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1
Determine unit location
Figure 1-6_Outside Combustion Air Through Ducts
4. Outside Combustion Air - Using Direct Venting
With this option, you can connect combustion air vent piping
directly to the unit. See the information under Direct Venting
starting on page 27 for specific information regarding this
option.
*Outside Air from
2 Openings Directly from
Model
Outdoors
Number
Top
Opening, in
2
100
400
(645 cm
)
2
125
500
(806 cm
2
)
163
650
(1052 cm
2
)
188
750
(1213 cm
2
)
248
1000
(1600 cm
2
)
315
1250
(2032cm
)
2
360
1450
(2323cm
)
2
450
1800
(2903cm
2
)
518
2100
(3342cm
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 water heater 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.
12
IMG00582
MINIMUM RECOMMENDED COMBUSTION
AIR SUPPLY TO EQUIPMENT ROOM
*Outside Air from
1 Opening Directly
Bottom
from Outdoors, in
Opening, in
2
100
133
(645 cm
)
(858 cm
2
125
167
(806 cm
2
)
(1077 cm
163
217
(1052 cm
2
)
(1400 cm
188
250
(1213 cm
2
)
(1613 cm
248
330
(1600 cm
2
)
(2129 cm
315
420
(2032cm
)
(2710 cm
2
360
480
(2323cm
)
(3097 cm
2
450
600
(2903cm
2
)
(3871 cm
518
690
(3342cm
2
)
(4452 cm
All dimensions are based on net free area in square inches.
Metal louvers or screens reduce the free area of a combustion air
opening a minimum of approximately 25%. Check with louver
manufacturers for exact net free area of louvers. Where two
openings are provided, one must be within 12" (30 cm) of the
ceiling and one must be within 12" (30 cm) of the floor of the
equipment room. Each opening must have a minimum net free
area as specified in TABLE 1B. Single openings shall be installed
within 12" (30 cm) of the ceiling.
CAUTION
TABLE - 1B
Inside Air from
2 Ducts Delivered from
Outdoors
Top
2
Opening, in
2
Opening, in
200
)
(1291 cm
)
(1291 cm
2
2
250
2
)
(1613 cm
2
)
(1613 cm
325
2
)
(2097 cm
2
)
(2097 cm
375
2
)
(2420 cm
2
)
(2420 cm
495
2
)
(3194 cm
2
)
(3194 cm
630
)
(4065 cm
)
(4065 cm
2
2
720
)
(4646 cm
)
(4646 cm
2
2
900
2
)
(5807 cm
2
)
(5807 cm
1035
2
)
(6678 cm
2
)
(6678 cm
Installation & Operation Manual
The combustion air supply must be
completely free of any flammable vapors
that may ignite or chemical fumes which
may be corrosive to the appliance. Common
corrosive chemical fumes which must be
avoided are fluorocarbons and other
halogenated compounds, most commonly
present as refrigerants or solvents, such as
Freon, trichlorethylene, perchlorethylene,
chlorine, etc.
These chemicals, when
burned, form acids which quickly attack
the heat exchanger finned tubes, headers,
flue collectors, and the vent system. The
result is improper combustion and a non-
warrantable, premature unit failure.
Inside Air from
2 Ducts Delivered from Interior
Space
Bottom
Top
2
Opening, in
2
200
400
)
(2581 cm
)
2
2
250
500
2
)
(3226 cm
2
)
325
650
2
)
(4194 cm
2
)
375
750
2
)
(4839 cm
2
)
495
990
2
)
(6388 cm
2
)
630
1260
)
(8130 cm
)
2
2
720
1440
)
(9291 cm
)
2
2
900
1800
2
)
(11614 cm
2
)
1035
2070
2
)
(13356 cm
2
)
Bottom
Opening, in
2
400
(2581 cm
)
2
500
(3226 cm
2
)
650
(4194 cm
2
)
750
(4839 cm
2
)
990
(6388 cm
2
)
1260
(8130 cm
)
2
1440
(9291 cm
)
2
1800
(11614 cm
2
)
2070
(13356 cm
2
)
- Quick Links:
- Errors and Warnings
- Led Diagnostic Codes
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