Lennox ML196DF045XE36B Manual page 32

Hide thumbs Also See for ML196DF045XE36B:
Table of Contents

Advertisement

Details of Intake and Exhaust Piping Terminations for
Direct Vent Installations
NOTE - In Direct Vent installations, combustion air is tak­
en from outdoors and flue gases are discharged to out­
doors.
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 ma­
terial, 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 40.
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 32 through 39 show typical ter­
minations.
1. Intake and exhaust terminations are not required to be
in the same pressure zone. You may exit the intake on
one side of the structure and the exhaust on another
side (figure 33). You may exit the exhaust out the roof
and the intake out the side of the structure (figure 34).
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.
NOTE - When venting in different pressure zones, the
maximum separation requirement of intake and ex­
haust pipe DOES NOT apply.
3. On roof terminations, the intake piping should termi­
nate straight down using two 90° elbows (See figure
32).
4. Exhaust piping must terminate straight out or up as
shown. A reducer may be required on the exhaust pip­
ing at the point where it exits the structure to improve
the velocity of exhaust away from the intake piping.
See table 15.
TABLE 15
EXHAUST PIPE TERMINATION SIZE REDUCTION
ML196
Exhaust Pipe Size
MODEL
*045 and *070
2" (51mm), 2-1/2" (64mm),
*090
3" (76mm)
110
*ML196DFE-045, -070 and -090 units with the flush-mount termina­
tion must use the 1-1/2"accelerator supplied with the kit.
5. On field-supplied terminations for side wall exit, ex­
haust piping may extend a maximum of 12 inches
(305mm) for 2" PVC and 20 inches (508mm) for 3"
(76mm) PVC beyond the outside wall. Intake piping
should be as short as possible. See figure 40.
NOTE - Care must be taken to avoid recirculation of
exhaust back into intake pipe.
Inches(mm)
12" (305mm) ABOVE
AVERAGE SNOW
ACCUMULATION
3" (76mm) OR
2" (51mm) PVC
Exhaust
Pipe
Roof T erminated
Exhaust Pipe
Termination
Pipe Size
1-1/2" (38mm)
2" (51mm)
2" (51mm)
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
figure 40.
Page 32
3"(76mm) MAX.
8" (203mm) MIN
PROVIDE SUPPORT
FOR INTAKE AND
EXHAUST LINES
DIRECT VENT ROOF TERMINATION KIT
(15F75 or 44J41)
FIGURE 32
Exiting Exhaust and Intake Vent
(different pressure zones)
Furnace
FIGURE 33
Exiting Exhaust and Intake Vent
(different pressure zones)
Furnace
FIGURE 34
SIZE TERMINATION
PIPE PER TABLE 15.
UNCONDITIONED
ATTIC SPACE
1/2" (13mm) FOAM
INSULATION IN
UNCONDITIONED
SPACE
Inlet Air
(Minimum 12 in.
305 MM) above
grade or snow
accumulation
Inlet Air
(Minimum 12 in.
305 MM) above
grade or snow
accumulation

Advertisement

Table of Contents
loading

Table of Contents