Empire FAW40IPXLP-1, Инструкция по установке и руководство пользователя

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37134-4-0319 Page 5
Ventilation and combustion Air
WArNING: Danger of property damage, bodily injury or death,
this furnace and any other fuel burning appliance must be
provided with enough fresh air for proper combustion and
ventilation of flue gases. Most homes will require that outside
air be supplied. Do not draw air from a corrosive environment
such as a workshop or laundry room.
The requirements for providing air for combustion and ventilation
are listed in the National Fuel Gas codes NFPA 54/ANSI Z223.1
(in canada - cAN/cGA B149).
Note: Air requirements for operation of exhaust fans, kitchen
ventilation systems, clothes dryers, fireplace and any other fuel
burning or ventilating equipment used in the space must be
considered in determining combustion air requirements.
Ventilation Air openings and Ducts
In determining the free area needed consideration must be given to
the blocking effect of louvers, grills or screens protecting openings.
— If a screen is used to cover openings it must not be smaller than
1/4" mesh.
— Use the free area of a louver or grill to determine the size opening
required to provide the free area specified. If the free area is not
known assume a 20% free area for wood and a 60% free area
for a metal louver or grill.
— Ducts must have the same cross sectional area as the free area
of the openings to which they connect.
— The minimum dimension of air ducts must not be less than 3
inches.
Installation in an Unconfined Space
An unconfined space is an area including all rooms not separated by
doors with a volume greater than 50 cubic feet per 1,000 Btuh of the
combined total input rates of all appliances which draw combustion
air from that space. For example, a space including a water heater
rated at 40,000 Btuh input and a furnace rated at 40,000 Btuh
requires a volume of 4,000 cubic feet (50 x (40 + 40) = 4,000) to be
considered as unconfined. If the space has an 8 ft. ceiling, the floor
area of the space must be 500 sq. ft. In general, particularly in older
homes, a furnace installed in an unconfined space will not require
outside air for combustion. However in a "tight" newly constructed
home, outside air may be necessary to insure adequate combustion.
Installation in a Confined Space
A confined space is an area with volume less than 50 cubic feet per
1,000 Btuh of the combined input rates of all appliances drawing
combustion air from that space. Small areas such as equipment
rooms are confined spaces. Furnaces installed in a confined space
which supply heated air to areas outside the space must draw return
air from outside the space through tightly sealed return air ducts. A
confined space must have 2 openings into the space for combustion
air. One opening must be within 12 inches of the ceiling and the
other must be within 12 inches of the floor. The required sizing of
these openings is determined by whether inside or outside air is
used to support combustion, the method by which the air is brought
to the space (vertical or horizontal duct) and by the total input rate
of all appliances in the space. See Figure 1.
All Air From Inside — Confined Space
If combustion air is taken from the heated space the 2 openings
must each have a free area of at least one square inch per 1,000
Btuh of total input of all appliances in the confined space but not
less than 100 square inches (645cm
2
) of free area.
For example: for a 40,000 Btuh furnace only in the confined space
each opening must be 100 square inches (645cm
2
) each of free area.
WArNING: combustion air must not be drawn from a heated
space which includes exhaust fans, fireplaces or other devices
that may produce a negative pressure in the space.
furnace
opening
confined
space
Figure 1
outdoor Air
Outlet and inlet air can be brought into the confined space via
openings into a ventilated attic and ventilated crawl space.
furnace
outlet air
inlet air
attic ventilation louvers
crawl space ventilation louvers
Figure 2
Confined Space
outdoor Air Using Vertical or Horizontal Ducts
If combustion air is taken from outdoors through vertical ducts, the
openings and ducts must have a minimum free area of one square
inch (6.5cm
2
) per 4,000 Btuh of total appliance input. In installations
drawing combustion air from a ventilated attic both air ducts must
extend above the attic insulation.
furnace
outlet air
inlet air ends one foot above floor
vertical
furnace
inlet air duct
outlet air duct
horizontal
Figure 3
If combustion air is taken from outdoors through horizontal ducts the
openings and ducts must have a minimum free area of one square
inch (6.5cm
2
) per 2,000 Btuh of total appliance input.