Lennox EL297UH090XV36C User Manual

Page 1
UNIT INFORMATIONUNIT INFORMATION
Service Literature
©2016 Lennox Industries, Inc.
WARNING
Improper installation, adjustment, alteration,
service or maintenance can cause property damage,
personal injury or loss of life. Installation and service
must be performed by a licensed professional HVAC
installer (or equivalent), service agency or the gas
supplier.
CAUTION
As with any mechanical equipment, contact with
sharp sheet metal edges can result in personal
injury. Take care while handling this equipment and
wear gloves and protective clothing.
EL297UHV(X) series units are 90% e󰀩ciency gas furnac-
es used for upow or horizontal applications only, man-
ufactured with Lennox Duralok heat exchangers formed
of aluminized steel. EL297UHV(X) units are available in
heating capacities of 44,000 to 132,000 Btuh and cooling
applications up to 5 tons. Refer to Product Specications
Manual for proper sizing.
Units are factory equipped for use with natural gas. Kits
are available for conversion to LPG operation. EL297UH-
V(X) model units are equipped with the icomfort
®
enabled
SureLight
®
two-stage variable speed integrated control.
EL297UHV(X) unit meets the California Nitrogen Oxides
(NOx) Standards and California Seasonal E󰀩ciency re-
quirements. All units use a redundant gas valve to assure
safety shut-o󰀨 as required by C.S.A.
All specications in this manual are subject to change.
Procedures outlined in this manual are presented as a
recommendation only and do not supersede or replace lo-
cal or state codes. In the absence of local or state codes,
the guidelines and procedures outlined in this manual (ex-
cept where noted) are recommendations only and do not
constitute code.
TABLE OF CONTENTS
Specications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2
Blower CFM Data . . . . . . . . . . . . . . . . . . . . . . . . . Page 5
I Unit Components . . . . . . . . . . . . . . . . . . . . . . . Page 26
II Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 57
III Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 79
IV Heating System Service Checks . . . . . . . . . Page 80
V Typical Operating Characteristics . . . . . . . . . Page 83
VI Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . Page 83
VII Wiring and Sequence of Operation . . . . . . Page 86
Program Unit Capacity Size Mode . . . . . . . Page 110
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . Page 111
EL297UHV(X)
100088
Communicating-ENABLED EL297UHV SERIES UNITS

Lennox EL297UH090XV36C Specifications

General

Model	EL297UH090XV36C
Type	Gas Furnace
Efficiency Rating	97% AFUE
Heating Capacity	90, 000 BTU/h
Blower Motor	Variable Speed
Fuel Type	Natural Gas
Stages	2-Stage
Warranty	Limited Lifetime Heat Exchanger warranty

Summary

I- Unit Components

Control Box and Integrated Control

Ignition Control Diagnostic Modes

LED Display, Push Button Operations, and Modes

Describes LED codes, push button usage, and modes like Error Recall, Flame Signal, and Unit Size.

Unit Capacity/Size and Soft Disable Modes

Details procedures for programming unit size and understanding the soft disable status.

Ignition Control Diagnostic Codes

Code Descriptions and Recovery Actions

Lists error codes, their status, and required actions for clearing and recovery.

DIP Switch Settings and On-Board Links

Heating Operation DIP Switch Settings

Indoor Blower Operation DIP Switch Settings

B- Indoor Blower Motor

Blower Drive and Motor Components

Troubleshooting Motor Windings

Resistance and Drive Compatibility Tests

Outlines tests to check motor winding resistance and compatibility with the blower drive.

C- Heating Components

Ignitor, Flame Sensor, Gas Valve, and Limits

Ignitor Check Procedures

Resistance and Voltage Testing Steps

Step-by-step guide for checking ignitor resistance and voltage supply.

Combustion Air Inducer System

Inducer, Orifice Sizes, and Pressure Switch

Pressure Switch Check Procedure

Provides steps to test pressure switch differential using a manometer.

II- Placement and Installation

Horizontal Offset and Termination Requirements

Vent Pipe Connections and Clearances

Typical Exhaust/Intake Connections and Termination Clearances

Condensate Piping

Trap Installation and Drain Routing

III- START-UP

Preliminary Checks and Heating Start-Up

Covers pre-start-up checks, initiating heating, and gas valve operation.

Failure To Operate Troubleshooting

Lists common issues and checks for when the unit fails to operate correctly.

IV- HEATING SYSTEM SERVICE CHECKS

Gas Piping, Pressure, and Combustion Checks

Covers gas supply checks, manifold pressure testing, and proper combustion analysis.

I- Proper Ground and Voltage

AC Voltage Checks for Integrated Control

Guides on measuring AC voltage at the integrated control for proper grounding and operation.

VI- MAINTENANCE

Heat Exchanger and Burner Cleaning Procedures

VII- Wiring and Sequence of Operation

EL297UHV Unit Wiring Diagrams

Provides detailed wiring schematics for various furnace models.

Electronic Ignition and Sequence of Operation

Heating Sequence Diagrams

Illustrates heating operation sequences for different thermostat types.

Field Wiring and Configuration

Thermostat and Accessory Wiring

DIP Switch Settings and On-Board Links

Guide for configuring system options using DIP switches and on-board links for various thermostat setups.

IX- Program Unit Capacity Size Modes

Unit Size Configuration Procedure

Troubleshooting Heating Sequence

Heating Sequence Flowcharts for Diagnosis

Visual guides for diagnosing heating operation issues based on sequence steps.

Troubleshooting Cooling Sequence

Cooling Sequence Flowchart for Diagnosis

Visual guide for diagnosing cooling operation issues based on sequence steps.