Lennox ML196UH090XE48C

Page 1
INSTALLATION
INSTRUCTIONS
ML196UHE
507966-04
04/2021
Supersedes 507966-03
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.
© 2021 Lennox Industries Inc.
Dallas, Texas USA
MERIT
®
SERIES GAS FURNACE
UPFLOW / HORIZONTAL AIR DISCHARGE
Contents
Unit Dimensions - inches (mm) ......................................2
ML196UHE .....................................................................3
Shipping and Packing List ..............................................3
Safety .............................................................................3
Use of Furnace as a Construction Heaterl .....................4
General ...........................................................................5
Combustion, Dilution, Ventilation Air...............................5
Setting Equipment ..........................................................8
Filters ............................................................................13
Duct System .................................................................13
Pipe Fittings Specications...........................................13
Joint Cementing Procedure .......................................... 16
Venting Practices ..........................................................16
Gas Piping ....................................................................36
Electrical .......................................................................39
Unit Start-Up .................................................................42
Gas Pressure Measurement.........................................44
Proper Combustion.......................................................44
High Altitude .................................................................44
Testing Combustion Air For Non-Dierct Vent ................ 46
Other Unit Adjustments.................................................46
Service..........................................................................48
Repair Parts List ...........................................................49
Start-Up Checklist.........................................................51
Blower Data ..................................................................53

Lennox ML196UH090XE48C Specifications

General

Brand	Lennox
Model	ML196UH090XE48C
Category	Furnace
Type	Gas
Efficiency Rating	96% AFUE
Input BTU	90, 000
Blower Motor	Variable Speed
Stages	Two-Stage
Ignition Type	Hot Surface Ignition
Heat Exchanger Warranty	Limited Lifetime
Output BTU	86, 400 BTU/h
Unit Warranty	10-year Limited Warranty

Summary

Safety Information

General Safety Precautions

Provides critical warnings and cautions for installation and handling of the furnace.

Installation Locations

Permitted Installation Sites

Details acceptable locations for furnace installation, including garages and attics.

Combustion, Dilution & Ventilation Air

Air Requirements for Non-Direct Vent

Details air supply needs for non-direct vent installations to ensure safe operation.

Confined Space Air Requirements

Specifies air intake requirements for furnaces installed in confined spaces.

Installation - Setting Equipment

Upflow Application Setup

Provides instructions for setting up the furnace for upflow installation, including leveling.

Installation Clearances

Clearance Requirements Table

Specifies minimum clearances to combustible materials for safe installation.

Return Air Guidelines

Return Air Intake Configurations

Venting Practices

Vent Piping Guidelines

General Guidelines for Vent Terminations

Venting Codes and Clearances

VENT TERMINATION CLEARANCES FOR NON-DIRECT VENT INSTALLATIONS

US vs. Canadian Clearances

Specifies required clearances for vent terminals in the US and Canada for non-direct vent systems.

VENT TERMINATION CLEARANCES FOR DIRECT VENT INSTALLATIONS

US vs. Canadian Clearances for Direct Vent

Specifies required clearances for vent terminals in the US and Canada for direct vent systems.

Intake and Exhaust Piping Details (Direct Vent)

Direct Vent Termination Configurations

Exhaust Piping Terminations (Non-Direct Vent)

Non-Direct Vent Termination Guidelines

Gas Piping

Gas Supply Connection

Covers the installation requirements and safety precautions for connecting the gas supply.

Leak Detection Procedure

Electrical

Electrical Precautions and Grounding

Details electrical safety, wiring requirements, and grounding for the furnace.

Unit Start-Up

Safety Before Operation

Provides essential safety checks and warnings before operating the furnace for the first time.

Gas Flow Measurement

Proper Combustion

Combustion Analysis

Guides on how to check and ensure proper combustion by measuring CO2 and CO levels.

Testing for Proper Venting and Sufficient Combustion Air for Non-Direct Vent Applications

Non-Direct Vent Testing Procedure

Unit Adjustments and Settings

Pressure Switch and Temperature Rise

Service and Maintenance

Annual Furnace Maintenance