Lennox G20 Series - User Manual

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PRODUCT LITERATURE
Litho U.S.A.
502,754M
9/98
Supersedes 4/95
¤ 1992 Lennox Industries Inc.
Dallas, Texas
*$6 )851$&(
Installation and service must be per-
formed by a qualified installer, ser-
vice agency or the gas supplier.
- Do not try to light any appliance.
- Do not touch any electrical switch; do not
use any phone in your building.
- Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.
- If you cannot reach your gas supplier, call
the fire department.
- Extinguish any open flames.
Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.
If the information in this manual is not
followed exactly, a fire or explosion
may result causing property damage,
personal injury, or death.
:$51,1*

Summary

Product Identification and Safety Information

Parts Identification

Identifies the major components of the G20E/G20X series gas furnace.

General Safety Warnings

Crucial safety information regarding fire, explosion, and property damage risks.

Carbon Monoxide Hazard

Details the dangers of carbon monoxide gas and recommended precautions.

Lighting and Operation

Lighting and Operation Instructions

Provides instructions for lighting the furnace and operating the gas valve.

Turning Off Gas Supply

Step-by-step guide on how to safely turn off the gas supply to the unit.

Maintenance and Service

Filter Maintenance

Instructions for inspecting, cleaning, and replacing furnace filters.

Venting System Inspection

Guidance on annual inspection of the furnace venting system.

Blocked Vent Shut-Off System

Explanation of the safety system that detects vent blockages.

Service Reminders and Precautions

Key checks before calling for service and general safety precautions.

Overview

1. Function Description
2. Usage Features
3. Maintenance Features

This document is a user's information manual for the Lennox G20 Series Gas Furnace, specifically covering the G20E and G20X models. It provides comprehensive instructions for safe operation, maintenance, and troubleshooting of the appliance.

Function Description

The Lennox G20 Series Gas Furnace is a heating appliance designed to provide warmth for residential spaces. It operates by burning natural gas or propane to heat air, which is then circulated throughout the building via a duct system. The furnace features an intermittent pilot ignition system, meaning the pilot light automatically ignites when the thermostat calls for heat, eliminating the need for manual lighting. This design ensures that the pilot does not burn continuously when there is no demand for heat, contributing to energy efficiency. The furnace is equipped with various safety features, including a blocked vent shut-off switch and a flame roll-out switch, which automatically cut off the gas supply in the event of flue or vent blockage or if flame roll-out occurs, preventing potential hazards such as fire or carbon monoxide poisoning.

Usage Features

The manual emphasizes several critical usage features to ensure safe and efficient operation:

• Gas Valve Operation: Detailed instructions are provided for turning the gas valve ON and OFF, which is crucial for starting and shutting down the furnace. Users are cautioned to never force the gas control knob or lever and to avoid using tools, as this could lead to a fire or explosion. A five-minute waiting period is recommended after turning off the gas to allow any residual gas to clear before attempting to restart, with a strong warning to call the gas supplier immediately if gas is smelled during this period.
• Thermostat Control: The furnace's operation is controlled by a thermostat. Users are instructed to set the thermostat to the lowest setting before performing any service or turning off the unit and to the desired setting for normal operation.
• Automatic Ignition: The G20 Series furnaces are equipped with an automatic ignition device, eliminating the need for manual pilot lighting. This simplifies the startup process for the user.
• Safety Precautions: The manual highlights several safety precautions, including not storing or using flammable vapors and liquids near the appliance, ensuring unobstructed airflow for combustion and ventilation, and avoiding the introduction of chlorine or fluorine products into the combustion air, as these can cause furnace corrosion.
• Return Air Management: A critical warning advises against drawing return air from the room where the furnace or any other gas appliance is installed. This is because a negative pressure created in the room can pull flue products back down the vent pipe, leading to incomplete combustion and the formation of toxic carbon monoxide gas, which could then be distributed throughout the house.
• Carbon Monoxide Awareness: The manual stresses the invisible, odorless, and toxic nature of carbon monoxide gas and strongly recommends the use of a carbon monoxide detector in the home as an investment in safety, even for homes without gas appliances.
• Water Damage Protocol: A specific warning instructs users not to operate the furnace if any part has been under water and to immediately contact a qualified service technician for inspection and replacement of affected control system parts or gas controls.

Maintenance Features

The manual outlines several maintenance features and recommendations to ensure the longevity and safe operation of the furnace:

• Annual Inspection and Maintenance: Lennox strongly recommends an annual inspection and maintenance of the appliance by a qualified service technician. This proactive approach helps detect and address potential issues before they become serious.
• Filter Cleaning and Replacement: The G20 Series units are equipped with reusable filters that should be inspected monthly and cleaned as necessary. Detailed instructions are provided for turning off electrical power, removing the blower access panel, sliding out the filter, washing it with water and mild detergent, and optionally spraying it with filter Handicoater for increased efficiency. Specific part numbers are provided for replacement filter media if needed, with a note to not replace reusable foam filters with throw-away filters.
• Blower Maintenance: Users are advised to check and clean the blower wheel for any debris. The blower motor is prelubricated for extended bearing life, requiring no further lubrication from the user.
• Pilot and Burner Flame Inspection: Periodic checks of the pilot flame and burner flame are crucial for proper operation. The pilot flame must surround the end of the flame sensor for the pilot safety circuit to function correctly. The burner flame should be predominantly blue, strong in appearance, and rise directly from the burner ports, burning from all continuous ribbon ports without impinging on the sides of the heat exchanger.
• Venting System Inspection: An annual inspection of the furnace venting system, draft hood, vent cap, heat exchanger, burners, and pilot for corrosion, deterioration, or debris is recommended before the heating season. Any obstructions should be removed.
• Blocked Vent Shut-Off System: The furnace includes a blocked vent shut-off switch and a flame roll-out switch as safety mechanisms. If these switches activate, the gas supply to the furnace is cut off. Users are explicitly warned not to attempt to place the furnace back into operation if these switches have functioned and to contact a qualified service person.
• Service Reminder and Troubleshooting: The manual provides a service reminder checklist for users to review if the unit is inoperative, covering checks such as electrical disconnect switches, thermostat setting, fuses/circuit breakers, gas valve position, air filter condition, and gas supply.
• Signs of Malfunction: Users are encouraged to pay attention to their furnace and look for signs of malfunction, such as unusual noises, odors, visible condensate on windows, burnt components, or dirt/rust accumulations on the vent pipe or unit. Experiencing symptoms like headache, nausea, fatigue, or dizziness, especially if they subside away from home, could indicate carbon monoxide exposure. In such cases, immediate shutdown of the unit and contact with an independent Lennox dealer are advised.
• Planned Service Items: For a planned annual inspection, a service technician is expected to check various components, including fresh air grilles and louvers, burners, vent pipe, unit appearance, blower access door, return air duct, operating performance, and combustion gases. Power to the unit must be shut off for the technician's safety during these checks.

Overall, the manual serves as a vital resource for owners of the Lennox G20 Series Gas Furnace, providing essential information for safe operation, routine maintenance, and recognizing when professional service is required.

Lennox G20 Series Specifications

General

Model	G20 Series
Ignition System	Direct Spark Ignition
Vent Type	Natural Draft
Warranty	Limited Lifetime Heat Exchanger, 5-year Parts
Fuel Type	Natural Gas or Propane