ICP G9MAC Series Installation Instructions Manual page 10

Outdoor Combustion Air Method
1. Provide the space with sufficient air for proper
combustion, ventilation, and dilution of flue gases using
permanent horizontal or vertical duct(s) or opening(s)
directly communicating with the outdoors or spaces that
freely communicate with the outdoors.
2. Figure 6 illustrates how to provide TWO OUTDOOR
OPENINGS, one inlet and one outlet combustion and
ventilation air openings to the outdoors.
a. One opening MUST commence within 12-in.
(300 mm) of the ceiling and the second opening
MUST commence within 12-in. (300 mm) of the floor.
b. Size openings and ducts per Figure 6 and Table 3.
c. TWO HORIZONTAL DUCTS require 1 square inch
(25.4 square mm) of free area per 2,000 Btuh (1,100
2
mm /kW) of combined input for all gas appliances in
the space per Figure 6 and Table 3.
Table 3 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
(BTUH)
Free Area of
Opening and Duct
Sq. In (Sq. mm)
30 (19355)
60,000
40 (25807)
80,000
50 (32258)
100,000
60 (38709)
120,000
70 (45161)
140,000 *
EXAMPLE: Determining Free Area
FURNACE WATER HEATER
100,000 + 30,000
60,000 + 40,000
80,000 + 30,000
Table 4 Minimum Space Volumes for 100% Combustion, Ventilation and Dilution Air from Outdoors
OTHER THAN FAN‐ASSISTED TOTAL
(1,000'S BTUH GAS INPUT RATE)
30
ACH
1,050
0.60
(29.7)
1,260
0.50
(35.6)
1,575
0.40
(44.5)
2,100
0.30
(59.4)
3,150
0.20
(89.1)
6,300
0.10
(178.0)
NP
0.00
NP = Not Permitted
10
Round
Duct
In. (mm)
Dia
6 (152)
7 (178)
8 (203)
9 (229)
10 (254)
TOTAL INPUT
= (130,000 divided by 4,000)
= (100,000 divided by 3,000)
= (110,000 divided by 2,000)
40 50
1,400 1,750
(39.6) (49.5)
1,680 2,100
(47.5) (59.4)
2,100 2,625
(59.4) (74.3)
2,800 3,500
(79.2) (99.1)
4,200 5,250
(118.9) (148.6)
8,400 10,500
(237.8) (297.3)
NP NP
Specifications subject to change without notice.
d. TWO OPENINGS OR VERTICAL DUCTS require 1
square inch (25.4 square mm)of free area per 4,000
Btuh (550 mm
appliances in the space per Figure 6 and Table 3.
3. ONE OUTDOOR OPENING requires:
a. 1 sq. in. (25.4 square mm)of free area per 3,000 Btuh
(734 mm
appliances in the space per Table 3 and
b. Not less than the sum of the areas of all vent
connectors in the space.
The opening shall commence within 12-in. (300 mm) of the
ceiling. Appliances in the space shall have clearances of at
least 1-in. (25 mm) from the sides and back and 6-in. (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.
SINGLE DUCT OR OPENING
(1 SQ. IN./3,000 BTUH)
(734 SQ. MM/KW)
Round
Free Area of Open-
Duct
ing and Duct
In. (mm)
Sq. In (Sq. mm)
Dia
20 (13043) 5 (127)
27 (17391) 6 (152)
34 (21739) 7 (178)
40 (26087) 7 (178)
47 (30435) 8 (203)
= 32.5 Sq. In. for each two Vertical Ducts or Openings
= 33.3 Sq. In. for each Single Duct or Opening
= 55.0 Sq. In. for each two Horizontal Ducts
FAN‐ASSISTED TOTAL
(1,000'S BTUH GAS INPUT RATE)
40 60
3 3
Space Volume Ft (M )
1,400 1,500 2,000
(39.6) (42.5) (56.6)
1,680 1,800 2,400
(47.5) (51.0) (67.9)
2,100 2,250 3,000
(59.4) (63.7) (84.9)
2,800 3,000 4,000
(79.2) (84.9) (113.2)
4,200 4,500 6,000
(118.9) (127.3) (169.8)
8,400 9,000 12,000
(237.8) (254.6) (339.5)
NP NP
2
/kW) for combined input of all gas
2
/kW) for combined input of all gas
TWO OPENINGS OR
VERTICAL DUCTS
(1 SQ. IN./4,000 BTUH)
(550 SQ. MM/KW)
Free Area of Open-
ing and Duct
Sq. In (mm)
15 (9678)
20 (12904)
25 (16130)
30 (19355)
35 (22581)
80 100 120
2,500 3,000
(70.8) (84.9)
3,000 3,600
(84.9) (101.9)
3,750 4,500
(106.1) (127.3)
5,000 6,000
(141.5) (169.8)
7,500 9,000
(212.2) (254.6)
15,000 18,000
(424.4) (509.2)
NP NP NP
Round Duct
In. (mm)
Dia.
5 (127)
5 (127)
6 (152)
6 (152)
7 (178)
140
3,500
(99.1)
4,200
(118.9)
5,250
(148.6)
7,000
(198.1)
10,500
(297.1)
21,000
(594.1)
NP
440 01 4201 03