0 mechanical (cont'd), 3 venting and combustion air (cont'd), Combustion air pipe – Reznor SC Duct Furnace Unit Installation Manual User Manual
Page 10
Form I-SC, P/N 207696 R11, Page 10
Vent Pipe
2) Venter Outlet and
Combustion Air Inlet
Since all separated combustion units
MUST BE equipped with both combustion air and
exhaust piping to the outdoors, all have inlet and outlet connections. Combustion air
inlet has a 6" I.D. collar. Venter outlet has a 6" O.D. collar.
A minimum of 12" (305mm) of straight pipe is required at the venter outlet.
Combustion Air Pipe
• Sealed, single-wall galvanized pipe is recommended for combustion air.
• Note if using 7" pipe, use
a taper type enlarger
to attach vent pipe and
7" reducer to attach
combustion air pipe.
Taper-type
Reducer
Airflow
Taper-type
Enlarger
Airflow
Diameters of Outdoor
Concentric Pipes
3) Pipe Length
and Diameter
Pipe diameter and length requirements listed for the indoor sections of pipe (between
the heater and the concentric adapter box) are in the table below. Vent pipe diameters
and maximum indoor vent lengths apply to both
horizontal and vertical vents. Add
all straight sections and equivalent lengths for elbows. The total length of the straight
sections and elbows must not exceed the
Maximum Length.
The diameters of the outside (terminal) concentric pipes are shown in the concentric
box connection illustrations in
FIGURES 9A and 9B, page 13. The outdoor lengths
depend on the installation. Outdoor vent length requirements are listed in the installa-
tion instructions for the horizontal and vertical vent/combustion air kits on pages 14-20.
6.0 Mechanical
(cont'd)
Venter Outlet Connection (diameter)
SC
100
125
150
175 200
225
250
300
350
400
inches
6
6
6
6
6
6
6
6
6
6
mm
152
152
152
152
152
152
152
152
152
152
Combustion Air Inlet Connection (diameter)
SC
100
125
150
175 200
225
250
300
350
400
inches
6
6
6
6
6
6
6
6
6
6
mm
152
152
152
152
152
152
152
152
152
152
Model SC
All Sizes
Inlet Air Pipe Diameter
8" (203mm)
Vent Pipe Diameter
5" (127mm)
6.3 Venting and
Combustion Air
(cont'd)
•
Minimum length between
the heater and the
concentric adapter box is
5 feet (1.5M).
Pipe Diameter and
Maximum Pipe Length
Between the Heater and
the Concentric Adapter
Box
Pipe Diameter and Maximum Pipe Length from Heater to Concentric Adapter
SC
Pipe Diameter
Maximum
Length
Equivalent Straight Length for a
Vent Pipe Inlet Air Pipe
90° Elbow
45° Elbow
inches mm inches mm
feet
M
feet
M
feet
M
100
6
152
6
152
40
12
8
2.4
4
1.2
125
6
152
6
152
50
15
8
2.4
4
1.2
150
6
152
6
152
50
15
8
2.4
4
1.2
175
6
152
6
152
50
15
8
2.4
4
1.2
200
6
152
6
152
50
15
8
2.4
4
1.2
7
178
7
178
70
21
8
2.4
4
1.2
225
6
152
6
152
50
15
8
2.4
4
1.2
7
178
7
178
70
21
8
2.4
4
1.2
250
6
152
6
152
50
15
8
2.4
4
1.2
7
178
7
178
70
21
8
2.4
4
1.2
300
6
152
6
152
50
15
8
2.4
4
1.2
7
178
7
178
70
21
8
2.4
4
1.2
350
6
152
6
152
30
9
8
2.4
4
1.2
7
178
7
178
70
21
8
2.4
4
1.2
400
6
152
6
152
30
9
8
2.4
4
1.2
7
178
7
178
70
21
8
2.4
4
1.2
• Vent pipe approved for a Category III appliance
OR single-wall, 26-gauge or
heavier galvanized (or a material of equivalent durability and corrosion resistance)
vent pipe is
required between the heater and the concentric adapter box.
• Double-wall (Type B) vent pipe is
required for vent terminal section. The length
of vent pipe that extends through the box and runs concentric through the
combustion air pipe must be one-piece with no joints.
Specific Venting Requirements (cont'd)