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935SB: Installation, Start-up, Operating and Service Maintenance Instructions
CAUTION
!
FURNACE CORROSION HAZARD
Failure to follow this caution may result in furnace damage.
Air for combustion must not be contaminated by halogen compounds,
which include fluoride, chloride, bromide, and iodide. These elements
can corrode heat exchangers and shorten furnace life. Air contaminants
are found in aerosol sprays, detergents, bleaches, cleaning solvents,
salts, air fresheners, and other household products.
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury or death.
The operation of exhaust fans, kitchen ventilation fans, clothes dryers,
attic exhaust fans or fireplaces could create a NEGATIVE PRESSURE
CONDITION at the furnace. Make-up air MUST be provided for the
ventilation devices, in addition to that required by the furnace. Refer to
the Carbon Monoxide Poisoning Hazard warning in the venting section
of these instructions to determine if an adequate amount of make-up air
is available.
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 (4.8 cubic
meters per kW) require the Outdoor Combustion Air Method.
• Spaces having at least 50 cubic feet per 1,000 BTUh (4.8 cubic meters
per kW) 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. Provide TWO OUTDOOR OPENINGS, one inlet and one outlet
combustion and ventilation air opening, to the outdoors (see
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 (see
c. TWO HORIZONTAL DUCTS require 1 sq. in. (645 sq. mm) of
free area per 2,000 BTUh (1,100 mm2/kW) of combined input
for all gas appliances in the space (see
d. TWO OPENINGS OR VERTICAL DUCTS require 1 sq. in.
(645 sq. mm) of free area per 4,000 BTUh (550 mm2/kW) for
combined input of all gas appliances in the space (see
Table
4).
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 appliances in the space
(see
Fig. 8
and
Table
4).
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.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Fig.
Fig. 8
and
Table
4).
Fig. 8
and
Table
4).
Fig. 8
Indoor Combustion Air© 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.
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
(Table
required volume for each appliance in the space and add the volumes
together to get the total minimum required volume for the space.
Table 5
- 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:
Volume
2. For fan-assisted appliances such as this furnace:
8).
Volume
I
If:
other = combined input of all other than fan-assisted appliances in
BTUh/hr
I
fan = 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
and
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.2/1,000 BTUh (2,000 mm2/kW) of the
total input rating of all gas appliances in the space, but not less
than 100 in.2 (0.06 m2). 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
Fig.
9)
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
9
WARNING
!
5) or Equations 1 and 2. Determine the minimum
I
= 21ft
3
other
ACH
1000 Btu/hr
Other
I
= 15ft
3
fan
ACH
1000 Btu/hr
Fan
A04002
A04003
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