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Gable Vent
Gas Vent
Ventilated Attic
Top Above Insulation
Outlet Air (1)
Ventilated Crawl Space
alternate Inlet Air (1)
COMBUSTION & VENTILATION AIR
For Single Pipe Installation
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury or
death.
Use methods described here to provide combustion and
ventilation air.
Furnaces require ventilation openings to provide sufficient air for
proper combustion and ventilation of flue gases. All duct or
openings for supplying combustion and ventilation air must
comply with the gas codes, or in the absence of local codes, the
applicable national codes.
Combustion and ventilation air must be supplied in accordance
with one of the following:
NOTE:
The Combustion & Ventilation Air Section in this
document, uses tables and information from the ANSI
Z223.1/NFPA 54. For use in Canada, use CSA B149.1 for this
information.
1. Section 9.3, Air for Combustion and Ventilation, of the
National
Fuel
Gas
Z223.1- -2009/NFPA 54- -2009 in the U.S.,
2. Sections 8.2, 8.3, 8.5, 8.6, 8.7, and 8.8 of National Stand-
ard of Canada, Natural Gas and Propane Installation Code
(NSCNGPIC), CSA B149.1- -10 in Canada,
3. Applicable provisions of the local building code.
This furnace can NOT be common vented or connected to any
type B, BW or L vent or vent connector, nor to any portion of a
factory- -built or masonry chimney. Multistory venting is NOT
permitted.
If
this
furnace
common-vented furnace, it may be necessary to resize the
existing vent and chimney to prevent oversizing problems for the
other remaining appliance(s). See "Venting and Combustion Air
Check" in this section. This furnace MUST be vented to the
outside.
When the installation is complete, check that all appliances have
adequate combustion air and are venting properly. See Venting
This installation NOT approved in Canada
alternate Inlet Air (1)
Gas Vent
Ventilated Attic
Soffit Vent
Top Above Insulation
OutletAir (1)
Inlet
Air (1)
Fig. 5 - - Outside Air
(This is ONLY a guide. Subject to codes of country having jurisdiction).
Code,
(NFGC),
ANSI
is
replacing
a
previously
Gas Vent
Gable Vent
Outlet
Air (1)
Inlet
Soffit Vent
Air (1)
Minimum One Inlet and One Outlet Air Supply is Required
Inlet
May be in any Combination Shown
Air (2)
Inlet Air Opening Must be Within12 in. (304.8mm) of floor
Outlet Air Opening Must be Within12 in. (304.8mm) of ceiling
(1) 1 Square Inch per 4000 BTUH
(2) 1 Square Inch per 2000 BTUH
And Combustion Air Check in "Gas Vent Installation" Section in
this manual.
Outdoor Combustion Air Method
A space having less than 50 cubic feet per 1,000 BTUH (4.8
3
M
/kW) input rating for all gas appliances installed in the space
requires outdoor air for combustion and ventilation.
Air Openings and Connecting Ducts
1. Total input rating for all gas appliances in the space
MUST be considered when determining free area of open-
ings.
2. Connect ducts or openings directly to the outdoors.
3. When screens are used to cover openings, the openings
MUST be no smaller than
4. The minimum dimension of air ducts MUST NOT be less
than 3" (76 mm).
5. When sizing a grille, louver, or screen use the free area of
opening. If free area is NOT stamped or marked on grill or
louver, assume a 20% free area for wood and 60% for met-
al. Screens shall have a mesh size not smaller than
mm) .
Confined Space Installation
NOTE: A confined space is defined as an area with less than 50
3
cubic feet per (1.4
M) 1,000 BTUH (2.33 cm
for all gas appliances installed in the area.
Requirements
1. Provide the space with sufficient air for proper combustion
and ventilation of flue gases using horizontal or vertical
ducts or openings.
2. Fig. 5 illustrates how to provide combustion and ventila-
tion air when two permanent openings, one inlet and one
outlet, are used.
a. One opening MUST commence within 12" (305 mm)
of the floor and the second opening MUST commence
within 12" (305 mm) of the ceiling.
b. Size openings and ducts per Table 1.
c. Horizontal duct openings require 1 square inch of free
area per 2,000 BTUH (1,1 cm
for all gas appliances in the space (see Table 1).
9
Outlet
Air (2)
Inlet
Air (2)
A07704
1
/
" (6 mm) mesh.
4
1
/
" (6
4
2
/kW) input rating
2
/kW) of combined input
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