Location Relative To Cooling Equipment; Hazardous Locations; Air For Combustion And Ventilation; Unconfined Space - Carrier 58GFA Installation, Starting-Up And Operation Manual

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
will 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 mate-
rials, and many other solvents commonly used in the con-
struction process.
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. Locate the furnace close to the chimney/vent
and as near the center of the air distribution system as possible.
The furnace should be installed level.
When a furnace is installed so that the supply ducts carry air to
areas outside the space containing the furnace, the return air must
also be handled by a duct(s) sealed to the furnace casing and
terminating outside the space containing the furnace.
Provide ample space for servicing and cleaning. Always comply
with the minimum fire protection clearances shown on the unit
rating plate. This furnace shall not be installed directly on
carpeting, tile, or any combustible material other than wood
flooring.
LOCATION RELATIVE TO COOLING EQUIPMENT — The
cooling coil must be installed parallel with or on the downstream
side of the furnace 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.
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.
Step 2—Air for Combustion and Ventilation
Provisions for adequate combustion and ventilation air must be
provided in accordance with Section 5.3, Air for Combustion and
Ventilation, of the NFGC or applicable provisions of the local
building codes.
Canadian installations must be in accordance with NSCNGPIC.
Air for combustion must not be contaminated by halogen
compounds, which include fluoride, chloride, bromide, and
iodide. These elements are found in aerosol sprays, deter-
gents, 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 air from being pulled
from the burner area and draft safeguard opening.
The operation of exhaust fans, kitchen ventilation fans,
clothes dryers, or fireplaces could create a NEGATIVE
PRESSURE condition at the furnace. Makeup air MUST be
provided for the ventilation devices, in addition to that
required by the furnace.
Combustion air requirements are determined by whether the
furnace is in an UNCONFINED or CONFINED space.
UNCONFINED SPACE — An unconfined space must have at
least 50 cu ft for each 1000 Btuh of input for all the appliances
(such as furnaces, clothes dryer, water heaters, etc.) in the space.
For Example:
58GFA FURNACE
INPUT BTUH
63,000
84,000
105,000
126,000
147,000
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. A minimum opening with a total of not less than 1 sq in. per
5000 Btuh of total input rating for all equipment must be provided.
Return air must not be taken from the room unless an equal or
greater amount of air is supplied to the room.
CONFINED SPACE — A confined space is one whose volume is
less than 50 cu ft per 1000 Btuh of the total output rating for all
appliances installed in that space. A confined space MUST have 2
permanent openings, 1 within 12 in. of the ceiling, and the other
within 12 in. of the floor. (See Fig. 2.)
NOTE: In determining the free area of an opening, the blocking
effect of the louvers, grilles, and screens must be considered. If the
free area of a louver or grille design is unknown, it may be
assumed 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 the air comes from
inside or outside of the structure.
1. All air from inside the structure:
Each opening MUST have at least 1 sq in. of free area per
1000 Btuh of the total input for all equipment within the
confined space, but not less than 100 sq in. per opening. (See
Fig. 2.)
For Example:
58GFA FURNACE
INPUT BTUH
63,000
84,000
105,000
126,000
147,000
If the building is constructed unusually tight, a permanent opening
directly communicating with the outdoors should be provided.
This opening shall have a minimum free area of 1 sq in. per 5000
Btuh of total input rating for all equipment in the enclosure.
3
MINIMUM SQ FT
WITH
7-1/2 FT CEILING
420
560
700
840
980
FREE AREA PER
OPENING (SQ IN.)
100
100
105
126
147