12
Determine Vent Pipe Direction
The vent system of the furnace must be self-supporting and must
not apply any weight load to the combustion blower.
Combustion Air Sources
There are 2 sources for combustion air:
1. From outside the building (Direct Vent)
2. From inside the building (Nondirect Vent)
Please read the information provided here about Vertical and
Horizontal Venting, then find and follow the instructions for your
venting configuration.
Vertical Venting
A vertical vent should extend through the roof a minimum of 2 ft
and not be obstructed a minimum of 10 ft in any direction.
Horizontal Venting
The vent terminal location shall comply with the National Fuel
Gas Code (ANSI Z223.1) or local requirements. For informational
purposes, the side wall terminal vent clearances are shown in the
Sidewall Vent Terminal Clearances tables.
Sidewall Vent Terminal Clearances—Direct Vented Furnaces (Horizontal Venting)
U.S. Installations
1
A
Clearance above grade, veranda, porch, deck, or balcony
12"
B
Clearance to window or door that may be opened
6" for appliances less than 10,000 Btu/h, 9" for appliances
greater than 10,000 Btu/h, and less than or equal to
50,000 Btu/h, 12" for appliances greater than 50,000 Btu/h
C
Clearance to permanently closed window
*
D
Vertical clearance to ventilated soffit located above the
terminal within a horizontal distance of 2 ft from the center
line of the terminal
*
E
Clearance to unventilated soffit
*
F
Clearance to outside corner
*
G
Clearance to inside corner
*
H
Clearance to each side of center line extended above
meter/regulator assembly
*
I
Clearance to service regulator vent outlet
*
J
Clearance to nonmechanical air supply inlet to building or
the combustion air inlet to any other appliance
6" for appliances less than or equal to 10,000 Btu/h, 9" for
appliances greater than 10,000 Btu/h, and less than or equal to
50,000 Btu/h, 12" for appliances greater than 50,000 Btu/h
K
Clearance to a mechanical air supply inlet
3 ft above if within 10 ft horizontally
L
Clearance above paved sidewalk or paved driveway
located on public property
*
M
Clearance under veranda, porch, deck, or balcony
*
1
In accordance with the current ANSI Z2223.1/NFPA 54, National Fuel Gas Code.
*Clearance in accordance with local installation codes and the requirements of the gas supplier and the manufacturer’s installation
instructions.
Vent Terminal
Air Supply Inlet
Area Where Terminal Is
Not Permitted
V
X
Summary of Contents for WGFBLT
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Page 26: ...26 Notes ...
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