Lennox G40DF Series

Page 1
10/09
*2P1009*
505,253M
*P505253M*
E 2006 Lennox Industries Inc.
Dallas, Texas, USA
THIS MANUAL MUST BE LEFT WITH THE
HOMEOWNER FOR FUTURE REFERENCE
INSTALLATION
INSTRUCTIONS
G40DF(X) Series
GAS FURNACE
505,253M
10/2009
Supersedes 05/2009
Table of Contents
G40DF(X) Unit Dimensions 2. . . . . . . . . . . . . . . . . . . . . . .
G40DF(X) Parts Arrangement 3. . . . . . . . . . . . . . . . . . . . .
G40DF(X) Gas Furnace 4. . . . . . . . . . . . . . . . . . . . . . . . . .
Shipping and Packing List 4. . . . . . . . . . . . . . . . . . . . . . . .
Safety Information 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Use Furnace as a Construction Heater 5. . . . . . . . . . . . .
Combustion, Dilution, & Ventilation Air 6. . . . . . . . . . . . .
Downflow Installation 8. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting Equipment 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filters 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Duct System 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Venting 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gas Piping 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unit Start−Up 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gas Pressure Adjustment 24. . . . . . . . . . . . . . . . . . . . . . .
High Altitude Information 25. . . . . . . . . . . . . . . . . . . . . . . .
Other Unit Adjustments 25. . . . . . . . . . . . . . . . . . . . . . . . . .
Blower Performance 26. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service 28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Planned Service 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Repair Parts List 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ignition Control Board Diagnostic Codes 31. . . . . . . . . . .
Troubleshooting 32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
G40DF(X) Start−Up & Performance Check List 35. . . . . .
WHAT TO DO IF YOU SMELL GAS:
Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other ap-
pliance.
Installation and service must be
performed by a qualified installer,
service 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 supplier’s
instructions.
D If you cannot reach your gas supplier, call
the fire department.
FIRE OR EXPLOSION HAZARD.
Failure to follow safety warnings exact-
ly could result in serious injury, death,
or property damage.
WARNING
D Leave the building immediately.
Litho U.S.A.

Lennox G40DF Series Specifications

General

Brand	Lennox
Model	G40DF Series
Category	Furnace
Language	English

Summary

G40 DF(X) Unit Dimensions - inches (mm)

G40 DF(X) Parts Arrangement

G40 DF(X) Gas Furnace

Shipping and Packing List

Lists items included in the furnace package and those available separately.

Safety Information

Provides essential safety warnings and guidelines for installation and operation.

Use of Furnace as Construction Heater

General

Fiberglass Wool Warning

Warns about exposure to fiberglass wool and its health risks.

Combustion, Dilution, & Ventilation Air

Unconfined Space Air Requirements

Details air requirements for furnaces installed in unconfined areas.

Confined Space Air Requirements

Details air requirements for furnaces installed in confined areas.

Downflow Installation

Installation on Noncombustible Flooring

Instructions for installing the furnace on noncombustible flooring, including opening sizes.

Installation on Combustible Flooring

Instructions for installing the furnace on combustible flooring using an additive base.

Installation on Cooling Cabinet

Return Air Opening - Downflow Units

Filters

Duct System

Return Air Plenum

Discusses requirements for the return air plenum to prevent combustion gas issues.

Venting

Venting Using a Masonry Chimney

Common Venting Using Tile-Lined Interior Masonry Chimney and Combined Vent Connector

General Venting Requirements

Removal of the Furnace from Common Vent

Gas Piping

Gas Supply

Details on connecting the gas supply, including pipe sizing and factors to consider.

Leak Check

Electrical

ELECTROSTATIC DISCHARGE (ESD) Precautions and Procedures

Precautions to protect electronic components from electrostatic discharge during installation and service.

Indoor Blower Speeds

Typical G40 DF(X) Field Wiring Diagram

Integrated Control Board (Automatic Hot Surface Ignition System)

G40 DF(X) Typical Schematic Wiring Diagram

Unit Start-Up

Gas Valve Operation (Figures 22, 23, and 24)

Explains how to operate the gas valve for unit start-up and safety.

Heating Sequence of Operation

Gas Pressure Adjustment

Gas Flow (Approximate)

Details how to measure and interpret gas flow rate for unit performance.

High Altitude Information

Other Unit Adjustments

Primary and Secondary Limits

Describes the location and factory settings of primary and secondary limit controls.

Flame Rollout Switches (Two)

Explains the location and function of flame rollout switches.

Pressure Switch

Details the function of the pressure switch for combustion air induction.

Temperature Rise

Explains how to adjust blower speed to achieve the correct temperature rise.

Fan Control

Discusses adjustable fan off delay settings for comfort.

Thermostat Heat Anticipation

Guidance on setting the thermostat's heat anticipator based on amp draw.

Electrical

Checks for loose connections, correct voltage, and blower motor amp draw.

Blower Speeds

Instructions for selecting and connecting blower speed taps for desired airflow.

Electronic Ignition

Describes the integrated ignition control with internal Watchguard feature.

Flue And Chimney

Failure To Operate

Blower Performance

Lists common issues to check when the blower is not operating correctly.

Service

Blower

Instructions for cleaning the blower wheel and checking motor lubrication.

Filters

Guidelines for inspecting, cleaning, or replacing furnace filters.

Flue And Chimney

Checks for tightness, blockages, and proper connection of flue and chimney.

Electrical

Checks for loose wiring, correct voltage, and blower motor amp draw.

Cleaning the Heat Exchanger and Burners

Detailed steps for cleaning the heat exchanger and burners.

Planned Service

Repair Parts List

Ignition Control Board Diagnostic Codes

Troubleshooting: Heating Sequence of Operation

Troubleshooting: Cooling Sequence of Operation

Troubleshooting: Continuous Fan Sequence of Operation

G40 DF(X) Start-Up & Performance Check List