Lennox LGH036, LGH048, LGH060, LGH072, LGH074 Installation Instructions Manual

See unit nameplate for manufacturer
and address.
©2021
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
PACKAGED GAS UNITS
506373-03
8/2021
Supersedes 7/2020

Table of Contents

Safety . . . . . . . . . . . . . . . . . . . . . . . . . 1
Connect Gas Piping . . . . . . . . . . . . . . . . . . 3
High Alititue Derate. . . . . . . . . . . . . . . . . . . 4
Pressure Test Gas Piping . . . . . . . . . . . . . . . 4
Two Stage Gas Valve Adjustment . . . . . . . . . . . 5
Gas Heat Operation . . . . . . . . . . . . . . . . . . 5
Typical Gas Heat Schematic . . . . . . . . . . . . . . 6
Typical Unit Schematic . . . . . . . . . . . . . . . . . 7
Proper Gas Flow . . . . . . . . . . . . . . . . . . . . 8
Repair Parts Listing . . . . . . . . . . . . . . . . . . 8

Safety

WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, personal
injury or loss of life. Installation and service must be
performed by a licensed professional HVAC installer or
equivalent, service agency, or the gas supplier.
Use of this unit as a construction heater or air condition-
er is not recommended during any phase of construction.
Very low return air temperatures, harmful vapors and op-
eration of the unit with clogged or misplaced filters will
damage the unit.
If this unit has been used for heating or cooling of build-
ings or structures under construction, the following condi-
tions must be met or the warranty will be void:
• The vent hood must be installed per these installation
instructions.
• A room thermostat must control the unit. The use of
fixed jumpers that will provide continuous heating or
cooling is not allowed
• A pre-filter must be installed at the entry to the return
air duct.
• The return air duct must be provided and sealed to the
unit.
INSTALLATION
INSTRUCTIONS
AGENCY REQUIRED
LGH036-360 UNITS
3 THROUGH 30 TONS
• Return air temperature range between 55°F (13°C) and
• Air filters must be replaced and pre-filter must be removed
• The input rate and temperature rise must be set per the
• The heat exchanger, components, duct system, air filters
• The unit operating conditions (including airflow, cooling op-
NOTE - The Commonwealth of Massachusetts stipulates
these additional requirements:
• Gas units shall be installed by a licensed plumber or
• The gas cock must be "T handle" type.
The unit is certified for installation on noncombustible floors
only. However, it may be installed on wood flooring, or on
class A, class B, or class C material covered floors when
used in horizontal discharge applications or in downflow
discharge applications when mounted on an LARMF roof
mounting frame.
Adequate clearance shall be provided around air openings
into the vestibule area. Provisions shall be made for proper
operation and for combustion air and ventilation air supply.
Unit must be adjusted for the temperature rise range and
within the allowable external static pressure on furnaces with
a duct system as listed on unit nameplate.
80°F (27°C) must be maintained.
upon construction completion.
unit r ating plate.
and evaporator coil must be thoroughly cleaned following
final construction clean-up.
eration, ignition, input rate, temperature rise and venting)
must be verified according to these installation instructions.
gas fitter only.