Volume, 21ft, Ach i – Bryant 2-stage Deluxe Induced-Combustion 4-way Multipurpose 120 User Manual

Page 10: 1000 btu/hr, 15ft, Installation

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Table 3 – Minimum Space Volumes for 100% Combustion, Ventilation, and Dilution from Indoors

ACH

OTHER THAN FAN---ASSISTED TOTAL

(1,000s BTUH GAS INPUT RATE)

FAN---ASSISTED TOTAL

(1,000s BTUH GAS INPUT RATE)

30

40

50

44

66

88

110

132

154

Space Volume (ft 3)

0.60

1,050

1,400

1,750

1,100

1,650

2,200

2,750

3,300

3,850

0.50

1,260

1,680

2,100

1,320

1,980

2,640

3,300

3,960

4,620

0.40

1,575

2,100

2,625

1,650

2,475

3,300

4,125

4,950

5,775

0.30

2,100

2,800

3,500

2,200

3,300

4,400

5,500

6,600

7,700

0.20

3,150

4,200

5,250

3,300

4,950

6,600

8,250

9,900

11,550

0.10

6,300

8,400

10,500

6,600

9,900

13,200

16,500

19,800

23,100

0.00

NP

NP

NP

NP

NP

NP

NP

NP

NP

NP = Not Permitted

Table 3--Minimum Space Volumes were determined by using
the following equations from the National Fuel Gas Code ANSI

Z223.1--2006/NFPA 54--2006, 9.3.2.2:

1. For other than fan--assisted appliances, such as a draft

hood--equipped water heater:

Volume

Other

= 21ft

3

ACH

I

other

1000 Btu/hr

A04002

2. For fan--assisted applicances such as this furnace:

Volume

Fan

= 15ft

3

ACH

I

fan

1000 Btu/hr

A04003

If:
I

other

= combined input of all other than fan--assisted

appliances in Btuh/hr

I

fan

= combined input of all fan--assisted appliances in

Btuh/hr

ACH = air changes per hour (ACH shall not exceed 0.60.)

The following requirements apply to the Standard Method and
to the Known Air Infiltration Rate Method.

1. Adjoining rooms can be considered part of a space if:

a. There are no closable doors between rooms.

b. Combining spaces on same floor level. Each opening

shall have free area of at least 1 in.2/1,000 Btuh (2,000
mm2/kW) of the total input rating of all gas appliances

in the space, but not less than 100 in.2 (0.06 m2). One
opening shall commence within 12 in. (300 mm) of the

ceiling and the second opening shall commence within
12 in. (300 mm) of the floor. The minimum dimension

of air openings shall be at least 3 in. (80 mm). (See Fig.
8.)

c. Combining space on different floor levels. The volumes

of spaces on different floor levels shall be considered as
communicating spaces if connected by one or more

permanent openings in doors or floors having free area
of at least 2 in.2/1,000 Btuh (4,400 mm2/kW) of total
input rating of all gas appliances.

2. An attic or crawlspace may be considered a space that

freely communicates with the outdoors provided there are

adequate permanent ventilation openings directly to
outdoors having free area of at least 1--in.2/4,000 Btuh of
total input rating for all gas appliances in the space.

3. In spaces that use the Indoor Combustion Air Method,

infiltration should be adequate to provide air for

combustion, permanent ventilation and dilution of flue
gases. However, in buildings with unusually tight

construction, additional air MUST be provided using the
methods described in the Outdoor Combustion Air

Method section. Unusually tight construction is defined as
Construction with:

a. Walls and ceilings exposed to the outdoors have a

continuous, sealed vapor barrier. Openings are gasketed
or sealed and

b. Doors and openable windows are weatherstripped and

c. Other openings are caulked or sealed. These include

joints around window and door frames, between sole

plates and floors, between wall--ceiling joints, between
wall panels, at penetrations for plumbing, electrical and

gas lines, etc.

Combination of Indoor and Outdoor Air

1. Indoor openings shall compy with the Indoor

Combustion Air Method below and,

2. Outdoor openings shall be located as required in the

Outdoor Combustion Air Method mentioned previously
and,

3. Outdoor openings shall be sized as follows:

a. Calculate the Ratio of all Indoor Space volume divided

by required volume for Indoor Combustion Air

Method below.

b. Outdoor opening size reduction Factor is 1 minus the

Ratio in a. above.

c. Minimum size of Outdoor openings shall be the size

required in Outdoor Combustion Air Method above

multiplied by reduction Factor in b. above. The
minimum dimension of air openings shall be not less than

3 in. (80 mm).

INSTALLATION

UPFLOW INSTALLATION
Bottom Return Air Inlet
These furnaces are shipped with bottom closure panel installed in
bottom return--air opening. Remove and discard this panel when

bottom return air is used. To remove bottom closure panel,
perform the following:

1. Tilt or raise furnace and remove 2 screws holding bottom

filler panel. (See Fig. 9.)

2. Rotate bottom filler panel downward to release holding

tabs.

3. Remove bottom closure panel.
4. Reinstall bottom filler panel and screws.

Side Return Air Inlet
These furnaces are shipped with bottom closure panel installed in
bottom return--air opening. This panel MUST be in place when

only side return air is used.
NOTE: Side return--air openings can be used in UPFLOW and
most HORIZONTAL configurations. Do not use side return--air
openings in DOWNFLOW configuration.

312A

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