INSTALLATION INSTRUCTIONS Gas Furnace: WFAR
10 440 01 7104 02
Specifications subject to change without notice.
the furnace. Follow the guidelines below to insure that the
furnace and other gas appliances have sufficient air for
combustion.
Ventilated Combustion Air Applications
When the furnace is installed using the ventilated combustion
air option, the attic or crawlspace must freely communicate with
the outdoor to provide sufficient air for combustion. The
combustion air pipe cannot be terminated in attics or
crawlspaces that use ventilation fans designed to operate
during the heating season. If ventilation fans are present in
these areas, the combustion air pipe must terminate outdoors
as a Direct Vent/ 2-Pipe system.
All air for combustion is piped directly to the furnace from a
space that is well ventilated with outdoor air (such as an attic,
crawlspace, or equipment closet) and the space is well isolated
from the living space or garage. In addition, other gas
appliances installed in the space with the furnace may require
outside air for combustion. Follow the guidelines below to
insure that the roof or crawlspace walls have sufficient free
area to provide sufficient air for combustion and ventilation for
the furnaces. The guidelines below can be used to insure that
other gas appliances have sufficient air for combustion.
Provisions for adequate combustion, ventilation, and dilution air
must be provided in accordance with:
S U.S.A. Installations: Section 9.3 of the NFPA 54/ANSI
Z223.1--2012 , Air for Combustion and Ventilation and
applicable provisions of the local building codes.
S Canada: Part 8 of the CAN/CSA--B149.1--2010,
Venting Systems and Air Supply for Appliances.
FURNACE CORROSION HAZARD
Failure to follow this caution may result in furnace
damage.
Air for combustion must not be contaminated by
halogen compounds, which include fluoride,
chloride, bromide, and iodide. These elements can
corrode heat exchangers and shorten furnace life.
Air contaminants are found in aerosol sprays,
detergents, bleaches, cleaning solvents, salts, air
fresheners, and other household products.
CAUTION
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in
personal injury or death.
The operation of exhaust fans, kitchen ventilation
fans, clothes dryers, attic exhaust fans or fireplaces
could create a NEGATIVE PRESSURE
CONDITION at the furnace. Make--up air MUST be
provided for the ventilation devices, in addition to
that required by the furnace. Refer to the Carbon
Monoxide Poisoning Hazard warning in the venting
section of these instructions to determine if an
adequate amount of make--up air is available.
!
WARNING
The requirements for combustion and ventilation air depend
upon whether or not the furnace is located in a space having a
volume of at least 50 cubic feet per 1,000 Btuh input rating for
all gas appliances installed in the space.
S Spaces having less than 50 cubic feet per 1,000 Btuh
(4.8 cubic meters per kW) require the Outdoor
Combustion Air Method.
S Spaces having at least 50 cubic feet per 1,000 Btuh
(4.8 cubic meters per kW) may use the Indoor
Combustion Air, Standard or Known Air Infiltration
Method.
Outdoor Combustion Air Method
1. Provide the space with sufficient air for proper
combustion, ventilation, and dilution of flue gases using
permanent horizontal or vertical duct(s) or opening(s)
directly communicating with the outdoors or spaces that
freely communicate with the outdoors.
2. Figure 6 illustrates how to provide TWO OUTDOOR
OPENINGS, one inlet and one outlet combustion and
ventilation air opening, to the outdoors.
a. One opening MUST commence within 12 in. (300
mm) of the ceiling and the second opening MUST
commence within 12 in. (300 mm) of the floor.
b. Size openings and ducts per Figure 6 and Table 3.
c. TWO HORIZONTAL DUCTS require 1 sq. in. (645
sq. mm) of free area per 2,000 Btuh (1,100 mm
2
/kW)
of combined input for all gas appliances in the space
per Figure 6 and Table 3.
d. TWO OPENINGS OR VERTICAL DUCTS require 1
sq. in. (645 sq. mm) of free area per 4,000 Btuh (550
mm
2
/kW) for combined input of all gas appliances in
the space per Figure 6 and Table 3.
3. ONE OUTDOOR OPENING requires:
a. 1 sq. in. (645 sq. mm) of free area per 3,000 Btuh
(734 mm
2
/kW) for combined input of all gas
appliances in the space per Figure 6 and Table 3.
b. Not less than the sum of the areas of all vent
connectors in the space.
The opening shall commence within 12 in. (300 mm) of the
ceiling. Appliances in the space shall have clearances of at
least 1 in. (25 mm) from the sides and back and 6 in. (150 mm)
from the front. The opening shall directly communicate with the
outdoors or shall communicate through a vertical or horizontal
duct to the outdoors or spaces (crawl or attic) that freely
communicate with the outdoors.
Indoor Combustion AirE NFPA&AGA
Standard and Known--Air--Infiltration Rate
Methods
Indoor air is permitted for combustion, ventilation, and dilution,
if the Standard or Known--Air--Infiltration Method is used.
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in
personal injury or death.
Many homes require air to be supplied from
outdoors for furnace combustion, ventilation, and
dilution of flue gases.
The furnace combustion air supply must be
provided in accordance with this instruction
manual.
!
WARNING
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