General; Combustion, Dilution & Ventilation Air - Lennox ML193UH Installation Instructions Manual

• Air filters 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 confined space with air
from outside.
• The furnace heat exchanger, components, duct
system, air filters and evaporator coils must be
thoroughly cleaned following final construction
clean-up. All furnace operating conditions (includ-
ing ignition, input rate, temperature rise and vent-
ing) must be verified according to these installation
instructions.

General

These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
In addition to the requirements outlined previously, the
following general recommendations must be considered
when installing a ML193UH furnace:
• Place the furnace as close to the center of the air
distribution system as possible. The furnace should
also be located close to the vent termination point.
• When the furnace is installed in non-direct vent ap-
plications, do not install the furnace where drafts
might blow directly into it. This could cause improp-
er combustion and unsafe operation.
• When the furnace is installed in non-direct vent ap-
plications, do not block the furnace combustion air
opening with clothing, boxes, doors, etc. Air is need-
ed for proper combustion and safe unit operation.
• When the furnace is installed in an attic or other
insulated space, keep insulation away from the fur-
nace.
• When the furnace is installed in an unconditioned
space, consider provisions required to prevent
freezing of condensate drain system.
• Please consult the manufacturer of your evaporator
coil for their recommendations on distance required
between the heat exchanger and their drain pan.
Adequate space must be provided between the
drain pan and the furnace heat exchanger.
ML193UH unit should not be installed in areas normally
subject to freezing temperatures.
This prodcut contains a chemical known to the State
of California to cause cancer, birth defects, or other
reproductive harm.
Insufficient combustion air can cause headaches,
nausea, dizziness or asphyxiation. It will also cause
excess water in the heat exchanger resulting in rusting
and premature heat exchanger failure. Excessive
exposure to contaminated combustion air will result
in safety and performance related problems. Avoid
exposure to the following substances in the combustion
air supply:
Permanent wave solutions
Chlorinated waxes and cleaners
Chlorine base swimming pool chemicals
Water softening chemicals
De-icing salts or chemicals
Carbon tetrachloride
Halogen type refrigerants
Cleaning solvents (such as perchloroethylene)
Printing inks, paint removers, varnishes, etc.
Hydrochloric acid
Cements and glues
Antistatic fabric softeners for clothes dryers
Masonry acid washing materials
Combustion, Dilution & Ventilation Air
If the ML193UH is installed as a Non-Direct Vent Fur-
nace, follow the guidelines in this section.
NOTE - In Non-Direct Vent installations, combustion air is
taken from indoors or ventilated attic or crawlspace and
flue gases are discharged out-doors.
In the past, there was no problem in bringing in sufficient
outdoor air for combustion. Infiltration provided all the air
that was needed. In today's homes, tight construction
practices make it necessary to bring in air from outside
for combustion. Take into account that exhaust fans, ap-
pliance vents, chimneys, and fireplaces force additional
air that could be used for combustion out of the house.
Unless outside air is brought into the house for combus-
tion, negative pressure (outside pressure is greater than
Combustion, Dilution & Ventilation Air
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CAUTION
WARNING
WARNING