Table 3-Minimum Space Volumes were determined by using the following equations from the National Fuel Gas Code ANSI Z223.1-2002/NFPA
54-2002,8.3.2.2:
1. For other than fan-assisted appliances, such as a draft hood-equipped water heater:
2. For fan-assisted appliances such as this furnace:
If:
I
other
= combined input of all other than fan-assisted appliances in Btu/hr
I
fan
= combined input of all fan-assisted appliances in Btu/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 closable doors between rooms.
b. Combining spaces on same floor level. Each opening shall have free area of at least 1 in.
2
/1,000 Btuh (2,000 mm
2
/kW) of the total input
rating of all gas appliances in the space, but not less than 100 in.
2
(0.06 m
2
). One opening shall commence within 12
″
(300 mm) of the
ceiling and the second opening shall commence within 12
″
(300 mm) of the floor. The minimum dimension of air openings shall be at
least 3 in. (80 mm). (See Fig. 19.)
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
/1,000 Btuh (4,400 mm
2
/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.
2
/4,000 Btuh of 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.
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.
NOTE:
In determining the free area of an opening, the blocking effect of the louvers, grilles, and screens must be considered. If the free area of
a louver or grille design is unknown, it may be assumed that wood louvers have a 20 percent free area, and metal louvers or grilles have a 60 percent
free area. Screens, when used, must not be smaller than 1/4-in. mesh. Louvers and grilles must be constructed so they cannot be closed.
When combustion air ducts are used, they must be of the same cross sectional area as the free area of the openings to which they connect. The
minimum dimension of ducts must not be less than 3 in. (80mm).
INSTALLATION
PROCEDURE 1—LEVELING LEGS (IF DESIRED)
When furnace is used in upflow position with side inlet(s), leveling legs may be desired. (See Fig. 20.) Install field-supplied, corrosion-resistant
5/16-in. machine bolts and nuts.
NOTE:
The maximum length of bolt should not exceed 1-1/2 in.
1. Position furnace on its back. Locate and drill a 5/16-in. diameter hole in each bottom corner of furnace. (See Fig. 20.) Holes in bottom
closure panel may be used as guide locations.
2. For each hole, install nut on bolt and then install bolt and nut in hole. (Install flat washer if desired.)
3. Install another nut on other side of furnace base. (Install flat washer if desired.)
4. Adjust outside nut to provide desired height, and tighten inside nut to secure arrangement.
NOTE:
Bottom closure must be used when leveling legs are used. See Bottom Closure Panel section.
PROCEDURE 2—INSTALLATION IN UPFLOW OR DOWNFLOW APPLICATIONS
NOTE:
For downflow applications, this furnace is approved for use on combustible flooring when manufacturer’s accessory floor base Part No.
KGASB0201ALL is used. Manufacturer’s accessory floor base in not required when this furnace is installed on manufacturer’s Coil Assembly Part
No. CD5, CK5, or Coil Box Part No. KCAKC is used.
A04002
Volume
Other
= 21ft
3
ACH
I
other
1000 Btu/hr
A04003
Volume
Fan
= 15ft
3
ACH
I
fan
1000 Btu/hr
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