Lennox LGC360H2B

© 1999 Lennox Industries Inc.
Litho U.S.A.
Page 1
Corp. 9913−L7
LGA/LGC
LCA/LCC
Service Literature
21 / 30 TON
74 / 105 kW
Revised 01−2009
LGA/LGC/LCA/LCC SERIES
The LGA /LGC/ LCA/LCC 21, 25 and 30 ton (74, 88, 105 kW)
units are configured to order units (CTO) with a wide selection
of factory installed options. The LGA/LGC248H/360H gas/
electric packaged rooftop units are available in 260,000 Btuh,
360,000 Btuh and 480,000 Btuh (76.2 kW, 105.5 and 137.7
kW) heating inputs. Gas heat sections are designed with Len-
nox’ aluminized steel tube heat exchangers. The LCA/
LCC248H/360H cooling packaged rooftop units are
equipped with the same cooling sections as the LGA/
LGC248H/360H units.
LCA/LGA248, LCC/LGC300H and LCC/LGC360H units
may contain a supply air blower equipped with a variable
frequency drive A96 (VFD) which varies supply air CFM. As
duct static increases, the supply air volume will decrease.
As duct static decreases, the supply air volume will in-
crease.
Optional electric heat is factory−or field−installed in LCA /LCC
units. Electric heat operates in single or multiple stages de-
pending on the kW input size. 30kW through 120kW heat
sections are available for the LCA/LCC248H/360H. LGA/
LGC and LCA/LCC units have identical refrigerant circuits
with 21, 25 and 30 ton (74, 88 and 105kW) cooling capaci-
ties. LGA/LCA360H units utilize three compressors, while
the LGA/LCA300H and LGA/LCA248H units utilize four
compressors.
Units are also designed for R−410A refrigerant. See unit
nameplate for refrigerant type and charge. Operating pres-
sures and pressure switch settings are significantly higher
than units charged with R−22. Service equipment for
R−410A units must be rated for R−410A refrigerant.
The LGA and LCA units are designed to accept any of sev-
eral different energy management thermostat control sys-
tems with minimum field wiring. Factory or field provided
control options connect to the unit with jack plugs. When
"plugged in" the controls become an integral part of the unit
wiring.
Information contained in this manual is intended for use by
qulified service technicians only. All specifications are sub-
ject to change. Procedures outlined in this manual are pre-
sented as a recommendation only and do not supersede 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 prop-
er rigging technique.
LGA360
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person-
al injury or loss of life. Installation and service must
be performed by a qualified installer or service
agency.
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 discon-
nect switch(es). Unit may have multiple
power supplies.

Lennox LGC360H2B Specifications

General

Brand	Lennox
Model	LGC360H2B
Category	Air Conditioner
Language	English

Summary

LGALCA Specifications

Cooling Performance Details

Details of cooling capacity, airflow, and efficiency ratings for LGA/LCA units.

LGCLCC Specifications

Gas Heating Performance Details

Specifications for gas heating input, output, thermal efficiency, and gas supply.

Gas and Electric Heat Specifications

Electric Heat Capacity Data

Tables detailing electric heat capacities based on kW input and voltage.

Electrical Component Data

Electrical specifications for compressors, fans, and motors.

LGALCA Electrical and Electric Heat Data

LGCLCC Electrical and Electric Heat Data

Compressor Electrical Ratings

Rated and locked rotor amps for compressors across various voltages.

Fan Motor Electrical Ratings

Electrical data for outdoor fan motors, including horsepower and amps.

Minimum Circuit Ampacity Requirements

Minimum circuit ampacity requirements for electric heat sections.

Maximum Overcurrent Protection Settings

Maximum overcurrent protection ratings for electric heat sections.

Optional Unit Accessories

Electric Heat Options

Accessories related to electric heat, including control modules and fuse blocks.

Outdoor Air Dampers and Economizer System

Economizer Options

Optional Electric Heat Accessories

Electric Heat Control Module and Fuse Blocks

Details on electric heat control modules and fuse blocks for various unit models.

