" (51mm) PVC
PROVIDE SUPPORT
FOR INTAKE AND
EXHAUST LINES
8" (203mm) MIN
Inches(mm)
DIRECT VENT ROOF TERMINATION KIT
(15F75 or 44J41)
(IF REQUIRED)