International comfort products F8MVL Installation Instructions Manual page 9

c. TWO HORIZONTAL DUCTS require 1 sq. in. (645
sq. mm) of free area per 2,000 Btuh (1,100 mm
of combined input for all gas appliances in the space
per Figure 7 and Table 2.
d. TWO OPENINGS OR VERTICAL DUCTS require 1
sq. in. (645 sq. mm) of free area per 4,000 Btuh (550
2
mm /kW) for combined input of all gas appliances in
the space per Figure 7 and Table 2.
3. ONE OUTDOOR OPENING requires:
a. 1 sq. in. (645 sq. mm) of free area per 3,000 Btuh
(734 mm2/kW) for combined input of all gas appli-
ances in the space per Table 2 and
b. Not less than the sum of the areas of all vent con-
nectors in the space.
Figure 8 − Air for Combustion, Ventilation, and Dilution
from Indoors
CIRCULATING AIR
DUCTS
INTERIOR
HEATED
SPACE
CIRCULATING AIR DUCTS
* Minimum opening size is 100 sq in. (64516 sq. mm)with minimum dimensions of 3
in. (76 mm)
† Minimum of 3 in. (76 mm) when type‐B1 vent is used.
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.
Indoor Combustion AirE NFPA & AGA
Standard and Known−Air−Infiltration Rate Methods
Indoor air is permitted for combustion, ventilation, and
dilution, if the Standard or Known−Air−Infiltration Method is
used.
441 01 2122 01
2
/kW)
VENT THROUGH ROOF
12" MAX (305mm)
1 SQ IN.
PER 1000
BTUH* IN DOOR
OR WALL
UNCONFINED
SPACE
6" MIN (152mm)
(FRONT)
Ü
1 SQ IN.
PER 1000
BTUH* IN DOOR
OR WALL
12" MA X (305mm)
A03175
Specifications are subject to change without notice.
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.
The Standard Method:
1. The space has no less volume than 50 cubic feet per
1,000 Btuh of the maximum input ratings for all gas appli-
ances installed in the space and
2. The air infiltration rate is not known to be less than 0.40 air
changes per hour (ACH).
The Known Air Infiltration Rate Method shall be used, if the
infiltration rate is known to be:
1. Less than 0.40 ACH and
2. Equal to or greater than 0.10 ACH
Infiltration rates greater than 0.60 ACH shall not be used. The
minimum required volume of the space varies with the number
of ACH and shall be determined per Table 3 or Equations 1
and 2. Determine the minimum required volume for each
appliance in the space and add the volumes together to get
the total minimum required volume for the space.
Table 3 − Minimum Space Volumes were determined by
using the following equations from the National Fuel Gas Code
ANSI Z223.1−2012/NFPA 54−2012, 9.3.2.2:
1. For other than fan−assisted appliances, such as a draft
hood−equipped water heater:
= 21ft
3
Volume
ACH
Other
2. For fan−assisted appliances such as this furnace:
= 15ft
3
Volume
ACH
Fan
If: Iother = combined input of all other than fan−assisted
appliances in Btuh/hr
Ifan = combined input of all fan−assisted appliances in Btuh/hr
ACH = air changes per hour (ACH shall not exceed 0.60.)
The following requirements apply to the Standard Method and
to the Known Air Infiltration Rate Method.
1. Adjoining rooms can be considered part of a space if:
a. There are no closeable doors between rooms.
b. Combining spaces on same floor level. Each open-
ing shall have free area of at least 1 in.
2
(2,000 mm /kW) of the total input rating of all gas
appliances in the space, but not less than 100 in.
2
(0.06 m ). One opening shall commence within 12
in. (300 mm) of the ceiling and the second opening
shall commence within 12 in. (300 mm) of the floor.
The minimum dimension of air openings shall be at
least 3 in. (80 mm). (See Figure 8)
I
other
1000 Btu/hr
I
fan
1000 Btu/hr
2
/1,000 Btuh
A04002
A04003
2
9