Lennox MERIT ML193UH Installation Instructions Manual page 28

7 − 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 24"
(610mm) as shown in figures 37 and 38. In addition,
close coupled wall termination kits must be extended
for use in this application. See figures 46 and 47.
When exhaust and intake piping must be run up an
outside wall, the exhaust piping must be terminated
B
2
E
B
2
A
1
The exhaust termination tee should be connected to the 2" or 3" PVC flue pipe as shown in the illustration. Do
not use an accelerator in applications that include an exhaust termination tee. The accelerator is not required.
2
As required. Flue gas may be acidic and may adversely affect some building materials. If a side wall vent
termination is used and flue gases will impinge on the building materials, a corrosion−resistant shield (24 inches
square) should be used to protect the wall surface. If optional tee is used, the protective shield is recom-
mended. The shield should be constructed using wood, sheet metal or other suitable material. All seams, joints,
cracks, etc. in affected area, should be sealed using an appropriate sealant.
3
Exhaust pipe 45° elbow can be rotated to the side away from the combustion air inlet to direct exhaust away
from adjacent property. The exhaust must never be directed toward the combustion air inlet.
D
C
1
A
D
1
12"
C
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.
8 − A multiple furnace installation may use a group of up to
four terminations assembled together horizontally, as
shown in figure 42.
Intake
TABLE 9
A− Clearance above
grade or average snow
12" (305MM) Min.
accumulation
B−Horizontal
6" (152MM) Min.
separation between
24" (610 MM) Max
intake and exhaust
C−Minimum from
end of exhaust to
9" (227MM) Min.
inlet of intake
12" (305MM) Min.
D−Exhaust pipe length
16" (405 MM) Max.
E−Wall support distance
from top of each pipe
6" (152MM) Max.
(intake/exhaust)
FIGURE 39
Page 28
B
D
C
3
Front View of
A
Intake and Exhaust
Exhaust
Intake
2" (51mm)
3" (76mm)
Vent Pipe
Vent Pipe
12" (305MM) Min.
6" (152MM) Min.
24" (610 MM) Max
9" (227MM) Min.
12" (305MM) Min.
20" (508MM) Max.
6" (152MM) Max.
Exhaust