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Installation & Service Manual
12
TABLE - 1B
MINIMUM RECOMMENDED COMBUSTION
AIR SUPPLY TO EQUIPMENT ROOM
Input
Btu/hr
*Outside Air from
2 Openings Directly from
Outdoors
*Outside Air from
1 Opening Directly
from Outdoors, in
2
*Outside Air from
2 Ducts Delivered from
Outdoors
**Inside Air from
2 Ducts Delivered from
Interior Space
To p
Opening, in
2
Bottom
Opening, in
2
To p
Opening, in
2
Bottom
Opening, in
2
To p
Opening, in
2
Bottom
Opening, in
2
45,000
12
(78 cm
2
)
12
(78 cm
2
)
15
(97 cm
2
)
23
(149 cm
2
)
23
(149 cm
2
)
100
(646 cm
2
)
100
(646 cm
2
)
75,000
19
(123 cm
2
)
19
(123 cm
2
)
25
(162 cm
2
)
38
(246 cm
2
)
38
(246 cm
2
)
100
(646 cm
2
)
100
(646 cm
2
)
90,000
23
(148 cm
2
)
23
(148 cm
2
)
30
(194 cm
2
)
45
(291 cm
2
)
45
(291 cm
2
)
100
(646 cm
2
)
100
(646 cm
2
)
135,000
34
(220 cm
2
)
34
(220 cm
2
)
45
(291 cm
2
)
68
(439 cm
2
)
68
(439 cm
2
)
135
(871 cm
2
)
135
(871 cm
2
)
180,000
45
(291 cm
2
)
45
(291 cm
2
)
60
(388 cm
2
)
90
(581 cm
2
)
90
(581 cm
2
)
180
(1,162 cm
2
)
180
(1,162 cm
2
)
215,000
54
(349 cm
2
)
54
(349 cm
2
)
72
(465 cm
2
)
108
(697 cm
2
)
108
(697 cm
2
)
215
(1,388 cm
2
)
215
(1,388 cm
2
)
260,000
65
(420 cm
2
)
65
(420 cm
2
)
87
(562 cm
2
)
130
(839 cm
2
)
130
(839 cm
2
)
260
(1,678 cm
2
)
260
(1,678 cm
2
)
*Outside air openings shall directly communicate with the outdoors. When combustion air is drawn from the outside through a
duct, the net free area of each of the two openings must have twice (2 times) the free area required for Outside Air/2 Openings.
The above requirements are for the boiler only; additional gas fired appliances in the equipment room will require an increase in
the net free area to supply adequate combustion air for all appliances.
**Combined interior space must be 50 cubic feet per 1,000 Btu/hr input. Buildings MUST NOT be of *“Tight Construction”.
For buildings of *“Tight Construction”, provide air openings into the building from outside.
*No combustion air openings are needed when the water heater is installed in a space with a volume NO LESS than 50 cubic feet
per 1,000 Btu/hr of all installed gas fired appliances. Buildings MUST NOT be of *“Tight Construction”.
*”Tight Construction” is defined as a building with less than 0.40 ACH (air changes per hour).
The distance of the vent terminal from adjacent
build ings, windows that open and building open ings MUST
comply with the latest edition of the National Fuel Gas Code,
ANSI Z223.1, in Canada, the latest edition of CGA Standard
B149 In stal la tion Code for Gas Burn ing Appliances and Equip -
ment.
Vent connection is made directly to the top of the
ap pli ance. This appliance is designed with a built-in draft
diverter. No additional external draft hood is re quired. The
connection from the appliance vent to the common vent or
chimney must be made as direct as possible.
Vent installations for connection to gas vents or
chimneys must be in accordance with “Vent ing of
Equipment,” of the latest edition of the Na tion al Fuel Gas
Code, ANSI Z223.1, in Canada, the latest edi tion of CGA
Standard B149 Installation Code for Gas Burning Appliances
and Equipment or applicable pro vi sions of the local building
codes.
Adequate combustion and ventilation air must be
sup plied to the room where the appliance is installed in
accordance with the latest edition of the National Fuel Gas
Code, ANSI Z223.1, in Canada, the latest edition of CGA
Stan dard B149 Installation Code for Gas Burning Ap pli anc es
and Equipment, or applicable pro vi sions of the local building
codes.
1 Determine boiler location