5.3.4 Specially Engineered Installations:
The requirements of 5.3.3 shall not necessarily govern when special
engineering, approved by the authority having jurisdiction, provides an
adequate supply of air for combustion, ventilation, and dilution of flue
gases.
5.3.5 Louvers and Grilles:
In calculating free area in 5.3.3, consideration shall be given to the block-
ing effect of louvers, grilles or screens protecting openings. Screens used
shall not be smaller than 1/4 inch mesh. If the area through a design of
louver or grille is known, it should be used in calculating the size of
opening required to provide the free area specified. If the design and free
area is not known, it may be assumed that wood louvers will have 20-25
percent free area and metal louvers and grilles will have 60-75 percent
free area. Louvers and grilles shall be fixed in the open position or
interlocked with the equipment so that they are opened automatically
during equipment operation.
5.3.6 Special Conditions Created by Mechanical Exhausting or Fire-
places:
Operation of exhaust fans, ventilation systems, clothes dryers, or fire-
places may create conditions requiring special attention to avoid unsat-
isfactory operation of installed gas utilization equipment. Air from
Inside Building. See 5.3.3-a.
VI. INSTALLATION POSITIONS
NOTE: This furnace is shipped from the factory as a Dedicated
Upflow. A “Blocked Drain Kit” (0270K00012) is available and MUST
BE USED if the furnace is installed Horizontal Left or Horizontal
Right.
This furnace may be installed in an upright position or horizontal
on either the left or right side panel. Do not install this furnace on
its back. For upright upflow furnaces, return air ductwork may be
attached to the side panel(s) and/or basepan. For horizontal upflow
furnaces, return air ductwork must be attached to the basepan.
NOTE: Ductwork must never be attached to the back of the furnace.
Contact your distributor for proper airflow requirements and num-
ber of required ductwork connections. Refer to “Recommended
Installation Positions” figure for appropriate installation positions,
ductwork connections, and resulting airflow arrangements.
VII. HORIZONTAL APPLICATIONS & CONSIDERATIONS
NOTE: This furnace is shipped from the factory as a Dedicated
Upflow. A “Blocked Drain Kit” is available and MUST BE USED if the
furnace is installed Horizontal Left or Horizontal Right. Check the
Serial/ Rating Plate on the furnace for the Kit P/N.
G
ENERAL
Horizontal applications, in particular, may dictate many of the
installation’s specifics such as airflow direction, ductwork connec-
tions, flue and combustion air pipe connections, etc. The basic
application of this furnace as a horizontal furnace differs only slightly
from an upright installation. When installing a furnace horizontally,
additional consideration must be given to the following: