Lennox G26 Series User Manual

Page 28
III−START-UP
A−Preliminary and Seasonal Checks
1 − Inspect electrical wiring, both field and factory installed
for loose connections. Tighten as required.
2 − Check voltage at disconnect switch. Voltage must be
within range listed on the nameplate. If not, consult the
power company and have voltage condition corrected
before starting unit.
3 − Inspect condition of condensate traps and drain as-
sembly. Disassemble and clean seasonally.
B−Heating Start-Up
FOR YOUR SAFETY READ BEFORE LIGHTING
CAUTION
Shock and burn hazard.
G26 units are equipped with the SureLight ignition
system. Do not attempt to light manually.
WARNING
Do not use this furnace if any part has been under-
water. Inspect the furnace and replace any part of
the control system and any gas control which has
been under water.
WARNING
If overheating occurs or if gas supply fails to shut
off, shut off the manual gas valve to the appliance
before shutting off electrical supply.
CAUTION
Before attempting to perform any service or main-
tenance, turn the electrical power to unit OFF at
disconnect switch.
BEFORE LIGHTING smell all around the appliance area
for gas. Be sure to smell next to the floor because some
gas is heavier than air and will settle on the floor.
Use only your hand to push in or turn the gas control knob.
Never use tools. If the knob will not push in or turn by hand,
do not try to repair it, call a qualified service technician.
Force or attempted repair may result in a fire or explosion.
G26 units are equipped with the SureLight ignition system.
DO NOT attempt to manually light burners on this furnace.
Each time thermostat calls for heat, burners will be automati-
cally lit. The ignitor does not get hot when there is no call for
heat on units with SureLight ignition system.
How To Operate Gas Valve (Figure 43)
WARNING
If you do not follow these instructions exactly, a
fire or explosion may result causing property
damage, personal injury or loss of life.
1 − STOP! Read the safety information at the beginning of
this section.
2 − Set thermostat to lowest setting.
3 − Turn off all electrical power to furnace.
4 − This appliance is equipped with an ignition device
which automatically lights the burner. Do not try to
light the burner by hand.
5 − Remove unit access panel.
6 − On Honeywell VR8204 gas valves, turn knob on gas
valve clockwise to OFF. For White Rodgers 36E
gas valves, move switch to OFF. Do not force. See fig-
ure 43.
ON
OFF
FIGURE 43
HONEYWELL VR8204 SERIES GAS VALVE
GAS VALVE SHOWN IN OFF POSITION
WHITE RODGERS
36E GAS VALVE
GAS VALVE
SHOWN
IN OFF
POSITION
7 − Wait five (5) minutes to clear out any gas. If you then
smell gas, STOP! Immediately call your gas supplier
from a neighbor’s phone. Follow the gas supplier’s in-
structions. If you do not smell gas go to next step.
8 − For Honeywell VR8204 gas valves, turn knob on
valve counterclockwise to ON. For White
Rodgers 36E gas valves, move switch to ON.
9 − Replace unit access panel.
10− Turn on all electrical power to unit.
11− Set thermostat to desired setting.
NOTE−When unit is initially started, steps 1 through 11
may need to be repeated to purge air from pilot line.

Lennox G26 Series Specifications

General

Heating Stages	Single-stage
Blower Motor	PSC (Permanent Split Capacitor)
Gas Valve	Single-stage
Vent Type	Natural Draft
Fuel Type	Natural Gas or Propane
Blower Motor Type	PSC
Warranty	5-Year Limited Warranty on covered components
Heating Capacity	44, 000 to 132, 000 BTU/h
Filter Type	Standard

Summary

G26 Series Units Overview

Combustion Process

Detailed explanation of the furnace's combustion cycle, from air intake to flue exhaust.

Furnace Specifications

Optional Accessories

List of optional accessories available for the G26 series furnaces.

Blower Performance Data

Filter Air Resistance

Data on air resistance caused by filters at various airflow rates.

Venting and Gas Pipe Capacity

Intake and Exhaust Pipe Venting Table

Specifies minimum vent pipe diameters based on equivalent length and furnace capacity.

G26-3 Through -6 Components

G26 Heat Exchanger and Parts Orientation

G26 General Parts Orientation

Diagram illustrating the general layout and location of major components within the G26 furnace.

Unit Components and Controls

Make-Up Box Installation

Instructions and diagrams for installing the electrical make-up box.

Internal Unit Components

Burners and Ignition System

Details on furnace burners, SureLight ignition system, and related safety components.

SureLight Control Board and Diagnostics

Diagnostic Codes

Table and explanation of LED diagnostic codes for troubleshooting the SureLight control board.

SureLight Control Terminals and Ignition Features

Electronic Ignition and Fan Time Control

Information on electronic ignition operation and adjustable fan off-time settings.

Blower Ratings and System Controls

Combustion Air Blower Operation

Details on the function and operation of the combustion air blower (B6).

Ignition Control A3 and Terminals

Ignition Control A3 Terminal Designations

Table listing the terminals and their functions for the Ignition Control A3.

Diagnostic LED and Ignition Control Operation

Johnson G776 Ignition Control Operation

Description of the ignition control's operation sequence for heating mode.

