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Copper Brute B4 Volume Water Heaters
Mode
175
250
325
400
Note: For screens or louvers, add 50%.
Table 2. Air Openings to Outside.
Vent terminated at
least 24 in.
(610mm) above
any object within
10 ft. (3.0m)
1/14 in. (6mm)
Minimum Pitch
Horizontal Pipe
Notes:
1. The drafthood must sit directly on top of the heater
as shown and must not be altered in any manner.
2. An Underwriters' Laboratories listed vent cap is
quired to eliminate downdraft and allow the heater
to function properly.
3. Use approved roof fitting.
Figure 14. Indoor installation and venting.
In the United States, the most common
requirements specify that the space shall communicate
with the outdoors in accordance with method 1 or 2,
which follow. Where ducts are used, they shall be of
the same cross-sectional area as the free area of the
openings to which they connect.
Method 1:
Two permanent openings, one commencing
within 12" (30 cm) of the top and one commencing
within 12" (30 cm) of the bottom of the enclosure
shall be provided. The openings shall communicate
Required Net Free Opening Area
Directly from Outside
At Top
At Bottom
in.
cm
2
2
44
284
63
406
82
529
100
645
10 ft.
Listed Vent
(3.0m)
2 ft. (0.6m)
Storm Collar
Per Foot of
Drafthood
12 in.
(305mm)
All Sides
directly, or by ducts, with the outdoors or spaces that
freely communicate with the outdoors. When directly
communicating with the outdoors directly, or through
vertical ducts, each opening shall have a minimum
in.
cm
2
2
free area of 1 square inch per 4000 Btu/hr (550 square
mm/kW) of total input rating of all equipment in the
44
284
enclosure. When communicating to the outdoors
63
406
through horizontal ducts, each opening shall have a
82
529
minimum free area of not less than 1 square inch per
100
645
2000 Btu/hr (1100 square mm/kW) of total input rating
of all equipment in the enclosure.
Method 2:
12" (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
Cap
that directly communicate with the outdoors, and shall
have a minimum free area of 1 square inch per 3000
Btu/hr (734 square mm/kW) of the total input rating of
Roof Jack
all equipment located in the enclosure. This opening
must not be less than the sum of the areas of all vent
connectors in the confined space.
ventilation air are acceptable, providing they conform
to the requirements in ANSI Z223.1, or applicable
Adequate
codes.
Air Supply
To Room
Top and
local building and safety codes or, in absence of such
Botom
requirements, follow CAN/CGA B149.
free area of louvers. If screens or louvers are installed,
add 50 percent for each screen/louver to the net free
area Check all local codes applicable to combustion
air.
re-
outside wall, each opening must have a minimum free
area of at least one square inch for each 4,000 BTU/h
input of the total input rating of all appliances in the
enclosed area. (In Canada, refer to CGAB149.1 and .2.)
requirements for installation. Consult the latest edition
of the National Gas Code for installation requirements.
from the heater room can use up the combustion air
supply or reverse the natural draft action of the venting
system. This could cause flue products to build up in
the heater room. More air must be supplied to make up
for the decrease.
One permanent opening, commencing within
Other methods of introducing combustion and
In Canada, Table 2 does not apply. Consult
NOTE: Check with louver manufacturers for net
2.4.1 Outdoor Air Supply
When combustion air comes directly through an
2.4.2 Indoor Air Supply
Confined and non-confined areas have different
2.4.3 Exhaust Fans or Vents
Any equipment which uses air or removes air
Page 7
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