Lennox Merit ML296UH090XV48C

Page 1
INSTALLATION
INSTRUCTIONS
ML296UHV
507869-02
06/2019
Supersedes 507869-01
THIS MANUAL MUST BE LEFT WITH THE
HOMEOWNER FOR FUTURE REFERENCE
This is a safety alert symbol and should never be
ignored. When you see this symbol on labels or in man-
uals, be alert to the potential for personal injury or death.
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.
© 2019 Lennox Industries Inc.
Dallas, Texas USA
MERIT
®
SERIES GAS FURNACE
UPFLOW / HORIZONTAL AIR DISCHARGE
Contents
Unit Dimensions - inches (mm) ......................................2
ML296UHV Gas Furnace ...............................................3
Shipping and Packing List ..............................................4
Safety .............................................................................3
Use of Furnace as a Construction Heater ......................4
General ...........................................................................5
Combustion, Dilution, Ventilation Air...............................5
Setting Equipment ..........................................................8
Filters ............................................................................13
Duct System ................................................................. 11
Pipe Fittings Specications...........................................14
Joint Cementing Procedure .......................................... 15
Venting Practices ..........................................................16
Gas Piping ....................................................................36
Electrical .......................................................................39
Blower Motor Performance ...........................................42
Integrated Control .........................................................47
Unit Start-Up .................................................................48
Gas Pressure Measurement.........................................49
Proper Combustion.......................................................50
High Altitude .................................................................50
Repair Parts List ...........................................................51
Sequence of Operation.................................................52
Service..........................................................................53
OFF
ON
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HI
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Lennox Merit ML296UH090XV48C Specifications

General

Model	ML296UH090XV48C
Type	Gas Furnace
Efficiency Rating	96% AFUE
Heating Capacity	90, 000 BTU/h
Blower Motor	Variable Speed
Fuel Type	Natural Gas
Stages	Two-Stage
Ignition Type	Hot Surface
Warranty	Limited Lifetime Warranty on Heat Exchanger

Summary

Furnace Overview and Installation Basics

Unit Dimensions

Provides detailed measurements for furnace installation and component placement.

Safety Information

Highlights critical safety warnings, cautions, and hazards related to furnace installation and operation.

Shipping and Packing List

Lists components included with the furnace unit for installation.

Installation Site and Requirements

Installation Locations and Clearances

Details acceptable locations, site requirements, and required clearances for furnace installation.

Combustion, Dilution & Ventilation Air

Guidelines for ensuring adequate air supply and proper venting for safe operation.

Setting Equipment and Duct System

Guides on leveling, positioning, and installing ductwork for the furnace.

Piping and Venting Systems

Pipe & Fittings Specifications

Lists approved materials and standards for gas and vent piping connections.

Venting Practices

Procedures and guidelines for proper installation of exhaust and intake piping systems.

Condensate Piping

Instructions for installing the condensate trap and drain lines for proper drainage.

Gas, Electrical, and Control Systems

Gas Piping Installation

Covers gas supply connection requirements, sizing, and leak testing procedures.

Electrical Wiring and Connections

Details electrical safety precautions, wiring, grounding, and connection diagrams.

Blower Performance and Settings

Provides performance data and adjustment guidelines for the furnace blower motor.

Furnace Operation and Maintenance

Integrated Control and Diagnostics

Explains the furnace control board, diagnostic codes, and operational sequences.

Unit Start-Up

Step-by-step guide for safely initiating furnace operation after installation.

Annual Furnace Maintenance

Outlines routine checks and tasks for maintaining the furnace system annually.