Lennox LGA120 User Manual

10/08
*2P1008*
504,875M
*P504875M*
LGA/LGC036, 042, 048, 060, 072
LGA/LGC090, 102, 120, 150,
LGA/LGC156, 180, 210, 240, 300S
LGA/LGC248, 300H, 360
©2006
Litho U.S.A.
504,875M
10/2008
Supersedes 1/2006
WHAT TO DO IF YOU SMELL GAS:
FIRE OR EXPLOSION HAZARD
Failure to follow safety warnings ex-
actly could result in serious injury
death or property damage.
WARNING
Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.
Installation and service must be per-
formed by a qualified installer, ser-
vice agency or the gas supplier.
D Do not try to light any appliance.
D Do not touch any electrical switch; do not
use any phone in your building.
D Immediately call your gas supplier from a
neighbor’s phone. Follow the gas suppli-
er’s instructions.
D If you cannot reach your gas supplier, call
the fire department.
D Extinguish any open flames.
ROOFTOP
UNITS
READ ALL INSTRUCTIONS IN THIS MANUAL
AND RETAIN FOR FUTURE REFERENCE
LGA240 SHOWN
See unit nameplate for manufacturer
and address.
FBR113270
(3, 3−1/2, 4, 5, and 6 TONS)
(7−1/2, 8-1/2, 10, and 12-1/2 TONS)
(13, 15, 17-1/2, 20, and 25 TONS)
(20, 25, and 30 TONS)
D Leave the building immediately.

Lennox LGA120 Specifications

General

Brand	Lennox
Model	LGA120
Category	Air Conditioner
Language	English

Summary

Safety Information

General Unit Safety

Keep unit area clear of combustibles and ensure unobstructed airflow for combustion and ventilation.

Electrical & Explosion Hazards

Warnings regarding electrical shock, explosion, fire, and dangers from improper servicing or wet components.

Fiberglass Wool Safety

Information on fiberglass wool exposure risks, including potential cancer and irritation, and how to reduce exposure.

Unit Operation Safety

Safety measures before lighting the unit and general operational safety guidelines, including ignition system details.

Unit Startup Procedures

Gas Valve Operation Steps

Detailed instructions for operating gas valves (White Rodgers 36E, Honeywell VR8205M/VR8305Q) during unit startup.

Turning Off Gas Supply

Procedures for safely turning off the gas supply to the furnace, including thermostat and power considerations.

Inspection and Service

Burner Flame Inspection

Guidelines for inspecting the burner flame to ensure proper unit operation, including flame characteristics.

Flue & Vent Inspection

Annual inspection of combustion air louvers, vent cap, heat exchanger, and burners for corrosion or debris.

Annual Service Requirement

Requirement for yearly servicing by a qualified technician to maintain efficiency and warranty.

Component Maintenance

Filter Replacement and Servicing

Instructions for checking and replacing filters monthly, noting air flow direction during reinstallation.

Burner Cleaning Procedures

Procedure for cleaning burners, including removing them, cleaning, and checking the spark gap on the ignition electrode.

Blower Bearing Lubrication

Information on lubricating blower shaft bearings every two years with specific lithium base grease.

Manifold Pressure Specifications

Reference to tables and figures for manifold pressure specifications and location of pressure ports.

System Maintenance and Parts

Combustion Air Inducer Cleaning

Steps to clean the combustion air inducer wheel and housing, including disconnecting tubing and securing screws.

Flue Box and Tube Cleaning

Instructions for cleaning the flue box and tubes using a wire brush after removing the inducer assembly.

Pre-Service Checklist

A checklist of common issues to verify before calling a service technician for an inoperative unit.

Ordering Repair Parts

Guidance on ordering repair parts, emphasizing the need for complete model and serial numbers.