Carrier 58MVP Installation, Start-Up, And Operating Instructions Manual page 14

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
EXAMPLES: Determining Free Area
FURNACE WATER HEATER
110,000 + 30,000
66,000 + 40,000
88,000 + 30,000
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
Indoor Combustion Air© NFPA & AGA
Standard and Known-Air-Infiltration Rate Methods
Indoor air is permitted for combustion, ventilation, and dilution,
if the Standard or Known-Air-Infiltration 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).
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.
(1 SQ. IN./3,000 BTUH) (734 SQ. MM/KW)
Round Duct
Opening and Duct
(in. Dia)
6
7
8
9
10
10
TOTAL INPUT
= (140,000 divided by 4,000)
= (106,000 divided by 3,000)
= (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
Free Area of
Round Duct
(in. Dia)
(sq In.)
14.7 5
22 6
29.3 7
36.7 7
44 8
51.3 9
= 35.0 Sq. In. for each two Vertical Ducts or Openings
= 35.3 Sq. In. for a Single Duct or Opening
= 59.0 Sq. In. for each of two Horizontal Ducts
FAN-ASSISTED TOTAL
(1,000'S BTUH GAS INPUT RATE)
44 66
Space Volume (ft 3 )
1,100 1,650 2,200
1,320 1,980 2,640
1,650 2,475 3,300
2,200 3,300 4,400
3,300 4,950 6,600
6,600 9,900 13,200
NP NP
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:
Volume
2. For fan-assisted appliances such as this furnace:
Volume
If:
I = combined input of all other than fan-assisted appli-
other
ances in Btu/hr
= combined input of all fan-assisted appliances in Btu/hr
I
fan
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.
of the total input rating of all gas appliances in the space,
14
TWO OPENINGS OR VERTICAL DUCTS
(1 SQ. IN./4,000 BTUH) (550 SQ. MM/KW)
Free Area of
Opening and Duct
(Sq In.)
11
16.5
22
27.5
33
38.5
88 110 132
2,750 3,300
3,300 3,960
4,125 4,950
5,500 6,600
8,250 9,900
16,500 19,800
NP NP NP
I
= 21ft
3
other
ACH 1000 Btu/hr
Other
I
= 15ft
3
fan
ACH 1000 Btu/hr
Fan
2
/1,000 Btuh (2,000 mm
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
2
/kW)