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Installed in Combination with a Cooling Coil
When this furnace is used with cooling units, it shall be
installed in parallel with, or on the upstream side of, cool-
ing units to avoid condensation in the heating compart-
ment. See FIGURE 1. With a parallel ow arrangement,
a damper (or other means to control the ow of air) must
adequately prevent chilled air from entering the furnace. If
the damper is manually operated, it must be equipped to
prevent operation of either the heating or the cooling unit,
unless it is in the full HEAT or COOL setting. See FIGURE
1.
Gas Unit
Heating Unit Installed Upstream of Cooling Unit
Gas Unit
Dampers
(open during heating operation only)
Dampers
(open during cooling operation only)
Heating Unit Installed Parallell to Air Handler Unit
Air Handler Unit
Evaporator
FIGURE 1
When installed, this furnace must be electrically grounded
according to local codes. In addition, in the United States,
installation must conform with the current National Elec-
tric Code, ANSI/NFPA No. 70. The National Electric Code
(ANSI/NFPA No. 70) is available from the following ad-
dress:
National Fire Protection Association
1 Battery March Park
Quincy, MA 02269
NOTE - This furnace is designed for a minimum continu-
ous return air temperature of 60°F (16°C) or an intermittent
operation down to 55°F (13°C) dry bulb for cases where a
night setback thermostat is used. Return air temperature
must not exceed 85°F (29°C) dry bulb.
The EL180UHNE furnace may be installed in alcoves,
closets, attics, basements, garages, crawl spaces and
utility rooms in the upow or horizontal position.
This furnace design has not been CSA International
certied for installation in mobile homes, recreational
vehicles, or outdoors.
Use of Furnace as Construction Heater
Lennox does not recommend the use of EL180UHNE
units as a construction heater during any phase of con-
struction. Very low return air temperatures, harmful vapors
and operation of the unit with clogged or misplaced lters
will damage the unit.
EL180UHNE units may be used for heating of buildings or
structures under construction, if the following conditions
are met:
• The vent system must be permanently installed per
these installation instructions.
• A room thermostat must control the furnace. The
use of xed jumpers that will provide continuous
heating is not allowed.
• The return air duct must be provided and sealed to
the furnace.
• Return air temperature range between 60°F (16°C)
and 80°F (27°C) must be maintained.
• Air lters must be installed in the system and must
be maintained during construction.
• Air lters must be replaced upon construction com-
pletion.
• The input rate and temperature rise must be set per
the furnace rating plate.
• One hundred percent (100%) outdoor air must be
provided for combustion air requirements during
construction. Temporary ducting may supply out-
door air to the furnace. Do not connect duct directly
to the furnace. Size the temporary duct following
these instructions in section for Combustion, Dilu-
tion and Ventilation Air in a conned space with air
from outside.
• The furnace heat exchanger, components, duct
system, air lters and evaporator coils must be
thoroughly cleaned following nal construction
clean-up. All furnace operating conditions (includ-
ing ignition, input rate, temperature rise and vent-
ing) must be veried according to these installation
instructions.