100036

LGM SERIES

Service Literature

7.5 to 12.5 ton

38.1 to 70.3 kW

LGM092U through 1502U

The LGM, 092, 102U, 120U and 150U units are configure to

order units (CTO) with a wide selection of factory-installed

options. Units are available in 130,000 to 240,000 Btuh.

heating inputs. Gas heat sections are designed with alu

minized steel tube heat exchangers with stainless steel as

an option.

Cooling capacities range from 7.5 to 12.5 tons. Units come

standard with a fin tube condenser with two single-speed

compressors plumbed in tandem to form a single refriger

ant circuit. Units also offer mechanical cooling down to

40F.

All units are equipped with direct drive blowers. The blower

will operate at lower speeds when demand is low and in

crease to higher speeds when demand is high.

Variable speed VAV system is available as an option which

enables supply duct static measurement to control blower

CFM and discharge air temperature to control cooling

stages. All LGM units are designed to accept any of several

different energy management thermostat control systems

with minimum field wiring. Factory- or field-provided control

options connect to the unit through Smartwire connectors.

When “plugged in” the controls become an integral part of

the unit wiring.

The CORE Control System is designed to accelerate

equipment install and service. Standard with all Model L™

rooftop units, control system integrates key technologies

that lower installation costs, drive system efficiency, and

protect your investments. The CORE Unit Controller is a

microprocessor-based controller that provides flexible con

trol of all unit functions.

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.

WARNING

Improper installation, adjustment, alteration, service

or maintenance can cause property va, personal in

jury 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

To prevent serious injury or death:

1-Lock-out/tag out before performing maintenance.

2- If system power is required (e.g., smoke detector

maintenance, disable power to blower, remove fan

belt where applicable, and ensure all controllers and

thermostats are Set to the “OFF” position before per

forming maintenance.

3- Always keep hands, hair, clothing, jewelery, tools,

etc.,c away from moving parts.

CAUTION

As with any mechanical equipment, contact with

sharp sheet metal edges can result in personal in

jury. Take care while handling this equipment and

wear gloves and protective clothing.

Table of Contents

Options / Accessories Page 2.....................

Specifications Page 5............................

High Altitude Page 6.............................

Blower Data Page 7.............................

Electrical Data Page 10..........................

I-Unit Components Page 13.......................

II-Placement and Installation Page 37...............

III-Charging Page 37..............................

IV-Start Up - Operation Page 38....................

V-System Service Checks Page 40................

VI-Maintenance Page 42..........................

VII-Accessories Page 43..........................

VIII-Direct Drive Supply Air Inverter Page 49.........

XI-Wiring and Operation Sequence Page 51.........

Lennox LGM120U - Page 22

Table of Contents

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