Maytag Amana GM9S92 Manual page 10

SYSTEM OPERATION
(2)*Where communicating with the outdoors through horizon-
tal ducts, each opening shall have a minimum free area
of 1 in. /2000 Btu/hr (1100 min
2
all appliances in the enclosure. [See Figure A.9.3.3.1(2).]
Chimney or Gas Vent
Water
Heater
Furnace
Figure A.9.3.3.1(2) All Combustion Air From Outdoors
through Horizontal Ducts.
9.3.3.2* One Permanent Opening Method. One perma-
nent openings, commencing within 12 in. (300 mm) of the
top of the enclosure, shall be provided. The appliance shall
have clearances of at least 1 in. (25 mm) from the sides and
back and 6 in. (150 mm) from the front of the appliance.
The opening shall directly communicate with the outdoors
or shall communicate through a vertical or horizontal duct
to the outdoors or spaces that freely communicate with the
outdoors (see Figure A.9.3.3.2) and shall have a minimum
free area of the following:
(1) 1 in. /3000 Btu/hr (700 mm
2
rating of all appliances located in the enclosure, and
(2) Not less than the sum of the areas of all vent connectors
in the space.
NOTE: The single opening must have
a free area of not less than one
square inch per 3000 BTU of
the total input rating of all equip-
ment in the enclosure, but not less than
the sum of the areas of all vent
connectors in the confined space.
Figure A.9.3.3.2 All Combustion Air
From Outdoors through Single Combustion Air Opening.
9.3.4 Combination Indoor and Outdoor Combustion Air.
The use of a combination of indoor and outdoor combustion
air shall be in accordance with (1) through (3) [see example
calculation in Annex J]:
(1) Indoor Openings: Where used, openings connecting the
interior spaces shall comply with 9.3.2.3.
(2) Outdoor Opening(s) Location. Outdoor opening(s) shall
be located in accordance with 9.3.3.
10
/kW) of total input rating of
2
NOTE: The air duct openings
must have a free area of not
less than one square inch per
2000 BTU of the total input
rating of all equipment in the
enclosure*.
Outlet air duct
Inlet air duct
per kW) of the total input
2
Chimney or Gas Vent
Water
Heater
Furnace
(3) Outdoor Opening(s) Size. The outdoor opening(s) size
shall be calculated in accordance with the following:
(a) The ratio of the interior spaces shall be the available
volume of all communicating spaces divided by the
required volume.
(b) The outdoor size reduction factor shall be 1 minus
the ratio of interior spaces.
(c) The minimum size of outdoor opening(s) shall be the
full size of outdoor opening(s) calculated in accor-
dance with 9.3.3, multiplied by the reduction factor.
The minimum dimension of air openings shall not be
less than 3 in. (80 mm).
9.3.5 Engineered Installations. Engineered combustion air
installations shall provide an adequate supply of combustion,
ventilation, and dilution air and shall be approved by the au-
thority having jurisdiction.
9.3.6 Mechanical Combustion Air Supply. Where all com-
bustion air is provided by a mechanical air supply system,
the combustion air shall be supplied form outdoors at the
minimum rate of 0.35 ft
per kW) for all appliances located within the space.
9.3.6.1 Where exhaust fans are installed, additional air shall
be provided to replace the exhausted air.
9.3.6.2 Each of the appliances served shall be interlocked
to the mechanical air supply system to prevent main burner
operation where the mechanical air supply system is not in
operation.
9.3.6.3 Where combustion air is provided by the building's
mechanical ventilation system, the system shall provide
the specified combustion air rate in addition to the required
ventilation air.
9.3.7 Louvers, Grilles, and Screens.
9.3.7.1 Louvers and Grilles. The required size of openings
for combustion, ventilation, and dilution air shall be based
on the net free area of each opening. Where the free area
through a design of louver or grille or screen is known, it shall
be used in calculating the size opening required to provide
the free area specified. Where the louver and grille design
Opening
and free area are not known, it shall be assumed that wood
louvers will have 25 percent free area, and metal louvers and
Alternate
Opening
grilles will have 75 percent free area. Nonmotorized louvers
Location
and grilles shall be fixed in the open position.
9.3.7.2 Minimum Scree Mesh Size. Screens shall not be
smaller than 1/4 in. mesh.
9.3.7.3 Motorized Louvers. Motorized louvers shall be inter-
locked with the appliance so they are proven in the full open
position prior to main burner ignition and during main burner
operation. Means shall be provided to prevent the main burn-
er form igniting should the louver fail to open during burner
startup and to shut down the main burner if the louvers close
during burner operation.
9.3.8 Combustion Air Ducts. Combustion air ducts shall
comply with 9.3.8.1 through 9.3.8.8.
/min per 1000 Btu/hr (0.034 m
3
/min
3