Bradford-White Corp Water Heater BWCH Manual De Usuario

Page 8

 

 

EACH OPENING*

 

SIZE 

SQUARE INCHES 

 500 

125 

 750 

188 

 1000 

250 

 1250 

313 

 1500 

375 

 1750 

438 

 2000 

500 

*Net Free Area in Square Inches / Square cm

Area indicated is for one of two openings; one at floor level and 
one at the ceiling, so the total net free area could be double the 

figures indicated.
This chart is for use when communicating directly with the 

outdoors. For special conditions and alternate methods, refer to 

the latest edition of ANSI Z223.1.
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.

Copper Brute II boilers and water heaters must 

have provisions for combustion and ventilation air 

in accordance with Section 5.3, Air for Combustion 

and Ventilation, of the National Fuel Gas Code, ANSI 

Z223.1, or Sections 7.2, 7.3 or 7.4 of CSA B149.1, 
Installation Codes, or applicable provisions of the local 

building codes.

A Copper Brute II appliance may receive 

combustion air from the space in which it is installed, 

or it can be ducted directly to the unit from the outside. 

Ventilation air must be provided in either case.

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 inches (30 cm) of the top 

and one commencing within 12 inches (30 cm) of 

the bottom, of the enclosure shall be provided. The 
openings shall communicate directly, or by ducts, 
with the outdoors or spaces that freely communicate 

with the outdoors. When directly communicating 
with the outdoors, or when communicating to the 
outdoors through vertical 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 3

 shows data for this sizing method, for each 

Copper Brute II 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 confined 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.

2.1.2  Intake Combustion Air
The combustion air can be taken through the 

wall, or through the roof. When taken from the wall, 
it must be taken from out-of-doors by means of the 
Bradford White horizontal wall terminal (see 

Table 2

). 

When taken from the roof, a field-supplied rain cap or 
an elbow arrangement must be used to prevent entry of 
rain water (

see Figure 2

).

Use single-wall galvanized pipe, per 

Table 4

, for 

the combustion air intake (see 

Table 2

 for appropriate 

size). Route the intake to the heater as directly as 

possible. Seal all joints with tape. Provide adequate 

hangers. The unit must not support the weight of the 

combustion air intake pipe. Maximum linear pipe