58SP0A/58SP1A: Installation, Start–Up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
7
The requirements for combustion and ventilation air depend upon
whether or not the furnace is located in a space having a volume of at
least 50 cubic feet per 1,000 BTUh input rating for all gas appliances
installed in the space.
• Spaces having less than 50 cubic feet per 1,000 BTUh require the
OUTDOOR COMBUSTION AIR METHOD.
• Spaces having at least 50 cubic feet per 1,000 BTUh may use the
INDOOR COMBUSTION AIR, STANDARD or KNOWN AIR
INFILTRATION METHOD.
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.
illustrates how to provide TWO OUTDOOR OPENINGS,
one inlet and one outlet combustion and ventilation air opening, 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
c. TWO HORIZONTAL DUCTS require 1 sq. in. (645 sq. mm) of
free area per 2,000 BTUh (1,100 mm
2
/kW) of combined input
for all gas appliances in the space per
.
d. TWO OPENINGS OR VERTICAL DUCTS require 1 sq. in.
(645 sq. mm) of free area per 4,000 BTUh (550 mm
2
/kW) for
combined input of all gas appliances in the space per
and
.
3. ONE OUTDOOR OPENING requires:
a. 1 sq. in. (645 sq. mm) of free area per 3,000 BTUh (734
mm
2
/kW) for combined input of all gas appliances in the space
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.
–In
door Combustion Air
©
NFPA & AGA
–
Standard and Known-Air-Infiltration Rate
Methods
–I
ndoor air
is permitted for combustion, ventilation, and dilution, if the
Standard
or
Known-Air-Infiltration
Method is used.
* Minimum dimensions of 3-in. (76 mm).
NOTE
: Use any of the following combinations of openings:
A & B C & D D & E F & G
A03174
Fig. 6 – Air for Combustion, Ventilation,
and Dilution for Outdoors
Note: Not all models have these sizes.
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury or death.
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.
1 SQ IN.
PER
4000
BTUH*
DUCTS
TO
OUTDOORS
1 SQ IN.
PER 4000
BTUH*
CIRCULA
TING
AIR DUCTS
VENT
THROUGH
ROOF
D
B
A
C
E
1 SQ IN.
PER 4000
BTUH*
DUCT
TO
OUTDOORS
CIRCULATING AIR DUCTS
1 SQ IN.
PER 2000
BTUH*
1 SQ IN.
PER 2000
BTUH*
DUCTS
TO
OUTDOORS
12
″
MAX
12
″
MAX
12
″
MAX
12
″
MAX
12
″
MAX
OUTDOORS
1 SQ IN.
PER
4000
BTUH*
F
G
CLEARANCE IN FRONT
OF COMB
USTION AIR
OPENINGS SHALL BE
AT LEAST 3 IN.
(305mm)
(305mm)
(305mm)
(305mm)
(305mm)
(76mm)
Table 1 – Minimum Free Area Required for Each Combustion Air opening of Duct to Outdoors
FURNACE
INPUT
(BTUH)
TWO HORIZONTAL DUCTS
SINGLE DUCT OR OPENING
TWO OPENINGS OR VERTICAL DUCTS
(1 SQ. IN./2,000 BTUH) (1,100 SQ. MM/KW) (1 SQ. IN./3,000 BTUH) (734 SQ. MM/KW) (1 SQ. IN./4,000 BTUH) (550 SQ. MM/KW)
Free Area of Opening
and Duct
Sq. In. (Sq. mm)
Round Duct Dia.
In. (mm)
Free Area of Opening
and Duct
Sq. In. (Sq. mm)
Round Duct Dia.
In. (mm)
Free Area of Opening
and Duct
Sq. In. (Sq. mm)
Round Duct Dia.
In. (mm)
44,000
22 (14194)
6 (152)
14.7 (9484)
5 (127)
11 (7096)
4 (102)
66,000
33 (21290)
7 (178)
22 (14193)
6 (152)
16.5 (10645)
5 (127)
88,000
44 (28387)
8 (203)
29.3 (18903)
7 (178)
22 (14193)
6 (152)
110,000
55 (35484)
9 (229)
36.7 (23677)
7 (178)
27.5 (17742)
6 (152)
132,000
66 (42580)
10 (254)
44 (28387)
8 (203)
33 (21290)
7 (178)
154,000
77 (49677)
10 (254)
51.3 (33096)
9 (229)
38.5 (24839)
8 (203)
EXAMPLES: Determining Free Area
FURNACE
WATER HEATER
TOTAL INPUT
110,000
+
30,000
=
(140,000 divided by 4,000)
=
35.0 Sq. In. for each two Vertical Ducts or Openings
66,000
+
40,000
=
(106,000 divided by 3,000)
=
35.3 Sq. In. for a Single Duct or Opening
88,000
+
30,000
=
(118,000 divided by 2,000)
=
59.0 Sq. In. for each of two Horizontal Ducts