Air For Combustion And Ventilation - Carrier 58MCB Installation, Start-Up, And Operating Instructions Manual

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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
NON-DIRECT VENT (1-PIPE) APPLICATION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in intermittent unit
operation.
Do not install furnace in a corrosive or contaminated atmo-
sphere. Make sure all combustion and circulating air require-
ments are met.
Refer to the AIR FOR COMBUSTION AND VENTILATION
section for details.

AIR FOR COMBUSTION AND VENTILATION

Provisions for adequate combustion, ventilation, and dilution air
must be provided in accordance with:
• U.S. Installations: Section 8.3 of the NFGC, Air for Combus-
tion and Ventilation and applicable provisions of the local
building codes.
• Canadian Installations: Part 7 of the NSCNGPIC, Venting
Systems and Air Supply for Appliances and all authorities
having jurisdiction.
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
(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
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FURNACE CORROSION HAZARD
Failure to follow this warning could result in reduced furnace
component life.
Air for combustion must not be contaminated by halogen
compounds, which include fluoride, chloride, bromide, and
iodide. These elements could corrode heat exchangers and
shorten furnace life. Air contaminants are found in aerosol
sprays, detergents, bleaches, cleaning solvents, salts, air
fresheners, and other household products.
The following types of furnace installations may require OUT-
DOOR AIR for combustion due to chemical exposures:
• Commercial buildings
• Buildings with indoor pools
• Laundry rooms
• Hobby or craft rooms, and
• Chemical storage areas
If air is exposed to the following substances, it should not be used
for combustion air, and outdoor air may be required for combus-
tion:
• Permanent wave solutions
• Chlorinated waxes and cleaners
• Chlorine based swimming pool chemicals
• Water softening chemicals
16
TWO OPENINGS OR VERTICAL DUCTS
(1 SQ. IN./4,000 BTUH) (550 SQ. MM/KW)
Free Area of
Opening and Duct
(in. Dia)
(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
2,200 2,750
2,640 3,300
3,300 4,125
4,400 5,500
6,600 8,250
13,200 16,500 19,800
NP NP
Round Duct
(In. Dia)
4
5
6
6
7
8
132 154
3,300 3,850
3,960 4,620
4,950 5,775
6,600 7,700
9,900 11,550
23,100
NP NP