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1. The heater must be provided with adequate sup-
ply of air for proper combustion and ventilation in
accordance with the latest edition of the National
Fuel Gas Code, ANSI Z223.1, or applicable provi-
sions of the local building codes.
2. When the heater is installed in a confined space
where all air is supplied from inside the building,
the heater room must be provided with TWO
openings, each one having a minimum net free
area, in square inches as shown in Table D.
One opening shall be within 12 inches of the top,
and the other opening within 12 inches of the floor.
If additional gas appliances are installed in the
same space, the total input of all gas appliances
installed in the same space, must be considered in
the calculation. Refer to Sec. 5.3.5 of the latest
edition of the National Fuel Gas Code for addition-
al requirements.
3. If the heater room is located against an outside
wall and air openings can communicate directly
with the outdoors, the TWO openings on the out
side wall must each have a net free area, in
square inches as shown in Table E.
Location of the openings is the same as in the pre-
vious case - that is, within 12 inches of the top,
and within 12 inches of the bottom of the enclo-
Model No. Sq. in. of Each Free Area
0260/0261 264
0330/0331 334
0400/0401 399
Table D: Minimum Net Free Area
sure. If horizontal ducts are used, the area must
be doubled and the duct area shall not be less
than the area of the openings they connect, and in
no case shall the smallest dimension be less than
3 inches.
Outdoor Models
Heaters must not be installed under an overhang of
less than three (3) feet from the top on the heater.
Three (3) sides must be open in the area under the
overhang. Roof water drainage must be diverted away
from the heater installed under overhangs with the use
of gutters.
The point from where the flue products exit the heater
must be a minimum of four (4) feet below, four (4) feet
horizontally from or one (1) foot above any door, win-
dow or gravity inlet to a building. The top surface of the
heater shall be at least three (3) feet above any forced
air inlet, or intake ducts located within ten (10) feet hor-
izontally.
In areas where high winds are frequent, it may be nec-
essary to locate the heater a minimum of three (3) feet
from high vertical walls, or install a wind break so the
heater is not in direct wind current.
Venting Connections
Outdoor Models
Outdoor vent top is shipped separately and must be
installed on site.
Models 0260–0401
1. Insert screw retainer clip over mounting flange, (4
places).
Model No. Sq. in. of Each Free Area
0260/0261 66
0330/0331 84
0400/0401 100
Table E: Minimum Net Free Area
NOTE: If louvers, grills or screens are used on the
openings, obtain the net free area from their supplier
or manufacturer. If the design free area of a louver is
not known nor available, it shall be assumed that
wood louvers will have 20-25 percent free area and
metal louvers will have 60-75 percent free area as
shown in the National Fuel Gas Code.
Fig. 3: Location of Mounting Clips