LTB2 Electric Heat Terminal Block

Control Box Components

Unit Components

Electrostatic Discharge (ESD) Precautions

Blower, Fan Relays, and Combustion Air Controls

Electric Heat and IMC Board Components

Components for electric heat and the Integrated Modular Control system.

Control Box Components Overview

Description of various control box components like transformers, relays, and contactors.

Burner and Motor Controls

IMC Board Operation

IMC Board Inputs, Outputs, and Locations

Diagrams of IMC board connections and locations of add-on modules.

Cooling Components

Compressors, Crankcase Heaters, and Pressure Switches

Information on compressors, heaters, high pressure, and ambient switches.

Low Pressure Switches and Service Valves

Low Ambient Switches and Controls

Details on low ambient switches and their function in cooling.

Filter Driers and Freezestats

Blower Operation and CFM Determination

Determining Unit CFM

CAV and VAV Blower Speed Adjustments

Blower Assembly and Belt Adjustment

Blower Assembly Diagram and CFM Adjustment

Belt Tension and Pulley Alignment

Gas Heat Components

Gas Heat System Overview and Controls

Heat Exchanger Functionality

Primary High Temperature Limits

Flame Rollout Limits and Prove Switches

Gas Valves, Spark Electrodes, and Flame Sensors

Description of gas valves, spark electrodes, and flame sensor operation.

Gas Flow, Burner, and Electrode Maintenance

Burner Ignition Control Operation

Details on the burner ignition control module and its sequence.

Burner Assembly and Flame Sensing

Secondary High Temperature Limits

Combustion Air Inducers and Capacitors

Heat Exchanger and Flame Sensing

Optional Electric Heat Components

Electric Heat Section Placement and Controls

Placement of electric heat sections and main control box components.

High Temperature Limits and Element Control

Details on temperature limits and heating element control.

Terminal Strips, Fuses, and Heating Elements

Placement and Installation

Startup, Operation, and Charging Procedures

Procedures for unit startup, operation, and refrigerant charging.

Preliminary Checks Before Startup

Cooling Start-Up and System Checks

Steps for initiating cooling operation and checking system parameters.

Refrigerant Handling and Charge Verification

R410 A Refrigerant Safety and Handling

Safety guidelines and handling procedures for R410A refrigerant.

Refrigerant Charge Verification Methods

Methods for verifying and checking refrigerant charge using approach temperature.

Heating Start Up Procedures

Safety Precautions Before Lighting

Safety guidelines and warnings before lighting the unit.

Systems Service Checks

Gas Piping Installation and Testing

Procedures for gas piping installation, leak testing, and pressure checks.

Gas Supply Pressure Testing and Adjustment

System Service Checks

Cooling System Service Checks

Control Systems

Thermostat and Smoke Detector Options

Blower, IAQ, and LP Gas Options

Blower Operation and VFD

Supply Air VFD Operation and Bypass

Wiring Diagrams and Operation Sequence

Sequence of Operation - Cooling

Power and Blower Initialization

Economizer and First Stage Cooling

Second Stage Cooling and End of Stage

Steps for second stage cooling and actions at stage completion.

Sequence of Operation - Heating

First Stage Heating Activation

Steps for initiating first stage heating operation.

Second Stage Heating Activation

Steps for initiating second stage heating operation.

Low Ambient Kit and End of Stage Sequences

Sequence of Operation - Electric Heat

Heating Elements Activation

First and Second Stage Heating Sequences

Detailed steps for first and second stage heating activation.

End of Heating Stage Sequences

Thermostat Operation Sequence

Thermostat Wiring and Power Connections

Thermostat Operation Logic and Data Flow

Logic flow for thermostat operation and control module interaction.

Economizer Operation Sequence

Economizer Wiring and Power Supply

Economizer Operation Logic and Damper Control

Logic flow for economizer operation and damper control.