I.
LOCATION
A.
General
CAUTION:
Do not install furnace in a corrosive or
contaminated atmosphere. Make sure all combustion and
circulating air requirements are met, in addition to all
local codes and ordinances.
CAUTION:
Do not use this furnace during construction
when adhesives, sealers, and/or new carpets are being
installed. If the furnace is required during construction,
use clean outside air for combustion and ventilation.
Compounds of chlorine and fluorine when burned with
combustion air form acids which cause corrosion of the
heat exchangers and metal vent system. Some of these
compounds are found in paneling and dry wall adhesives,
paints, thinners, masonry cleaning materials, and many
other solvents commonly used in the construction pro-
cess.
Excessive exposure to contaminated combustion air will
result in safety and performance related problems.
This furnace must be installed so the electrical components are
protected from water. This furnace shall not be installed directly on
carpeting, tile, or any combustible material other than wood
flooring.
Locate furnace as close to the chimney/vent and as near the center
of the air distribution system as possible. The furnace should be
installed as level as possible.
Provide ample space for servicing and cleaning. Always comply
with the minimum fire protection clearances shown on the unit
rating plate.
B.
Location Relative to Cooling Equipment
The cooling coil must be installed parallel with or on the
downstream side of the unit to avoid condensation in the heat
exchangers. When installed parallel with a furnace, dampers or
other means used to control the flow of air must prevent chilled air
from entering the unit. If the dampers are manually operated, they
must be equipped with means to prevent operation of either unit
unless the damper is in the full-heat or full-cool position.
C.
Hazardous Locations
When the furnace is installed in a residential garage, it must be
installed so that the burners and ignition source are located at least
18 in. above the floor. The furnace should be protected from
physical damage by vehicles. When a furnace is installed in public
garages, airplane hangars, or other buildings having hazardous
atmospheres, the unit must be installed in accordance with the
recommended good practice requirements of the National Fire
Protection Association, Inc.
II.
AIR FOR COMBUSTION AND VENTILATION
Provisions for adequate combustion and ventilation air must be
provided in accordance with Section 5.3 of the NFGC, Air for
Combustion and Ventilation, or applicable provisions of the local
building codes.
Canadian installations must be installed in accordance with NSC-
NGPIC and all authorities having jurisdiction.
CAUTION:
Air for combustion must not be contami-
nated by halogen compounds, which include fluoride,
chloride, bromide, and iodide. These elements are found
in aerosol sprays, detergents, bleaches, cleaning solvents,
salts, air fresheners, and other household products.
All fuel-burning equipment must be supplied with air for combus-
tion of the fuel. Sufficient air MUST be provided to ensure there
will not be a negative pressure in the equipment room or space. In
addition, a positive seal MUST be made between the furnace
cabinet and the return-air duct to prevent pulling air from the
burner area and blocked vent safeguard opening.
CAUTION:
The operation of exhaust fans, kitchen ven-
tilation fans, clothes dryers, 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.
The requirements for combustion and ventilation air depend upon
whether the furnace is located in an unconfined or confined space.
A.
Unconfined Space
An unconfined space must have at least 50 cubic ft for each 1000
Btuh of input for all the appliances (such as furnaces, clothes
dryer, water heaters, etc.) in the space.
If the unconfined space is of unusually tight construction, air for
combustion and ventilation MUST come from either the outdoors
or spaces freely communicating with the outdoors. Combustion
and ventilation openings must be sized the same as for a confined
space as defined below. Return air must not be taken from the
room unless an equal or greater amount of air is supplied to the
room.
B.
Confined Space
A confined space is defined as a space whose volume is less than
50 cu ft per 1000 Btuh of total input ratings of all appliances
installed in that space. A confined space MUST have provisions
for supplying air for combustion, ventilation, and dilution of flue
gases using 1 of the following methods. (See Fig. 4 and Table 2.)
NOTE:
In determining free area of an opening, the blocking
effect of louvers, grilles, and screens must be considered. If free
area of louver or grille design is unknown, assume that wood
louvers have a 20 percent free area and metal louvers or grilles
have a 60 percent free area. Screens, when used, must not be
smaller than 1/4-in. mesh. Louvers and grilles must be constructed
so they cannot be closed.
The size of the openings depends upon whether air comes from
outside of the structure or an unconfined space inside the structure.
1. All air from inside the structure requires 2 openings (for
structures not usually tight):
a. Each opening MUST have at least 1 sq in. of free area
per 1000 Btuh of total input for all equipment within the
confined space, but not less than 100 sq in. per opening.
(See Fig. 4 and Table 2.) The minimum dimension of air
openings shall not be less than 3 in.
For Example:
383KAV FURNACE
INPUT BTUH
MINIMUM SQ FT WITH
7-1/2 FT CEILING
44,000
293
66,000
440
88,000
587
110,000
733
132,000
880
154,000
1026
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