Unit Support - Lennox LGM092U Installation Instructions Manual

Use of this unit as a construction heater or air conditioner
is not recommended during any phase of construction.
Very low return air temperatures, harmful vapors and
operation of the unit with clogged or misplaced filters will
damage the unit.
If this unit has been used for heating or cooling of
buildings or structures under construction, the following
conditions must be met or the warranty will be void:
S A room thermostat or zone air temperature sensor
must control the unit. The use of fixed jumpers that
will provide continuous heating or cooling is not
allowed.
S A pre-filter must be installed at the entry to the return
air duct.
S The return air duct must be provided and sealed to
the unit.
S Return air temperature range between 55°F (13°C)
and 80°F (27°C) must be maintained.
S Air filters must be replaced and pre-filters must be
removed upon construction completion.
S The input rate and temperature rise must be set per
the unit rating plate.
S The heat exchanger, components, duct system, air
filters and evaporator coil must be thoroughly
cleaned following final construction clean-up.
S The unit operating conditions (including airflow,
cooling operation, ignition, input rate, temperature
rise and venting) must be verified according to these
installation instructions.

Unit Support

In downflow discharge installations, install the unit on a
non-combustible surface only. Unit may be installed on
combustible surfaces when used in horizontal discharge
applications or in downflow discharge applications when
installed on an C1CURB7*B roof mounting frame.
NOTE - Securely fasten roof frame to roof per local codes.
CAUTION
To reduce the likelihood of supply / return air by­
pass and promote a proper seal with the RTU, duct
work / duct drops / diffuser assemblies must be
supported independently to the building structure.
A-Downflow Discharge Application
Roof Mounting with C1CURB7*B
1- The C1CURB7*B roof mounting frame must be
installed, flashed and sealed in accordance with the
instructions provided with the frame.
2- The C1CURB7*B roof mounting frame should be
square and level to 1/16" per linear foot (5mm per
linear meter) in any direction.
3- Duct must be attached to the roof mounting frame
and not to the unit; supply and return plenums must
be installed before setting the unit.
Installer's Roof Mounting Frame
Many types of roof frames can be used to install the unit
depending upon different roof structures. Items to keep
in mind when using the building frame or supports are:
1- The base is fully enclosed and insulated, so an
enclosed frame is not required.
2- The frames or supports must be constructed with
non-combustible materials and should be square and
level to 1/16" per linear foot (5mm per linear meter)
in any direction.
3- Frame or supports must be high enough to prevent
any form
Recommended minimum frame height is 14"
(356mm).
4- Duct must be attached to the roof mounting frame
and not to the unit. Supply and return plenums must
be installed before setting the unit.
5- Units require support along all four sides of unit base.
Supports must be constructed of steel or suitably
treated wood materials.
NOTE-When installing a unit on a combustible surface for
downflow discharge applications, an C1CURB7*B roof
mounting frame is required.
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of moisture from entering unit.