International comfort products N9MSB Installation Instructions Manual page 41

INSTALLATION INSTRUCTIONS
Figure 47 Combustion Air and Vent Pipe Termination for Direct Vent (2−Pipe) System
Vertical separation between
combustion air and vent
8 ¾ in. (222mm) for 3 in.(76mm)
6 ¾ in. (172mm) for 2in. (51mm)
Maintain 12 in. (305mm)
min. Clearance above
highest anticipated snow
level maximum of 24 in.
(614mm) above roof
Figure 48 Vent Pipe Termination for Non−Direct Vent and Ventilated Combustion Air System
Size the Vent and Combustion Air Pipes
General
Furnace combustion air and vent pipe connections are sized
for 2-in. (50 mm ND) PVC/ABS DWV pipe. The combustion air
and vent pipe connections
polypropylene venting systems with outside diameters of
approximately 60 mm (2−3/8 inches). Any pipe diameter
change should be made outside furnace casing in vertical pipe.
440 01 4101 03
Roof Termination (Preferred)
At least 36 in.
(914mm)
A
18 in. Maximum
(457mm)
Abandoned masonry used
as raceway (per code)
Concentric Vent and Combustion Air
Side Termination
12 in. Min from
overhang or
roof (Typ.)
90 0
A
At least 36 in.
(914mm)
Roof Termination (Preferred)
Maintain 12 in (305mm) .
minimum clearance
above highest anticipated
snow level maximum of
24 in. (610mm) above roof .
90°
Side wall termination
with 2 elbows (preferred)
also accommodate 60mm
Specifications subject to change without notice.
Note:
"A" denotes 0 To 2 in. (51mm)
Between the first 2 vents Third
vent (and fourth vent, if used)
must be 36 in. Away (914mm)
A
At least 36 in.
(914mm)
Concentric Vent and Combustion Air
Roof Termination (preferred)
A
Note:
At least 36 in.
"A" denotes 0 To 2 in. (51mm)
(914mm)
Between the first 2 vents Third
vent (and fourth vent, if used) must
12 in. (305mm) separation
be 36 in. Away (914mm)
between bottom of com
bustion air and bottom of
vent (Typ.)
Maintain 12 in. (305mm) min.
Clearance above highest an
ticipated snow level or grade
whichever is greater (Typ.)
Vent
Abandoned masonry
used as raceway
(per code)
6 in. (152mm) minimum clearance
between wall and end of vent pipe.
10 in. (254mm) maximum pipe lengt h
12 in. (305 mm) min. from
overhang or roof
Maintain 12 in. (305mm)
minimum clearance
above highest anticipated
snow level or grade
whichever is greater.
Any change in diameter to the pipe must be made as close to
the furnace as reasonably possible.
The Maximum Vent Length for the vent pipe and combustion air
pipe (when used) equals the Maximum Equivalent Vent Length
(MEVL) in Table 14 or Table 16, minus the number of fittings
multiplied by the deduction for each type of fitting used from
Table 15.
Gas Furnace: N9MSB, N9MSE
Note:
36 in. separation between
pairs of inlets only required
for direct vent systems
Maintain 12 in. (305mm) min. Clearance
above highest anticipated snow level
maximum of 24 in. (614mm) above roof
1 in. (25mm) maximum
(Typ.) from wall to inlet
12 in. From Overhang
or roof (Typ.)
A
Maintain 12 in. (305mm) min. Clear
At least 36 in. ance above highest anticipated snow
(914mm) level or grade whichever is greater
(Typ.)
Side wall termination of
less than 12 in. (305mm)
above highest snow level
L12F044
12 in. min. (305 mm)from
overhang or roof
Maintain 12 in. (305mm)
minimum clearance
above highest anticipated
snow level or grade
whichever is greater
Sidewall Termination
with Straight Pipe (preferred)
A05091
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