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Combustion air supply & ventilation, Confined space, All air from inside the building – Kenmore 153:331472 User Manual

Page 16: Combustion air supply & ventilation -19, Unconfined space, All air from inside the building -17, Awarning

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COMBUSTION AIR SUPPLY & VENTILATION

AWARNING

Carbon Monoxide Warning

Follow all the local and state codes or, In the absence of

local and state codes, the “National Fuel Gas Code”,

ANSI

Z223.1

(NFPA

54)-

current

edition

to

properly

Install vent system.

Failure

to

do

so

can

result

In

death,

explosion,

or

carbon monoxide poisoning.

IMPORTANT: Air for combustion and ventilation must not

come from a corrosive atmosphere. Any failure due to corrosive

elements in the atmosphere is excluded from warranty

coverage.

The following types of installation (not limited to the following)

will require outdoor air for combustion due to chemical exposure

and may reduce but not eliminate the presence of corrosive

chemicals in the air:

• beauty shops

• photo processing labs

• buildings with indoor pools

• water heaters installed in laundry, hobby, or craft rooms

• water heaters installed near chemical storage areas

Combustion air must be free of acid-forming chemicals such as sulfur,

fluorine, and chlorine. These elements are found in aerosol sprays,

detergents, bleaches, cleaning solvents, air fresheners, paint, and

varnish removers, refrigerants, and many other commercial and

household products. When burned, vapors from these products

form highly corrosive acid compounds. These products should not

be stored or used near the water heater or air inlet.

Combustion and ventilation air requirements are determined by

the location of the water heater. The water heater may be located

in either an open (unconfined) area or in a confined area or small

enclosure such as a closet or small room. Confined spaces are

areas with less than 50 cubic feet for each 1,000 BTUH of the total

input for all gas-using appliances.

Unconfined Space

A water heater in an unconfined space uses indoor air for

combustion and requires at least 50 cubic feet for each 1,000

BTUH of the total input for all gas appliances. The table below

shows a few examples of the minimum square footage (area)

required for various BTUH inputs.

TABLE 3

BTUH Input

Minimum Square

Feet with

8

’ Ceiling

Typical

Room

with 8’ Ceiling

30,000

188

9x21

45,000

281

14 x20

60,000

375

15 x25

75,000

469

15

X

31

90,000

563

20 x28

105,000

657

20

X

33

TABLE 3

120,000

750

25

X

30

135,000

844

28

X

30

IMPORTANT:

• The area must be open and be able to provide the proper

air requirements to the water heater. Areas that are being

used for storage or contain large objects may not be

suitable for water heater installation.

• Water heaters installed in open spaces in buildings with

unusually tight construction may still require outdoor air

to function properly. In this situation, outside air openings

should be sized the same as for a confined space.

requires supplying

• Modern home construction usually

outside air into the water heater area.

Confined Space

For the correct and proper operation of this water heater,

ample air must be supplied for the combustion, ventilation, and

dilution of flue gases. Small enclosures and confined areas

must have two permanent openings so that sufficient fresh air

can be drawn from outside of the enclosure. One opening shall

be within 12 inches of the top and one within 12 inches of the

bottom of the enclosure as shown in Figure 12.
The size of each opening (free area) is determined by the total

BTUH input of all gas utilization equipment (i.e., water heaters,

furnaces, clothes dryers, etc.) and the method by which the air

is provided. The BTUH input can be found on the water heater

rating plate. Additional air can be provided by two methods:

1. All air from inside the building.

2. All air from outdoors.

12” MAXIMUM

PERMANENT

OPENINGS TO

THE OUTSIDE OR

ADDITIONAL

ROOMS WITHIN

THE BUILDING

12” MAXIMUM

CLOSET

. OR

OTHER

CONFINED

SPACE

3=^

FIGURE 12.

All Air from Inside the Building______________

When additional air is to be provided to the confined area

from additional room(s) within the building, the total volume of

the room(s) must be of sufficient size to properly provide the

necessary amount of fresh air to the water heater and other

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