Filters; Duct System; Venting - Lennox EL180DFE Installation Instructions Manual

Filters

This unit is not equipped with a filter or rack. A field-pro­
vided high-velocity filter is required for the unit to operate
properly. Table 3 lists recommended filter sizes.
A filter must be in place any time the unit is operating.
IMPORTANT
If a high­efficiency filter is being installed as part of
this system to ensure better indoor air quality, the fil­
ter must be properly sized. High­efficiency filters
have a higher static pressure drop than standard­ef­
ficiency glass/foam filters. If the pressure drop is too
great, system capacity and performance may be re­
duced. The pressure drop may also cause the limit to
trip more frequently during the winter and the indoor
coil to freeze in the summer, resulting in an increase
in the number of service calls.
Before using any filter with this system, check the
specifications provided by the filter manufacturer
against the data given in the appropriate Lennox
Product Specifications bulletin. Additional informa­
tion is provided in Service and Application Note
ACC­00­2 (August 2000).
TABLE 3
Cabinet Width
A (14-1/2")
B (17-1/2")
C (21")

Duct System

Use industry‐approved standards (such as those pub­
lished by Air Conditioning Contractors of America or Ameri­
can Society of Heating, Refrigerating and Air Conditioning
Engineers) to size and install the supply and return air duct
system. This will result in a quiet and low‐static system that
has uniform air distribution.
NOTE - Do not operate the furnace in the heating mode
with an external static pressure that exceeds 0.5 inches
w.c. Higher external static pressures may cause erratic lim­
it operation.
Ensure that you have made a seal between the supply air
plenum and the furnace and between the furnace and the
return air plenum.
Return Air Filter Size (inches)
14 x 25 x 1 (1)
16 x 25 x 1 (1)
20 x 25 x 1 (1)
Return Air Plenum
Return air must not be drawn from a room where this
furnace, or any other gas-fueled appliance (i.e., water
heater), or carbon monoxide-producing device (i.e.,
wood fireplace) is installed. When return air is drawn
from a room, a negative pressure is created in the room. If
a gas appliance is operating in a room with negative pres­
sure, the flue products can be pulled back down the vent
pipe and into the room. This reverse flow of the flue gas
may result in incomplete combustion and the formation
of carbon monoxide gas. This toxic gas might then be dis­
tributed throughout the house by the furnace duct sys­
tem.

Venting

A 4-inch diameter flue transition is factory‐installed on all
models. Modifying or removing the flue transition will
cause the unit to operate unsafely and will void the unit
certification. The vent connector does not require insula­
tion.
The EL180DFE series units are classified as fan-assisted
Category I furnaces when vertically vented according to
the latest edition of National Fuel Gas Code (NFPA 54 /
ANSI Z223.1). A fan-assisted Category I furnace is an ap­
pliance equipped with an integral mechanical means to ei­
ther draw or force combustion products through the com­
bustion chamber and/or heat exchanger.
NOTE - Use these instructions as a guide. They do not su­
persede local codes. This furnace must be vented accord­
ing to all local codes, these installation instructions, and the
provided venting tables in these instructions
The venting tables in this manual were extracted from the
National Fuel Gas Code (NFPA 54 / ANSI Z223.1) and are
provided as a guide for proper vent installation. Proper ap­
plication, termination, construction and location of vents
must conform to local codes having jurisdiction. In the ab­
sence of local codes, the NFGC serves as the defining doc­
ument.
Refer to the tables and the venting information contained in
these instructions to properly size and install the venting
system.
IMPORTANT
Once the venting system is installed, attach the "Dis­
connected Vent" warning sticker to a visible area of
the plenum near the vent pipe. The warning sticker
is provided in the bag assembly. Order kit 66W04 for
additional stickers.
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