Lennox LCC Series

© 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 LCC Series Specifications

General

Brand	Lennox
Model	LCC Series
Category	Air Conditioner
Language	English

Summary

Unit Information and Safety Precautions

Series Overview

General introduction to the LGA/LGC/LCA/LCC unit series and their features.

Critical Safety Warnings

Critical warnings regarding installation, service, and electrical hazards.

Unit Specifications

Gas Heat and Electrical Specifications

Gas Heating Performance Details

Electric Heat Capacity Data

Optional Unit Accessories

Optional Unit Accessories (Continued)

Optional Electric Heat Accessories

Electric Heat Control Module Selection Guide

Guide to selecting electric heat control modules based on unit model and kW.

LTB2 Electric Heat Terminal Block Information

Blower Data and Drive Specifications

Blower Data Details

Parts Arrangement Diagrams

Unit Components Overview

Electrostatic Discharge (ESD) Precautions

Control Box Component Descriptions

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

Unit Components (Continued)

Blower, Fan Relays, and Inducer Control Components

Details on blower contactors, outdoor fan relays, and combustion air inducer relays.

Burner Controls and Motor Overload Protection

Information on burner control modules and blower motor overload relays.

Electric Heat and Control Module Information

Electric Heat Control Circuit Components

Details on electric heat relays, transformers, and control modules (A60, A55).

Refrigerant Circuit Diagrams

Plumbing Components

Cooling Components

Compressor and Crankcase Heater Information

High and Low Pressure Switch Operation

Details on high and low pressure switches and their settings for R22/R410A.

Low Ambient Switch Functionality

Cooling Components (Continued)

Low Pressure Switch Operation Details

Blower Operation and CFM Adjustment

Blower Maintenance Procedures

Gas Heat Components

Control Box Components for Gas Heat Systems

Identification of control box components related to gas heat systems.

Burner Ignition Control Operation Sequence

Details on burner ignition controls (A3, A12) and their operation sequence.

Gas Heat Components (Continued)

Heat Exchanger and Burner Assembly Description

High Temperature Limit Switch Functions and Locations

Information on primary and secondary high temperature limit switches (S10, S99, S21, S100).

Flame Rollout Limits and Combustion Air Prove Switches

Description of flame rollout limits (S47, S69) and prove switches (S18, S45).

Gas Valve and Spark Electrode Operation

Information on two-stage gas valves (GV1, GV3) and spark electrode assemblies.

Combustion Air Inducer and Capacitor Details

Flame Sensor Functionality and Location

Optional Electric Heat Components

Electric Heat Control Circuitry Details

Details on electric heat relays, transformers, contactors, and limits for heating sections.

Integrated Modular Control (IMC) Board Functions

Overview of IMC boards for compressors, gas valves, and economizers.

Placement and Installation

Preliminary Installation Checks

Startup, Operation, and Charging

Cooling Start-Up Procedure Steps

Steps for initiating cooling operation and checking system pressures.

Startup, Operation, and Charging (Continued)

R410 A Refrigerant Handling and Charge Verification

Refrigerant Charge Verification Approach Method Details

Detailed approach method for verifying refrigerant charge.

Refrigerant Charge Verification Approach Method

Methods for checking refrigerant charge using approach temperature.

Heating Start-Up Procedure Overview

Safety and operational steps for initiating heating.

Heating Start-Up Procedure (Continued)

Gas Valve Operation and Safety Shutdown Instructions

Instructions for operating gas valves and performing safety shutdowns.

Systems Service Checks (Heating)

Gas Piping and Pressure Testing Procedures

Procedures for testing gas piping and supply/manifold pressures.

Systems Service Checks (Heating) (Continued)

Gas Flow and Burner Component Checks

Procedures for checking gas flow, inshot burners, and spark electrodes.

Heat Exchanger and Flame Sensing Operation

Maintenance Procedures

Filter Inspection and Replacement Guidelines

Electrical Checks and Accessories

Electrical System Checks and Voltage Verification

Accessories Information

Accessories Information (Continued)

Supply Air VFD Operation

Sequence of Operation

Power, Blower, and Cooling Stage Sequences

Wiring Diagrams

Heating-Electric Wiring Diagram (EHA 15-120 kW)

Heating-Electric Wiring Diagram (G, J, M)

Sequence of Operation (Electric Heat)

Electric Heat Stage Sequences and Safety Limits

Step-by-step operation for electric heat stages, including safety limits.

Thermostat Wiring and Sequence

Electronic or Electromechanical Thermostat Wiring

Economizer Operation Sequence

Economizer Wiring and Sequence of Operation