Hazardous Locations; Air For Combustion And Ventilation; General; Unconfined Space - Carrier 58MSA Installation, Start-Up, And Operating Instructions Manual

FRONT
BACK
FRONT
Fig. 14—Prohibit Installation on Back
If this furnace is installed in a n unconditioned space where
ambient temperatures may be 32°F or lower, freeze protection
measures must be taken. (See Fig. 15.) Failure to follow this
caution will result in minor property or unit damage.
32°F MINIMUM INSTALLED
AMBIENT OR FREEZE
PROTECTION REQUIRED
Fig. 15—Freeze Protection
Step 3—Hazardous Locations
When the furnace is installed in a residential garage, the
burners and ignition sources must be located at least 18 in.
above the floor. The furnace must be located or protected to
avoid physical damage by vehicles. When the furnace is
installed in a public garage, airplane hangar, or other building
having a hazardous atmosphere, the furnace must be installed
in accordance with the NFGC or NSCNGPIC. (See Fig. 16.)

AIR FOR COMBUSTION AND VENTILATION

Step 1—General
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.
B
A
C
K
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Canadian installations must be in accordance with Section 7.2 of
the Air Supply Determination for Central Heating Furnaces,
Boilers, and Hot Water Heaters, and 7.3, Air Supply Openings and
Ducts, of the NSCNGPIC and all authorities having jurisdiction.
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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. Failure to follow this caution will
result in minor unit damage.
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 draft safeguard opening into the circulating air.
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The operation of exhaust fans, kitchen ventilation fans,
clothes dryers, fireplaces, or other appliances including attic
and crawlspace exhaust fans could create a negative air
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pressure condition at the furnace. Make-up air must be
provided for these devices, in addition to that required by the
furnace. Failure to follow this caution will result in minor unit
operation or performance satisfaction.
The requirements for combustion and ventilation air depend upon
whether the furnace is located in a CONFINED or UNCONFINED
space.
Step 2—Unconfined Space
An unconfined space must have at least 50 cu ft for each 1000
Btuh of total input for all the appliances (such as furnaces, clothes
dryers, 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.
14
18-IN. MINIMUM
TO BURNERS
Fig. 16—Installation in a Garage
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