International comfort products R9MSB0801716 Installation Instructions Manual page 10

INSTALLATION INSTRUCTIONS
of combined input for all gas appliances in the space
per Figure 6 and Table 3.
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 6 and Table 3.
3. ONE OUTDOOR OPENING requires:
a. 1 sq. in. (645 sq. mm) of free area per 3,000 Btuh
2
(734 mm /kW) for combined input of all gas
appliances in the space per Figure 6 and Table 3.
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.
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.
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.
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
appliances 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 4 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 4 − Minimum Space Volumes were determined by using
the following equations from the current edition of the National
Fuel Gas Code ANSI Z223.1/NFPA 54, 9.3.2.2:
1. For other than fan−assisted appliances, such as a draft
hood−equipped water heater:
= 21ft
3
Volume
ACH 1000 Btu/hr
Other
10
I
other
A04002
Specifications subject to change without notice.
2. For fan−assisted appliances such as this furnace:
= 15ft
3
Volume
ACH 1000 Btu/hr
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 opening
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 7.)
c. Combining space on different floor levels. The
volumes of spaces on different floor levels shall be
considered as communicating spaces if connected by
one or more permanent openings in doors or floors
having free area of at least 2 in.
2
mm /kW) of total input rating of all gas appliances.
2. An attic or crawlspace may be considered a space that
freely communicates with the outdoors provided there
are adequate permanent ventilation openings directly to
outdoors having free area of at least 1−in.
total input rating for all gas appliances in the space.
3. In spaces that use the Indoor Combustion Air Method,
infiltration should be adequate to provide air for
combustion, permanent ventilation and dilution of flue
gases. However, in buildings with unusually tight
construction, additional air MUST be provided using the
methods described in the Outdoor Combustion Air
Method section.
4. Unusually tight construction is defined as Construction
with:
a. Walls and ceilings exposed to the outdoors have a
continuous, sealed vapor barrier. Openings are
gasketed or sealed and
b. Doors and openable windows are weatherstripped
and
c. Other openings are caulked or sealed. These include
joints around window and door frames, between sole
plates and floors, between wall−ceiling joints,
between wall panels, at penetrations for plumbing,
electrical and gas lines, etc.
Combination of Indoor and Outdoor Air
1. Indoor openings shall
Combustion Air Method below and,
2. Outdoor openings shall be located as required in the
Outdoor Combustion Air Method mentioned previously
and,
3. Outdoor openings shall be sized as follows:
a. Calculate the Ratio of all Indoor Space volume
divided by required volume for Indoor Combustion
Air Method below.
b. Outdoor opening size reduction Factor is 1 minus the
Ratio in a. above.
c. Minimum size of Outdoor openings shall be the size
required in Outdoor Combustion Air Method above
multiplied by reduction Factor in b. above. The
minimum dimension of air openings shall be not less
than 3 in. (80 mm).
Gas Furnace: R9MSB
I
fan
A04003
2
/1,000 Btuh
2
2
/1,000 Btuh (4,400
2
/4,000 Btuh of
comply with the Indoor
440 01 6001 05