Lennox LGM Series Unit Information

S e r v i c e L i t e r a t u r e
LGM036U, 048U, 060U, and 074U are ultra high efficien-
cy gas packaged units equipped with variable speed di-
rect drive blowers, an inverter-driven variable speed com-
pressor, and a variable speed outdoor fan.
LGM036 units are available in 65,000 to 108,000 Btuh
(19 to 31 kW) heating inputs. LGM048, 060 and 074 units
are available in 65,000 to 150,000 Btuh (19 to 43.9 kW)
heating inputs. Gas heat sections are designed with alu-
minized (stainless optional) steel tube heat exchangers.
Cooling capacities range from 3 to 6 tons (7 to 21kW).
Information contained in this manual is intended for use
by qualified service technicians only. All specifications are
subject to change. Procedures outlined in this manual are
presented as a recommendation only and do not super-
sede or replace local or state codes.
If the unit must be lifted for service, rig unit by attaching
four cables to the holes located in the unit base rail (two
holes at each corner). Refer to the installation instructions
for the proper rigging technique.
CAUTION
As with any mechanical equipment, contact with
sharp sheet metal edges can result in personal
injury. Take care while handling this equipment and
wear gloves and protective clothing.
WARNING
installation,
Improper
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.
WARNING
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or maintenance, turn the
electrical power to unit OFF at disconnect
switch(es). Unit may have multiple power
supplies.
UNIT INFORMATION UNIT INFORMATION
Ultra High Efficiency LGM036U through 074U
adjustment, alteration,
100038
02/2022
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
Electrostatic
electronic components. Take precautions
to neutralize electrostatic charge by
touching your hand and tools to metal
prior to handling the control.
Options . . . . . . . . . . . . . . . . . . . . . . . Page 2
Specifications . . . . . . . . . . . . . . . . . . Page 5
High Altitude . . . . . . . . . . . . . . . . . . . Page 6
Blower Data . . . . . . . . . . . . . . . . . . . Page 7
Electrical Data . . . . . . . . . . . . . . . . Page 12
I Unit Components . . . . . . . . . . . . . Page 15
II Placement and Installation . . . . . Page 32
III Start Up Operation . . . . . . . . . . . Page 32
IV Charging . . . . . . . . . . . . . . . . . . . Page 33
V System Service Checks . . . . . . . Page 34
VI Maintenance . . . . . . . . . . . . . . . . Page 36
VII Accessories . . . . . . . . . . . . . . . . Page 38
VIII Diagrams . . . . . . . . . . . . . . . . . . Page 47
Page 1
LGM SERIES
3 to 6 ton
CAUTION
discharge

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can affect