Burner Pilot/Electrode Orientation and Gas Valve

100% Sealed Combustion

Explanation of the sealed combustion system and its pressure-sensing capabilities.

Differential Pressure Switch Operation

Differential Pressure Switch Circuitry

Diagram illustrating the electrical connections of the differential pressure switch.

Measuring Pressure Differential

Venting Considerations and Pipe Cementing

Venting Considerations

Guidance on proper venting practices and material selection to ensure safe operation.

Intake and Exhaust Piping Installation

Removal of Unit from Common Venting System

Procedure for safely removing a unit from a shared venting system.

Vent Termination Illustrations

Roof Termination Kit

Details and figures for roof termination kits used with G26 furnaces.

Wall and Rooftop Termination Details

Concentric Wall Termination

Diagram and specifications for concentric wall termination kits.

Wall Termination Kit Details

Wall Termination Kit (30G28) WTK

Information on the WTK wall termination kit, including side and top views.

Vent Termination Configurations

G26 Venting in Existing Chimney

Instructions for venting the G26 furnace within an existing chimney system.

Condensate Piping and Assembly

Condensate Assembly Details

Diagrams and procedures for connecting the condensate trap and drain line.

Condensate Removal Process (G26-3 to -6 Models)

Detail of Cold Header Condensate Trap

Close-up views and explanation of the cold header condensate trap.

Furnace Start-Up Procedures

Heating Start-Up

Step-by-step instructions for safely starting the furnace in heating mode.

Heating System Service Checks

Exhaust CO2 and CO Content

Guidelines for checking exhaust gas composition (CO2 and CO) for proper combustion.

Gas Supply Pressure Testing

Check Manifold Pressure

Procedure for checking and adjusting manifold pressure for proper gas valve operation.

Gas Flow Measurement and Flame Signal

To Measure Flame Signal

Instructions for measuring the flame signal using a voltmeter and transducer.

Typical Operating Characteristics and Blower Adjustment

Blower Speed Taps Leadless Motors

Guide for selecting blower speeds on leadless motor models.

Blower Speed Charts and Maintenance

Filters

Recommendations for inspecting, cleaning, or replacing air filters.

Heat Exchanger and Burner Cleaning Procedures

Cleaning Heat Exchanger and Burners

Detailed steps for disassembling and cleaning the heat exchanger and burners.

Burner Box Removal and Cleaning

Cleaning the Burner Assembly

Instructions for cleaning the burner assembly, including cover removal and manifold access.

Component Reassembly and Maintenance Checks

Supply Air Blower Maintenance

Guidance on checking and cleaning the supply air blower motor and housing.

Wiring Diagrams and Thermostat Connections

Field Wiring, Thermostat Connections

Diagrams showing typical field wiring and thermostat connections for G26 units.

G26 Wiring Diagram (-3 & -4 Models)

Heating Sequence of Operation - SureLight Control

Normal Heating Mode Sequence

Flowchart detailing the normal heating sequence of operation for the SureLight control.

Heating Sequence Continued

Abnormal Heating Mode Sequence

Flowchart outlining abnormal heating mode sequences and potential issues.

Cooling Sequence of Operation - SureLight Control

Normal Cooling Mode Sequence

Flowchart detailing the normal cooling sequence of operation for the SureLight control.

Continuous Low Speed Fan Sequence

Heating Sequence of Operation

Step-by-step description of the heating sequence and blower operation.

SureLight Control Troubleshooting Guide

Unit Fails to Operate (Cooling, Heating, Fan)

Troubleshooting steps for unit failure to operate in cooling, heating, or continuous fan modes.

Troubleshooting Unit Operation Failures

Unit Fails to Fire (Combustion Air Blower Not Energized)

Troubleshooting steps when the combustion air blower does not start during heating.

Troubleshooting Fire and Ignition Failures

Unit Fails to Fire (Combustion Air Blower Energized, Ignitor Not)

Troubleshooting steps for ignition failure with combustion air blower energized.

Troubleshooting Premature Unit Shutdowns

Burners Light, Unit Shuts Down Prematurely

Steps for diagnosing premature unit shutdown after burners light.

Troubleshooting Burner and Flame Issues

Burners Light Roughly, Unit Fails to Stay Lit

Procedure for addressing rough burner ignition and flame failure issues.

Troubleshooting Flame Sense and Blower Issues

Low Flame Sense and Indoor Blower Failures

Diagnosing low flame sense signals and indoor blower operation failures.

G26 -1 and -2 Models Wiring and Operation

BCC2 Blower Control Troubleshooting

BCC2 Troubleshooting Flowchart

Flowchart for troubleshooting the BCC2 blower control on -1 and -2 models.

G776 Ignition Control Troubleshooting

Spark Present but Pilot Not Lighting

Troubleshooting steps when spark is present but pilot fails to ignite.

G776 Ignition Control Troubleshooting: No Spark

No Spark and System Will Not Work

Procedure for diagnosing and resolving issues where no spark is generated.

G776 Ignition Control Troubleshooting: Pilot Issues

Pilot Lights but Main Valve Will Not Come On

Steps for troubleshooting when the pilot lights but the main valve remains off.