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BRADFORD WHITE
Page 6
B4 Volume Water Heater Page 7
ducts, each opening shall have a minimum free
area of 1 square inch per 4000 Btu/hr (5.5 square
cm/kW) of total input rating of all equipment
in the enclosure. When communicating to the
outdoors through horizontal ducts, each opening
shall have a minimum free area of not less than
1 square inch per 2000 Btu/hr (11 square cm/
kW) of total input rating of all equipment in the
enclosure. Table 2 shows data for this sizing
method, for each Copper Brute model.
Method 2: One permanent opening,
commencing within 12 inches (30 cm) of the
top of the enclosure, shall be permitted. The
opening shall directly communicate with the
outdoors or shall communicate through a vertical
or horizontal duct to the outdoors or spaces that
directly communicate with the outdoors and shall
have a minimum free area of 1 square inch per
3000 Btu/hr (7 square cm/kW) of the total input
rating of all equipment located in the enclosure.
This opening must not be less than the sum of the
areas of all vent connectors in the conned space.
Other methods of introducing combustion
and ventilation air are acceptable, providing they
conform to the requirements in the applicable
codes listed above.
In Canada, consult local building and safety
codes or, in absence of such requirements, follow
CSA B149.1.
IMPORTANT: In beauty shops, barber shops,
cleaning establishments and self-service laundries with
dry cleaning equipment, it is important that the water
heater be installed in a location where combustion and
ventilation air is received from a source outside the
building. Please refer to the most recent edition of the
National Fuel Gas Code, ANSI Z223.1, or in Canada,
CSA requirements.
3. (a) In the United States: Exhaust Fans or
Vents: Any equipment which exhausts air from
the heater room can deplete the combustion air
supply or reverse the natural draft action of the
venting system. This could cause ue products
to accumulate in the heater room. Additional air
must be supplied to compensate for such exhaust.
The information in Table 2 is not applicable in
installations where exhaust fans or blowers of
any type are used. Such installations must be
designed by qualied engineers.
(b) In Canada: Follow Canadian standard, CSA
B149.1 or local codes.
4. If a blower or fan is used to supply air to the
heater room, the installer should make sure it
does not create drafts which could cause nuisance
shutdowns of the pilot. If a blower is necessary to
provide adequate combustion air to the heater, a
suitable switch or equivalent must be wired into
the heater control circuit to prevent the heater
from ring unless the blower is operating.
5. The heater must be completely isolated and
protected from any source of corrosive chemical
fumes such as trichlorethylene, perchlorethylene,
chlorine, etc.
2.2.2 Venting
1. Bradford White heaters have built-in draft
diverters for natural draft operation and must not
be connected to any portion of a mechanical draft
system under positive pressure. The ue outlet
must be connected to a clear, unobstructed vent
of adequate capacity ending above the highest
point of the building with an approved vent cap.
The venting system should be installed according
to the latest edition of ANSI Z223.1 and/or, in
Canada, CSA B149.1 requirement and any local
codes having jurisdiction.
IMPORTANT NOTE: Do not use sheet metal
screws at the snap lock joints of Type B gas
vents.
2. Do not weld or fasten the vent pipe to the heater
draft hood. The weight of the stack must not rest
on the heater. The draft hood and heater top must
be easily removable for normal heater service
and inspection.
Table 2. Minimum Recommended
Air Supply to heater.
Heater Each Opening*
Model (Square Inches)
500 125
600 150
715 179
850 213
1010 253
1200 300
1430 358
1670 418
1825 457
*Net Free Area in Square Inches
Area indicated is for one of two openings; one at
oor level and one at the ceiling, so the total net
free area could be double the gures indicated.
For special conditions refer to the latest edition of
ANSI Z223.1. or CSA B149.1
Consult factory if not communicating directly
through the walls with the outdoors.
Note: Check with louver manufacturers for
net free area of louvers. Correct for screen
resistance to the net free area if a screen is
installed. Check all local codes applicable to
combustion air.