Carrier Series 100 Installation, Start-Up, And Operating Instructions Manual page 17

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Table 1—Minimum Free Area Required for Each Combustion Air Opening or Duct to Outdoors
TWO HORIZONTAL DUCTS
(1 SQ. IN./2,000 BTUH) (1,100 SQ. MM/KW)
FURNACE
INPUT
Free Area of
(BTUH)
Opening and Duct
(Sq. In.)
44,000 22
66,000 33
88,000 44
110,000 55
132,000 66
154,000 77
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EXAMPLES: Determining Free Area
FURNACE WATER HEATER
110,000 +
66,000 +
88,000 +
→ Table 2—Minimum Space Volumes for 100% Combustion, Ventilation and Dilution Air from Outdoors
OTHER THAN FAN-ASSISTED TOTAL
(1,000'S BTUH GAS INPUT RATE)
ACH
30
0.60 1,050
0.50 1,260
0.40 1,575
0.30 2,100
0.20 3,150
0.10 6,300
0.00 NP
b. Not less than the sum of the areas of all vent connectors in
the space.
The opening shall commence within 12" (300 mm) of the
ceiling. Appliances in the space shall have clearances of at
least 1" (25 mm) from the sides and back and 6" (150 mm)
from the front. The opening shall directly communicate
with the outdoors or shall communicate through a vertical
or horizontal duct to the outdoors or spaces (crawl or attic)
that freely communicate with the outdoors.
Indoor Combustion Air© NFPA & AGA
Standard and Known-Air-Infiltration Rate Methods
Indoor combustion air is permitted for combustion, ventilation,
and dilution, if the Standard or Known-Air-Infiltration Rate
Method is used.
CARBON MONOXIDE POISONING HAZARD
Failure to supply outdoor air via grilles or ducts could result
in death and/or personal injury.
Many homes require air to be supplied from outdoors for
furnace combustion, ventilation, and dilution of flue gases.
The furnace combustion air supply must be provided in
accordance with this instruction manual.
The Standard Method:
1. The space has no less volume than 50 cubic feet per 1,000
Btuh of the maximum input ratings for all gas appliances
installed in the space and
2. The air infiltration rate is not known to be less than 0.40 air
changes per hour (ACH).
Round Duct
(in. Dia)
6
7
8
9
10
10
TOTAL INPUT
30,000 = (140,000 divided by 4,000)
40,000 = (106,000 divided by 3,000)
30,000 = (118,000 divided by 2,000)
40 50
1,400 1,750
1,680 2,100
2,100 2,625
2,800 3,500
4,200 5,250
8,400 10,500
NP NP
SINGLE DUCT OR OPENING
(1 SQ. IN./3,000 BTUH) (734 SQ. MM/KW)
Free Area of
Round Duct
Opening and Duct
(in. Dia)
(sq In.)
14.7
22
29.3
36.7
44
51.3
= 35.0 Sq. In. for each two Vertical Ducts or Openings
=
=
(1,000'S BTUH GAS INPUT RATE)
44 66
3
Space Volume (ft )
1,100 1,650
1,320 1,980
1,650 2,475
2,200 3,300
3,300 4,950
6,600 9,900
NP NP
The Known Air Infiltration Rate Method shall be used, if the
infiltration rate is known to be:
1. Less than 0.40 ACH and
2. Equal to or greater than 0.10 ACH
Infiltration rates greater than 0.60 ACH shall not be used. The
minimum required volume of the space varies with the number of
ACH and shall be determined per Table 2 or Equations 1 and 2.
Determine the minimum required volume for each appliance in the
space and add the volumes together to get the total minimum
required volume for the space.
Table 2-Minimum Space Volumes were determined by using the
following equations from the National Fuel Gas Code ANSI
Z223.1-2002/NFPA 54-2002,8.3.2.2:
1. For other than fan-assisted appliances, such as a draft
hood-equipped water heater:
2. For fan-assisted appliances such as this furnace:
17
TWO OPENINGS OR VERTICAL DUCTS
(1 SQ. IN./4,000 BTUH) (550 SQ. MM/KW)
Free Area of
Opening and Duct
(Sq In.)
5 11
6 16.5
7 22
7 27.5
8 33
9 38.5
35.3 Sq. In. for a Single Duct or Opening
59.0 Sq. In. for each of two Horizontal Ducts
FAN-ASSISTED TOTAL
88 110 132
2,200 2,750 3,300
2,640 3,300 3,960
3,300 4,125 4,950
4,400 5,500 6,600
6,600 8,250 9,900
13,200 16,500 19,800
NP NP NP
I
= 21ft 3
other
Volume
ACH 1000 Btu/hr
Other
I
= 15ft 3
fan
Volume
ACH 1000 Btu/hr
Fan
Round Duct
(In. Dia)
4
5
6
6
7
8
154
3,850
4,620
5,775
7,700
11,550
23,100
NP
A04002
A04003