Allied Air A96US2V Installation Instructions Manual page 29

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 gasses may impinge on the building
material, a corrosion resistant shield (minimum 24 inches
square) should be used to protect the wall surface. If the
optional tee is used, the protective shield is recommended.
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 38.
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 33 through 44 show typical terminations.
1. Intake and exhaust terminations are not required to be
in the same paressure zone. You may exit the intake
on one side of the structure and the exhaust on another
side (Figure 34). You may exit the exhaust out the roof
and the intake out the side of the structure (Figure 35).
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 sidewall terminations.
3. On roof terminations, the intake piping should terminate
straight down using two 90° elbows (See Figure 33).
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 7.
DIRECT VENT ROOF TERMINATION KIT
(15F75 OR 44J41)
Figure 33
507404-04
Exiting Exhaust and Intake Vent
Exiting Exhaust and Intake Vent
Issue 1621
(no common pressure zone)
Figure 34
(no common pressure zone)
Figure 35
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