Unit Support; Duct Connection - Lennox LCH Series 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 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 T1CURB / C1CURB / E1CURB 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 T1CURB / C1CURB / E1CURB
1- The roof mounting frame must be installed, flashed
and sealed in accordance with the instructions
provided with the frame.
2- The 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 of
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, a T1CURB / C1CURB /
E1CURB roof mounting frame is required.
B-Horizontal Discharge Applications
1- Units which are equipped with an optional
economizer and installed in horizontal airflow
applications must use a horizontal conversion kit.
2- Specified installation clearances must be maintained
when installing units. Refer to figure 1.
3- Top of support slab should be approximately 4"
(102mm) above the finished grade and located so no
run-off water from higher ground can collect around
the unit.
4- Units require support along all four sides of unit base.
Supports must be constructed of steel or suitably
treated wood materials.

Duct Connection

All exterior ducts, joints and openings in roof or building
walls must be insulated and weather-proofed with
flashing and sealing compounds in accordance with
applicable codes. Any duct passing through an
unconditioned space must be insulated.
CAUTION
In downflow applications, do not drill or punch
holes in base of unit. Leaking in roof may occur if
unit base is punctured.
Page 6
moisture from entering
LGH/LCH036, 048, 060, 072, 074
unit.