Lennox ML196UHE(K) Gas Furnaces

The furnace is available in input capacities of 30,000, 44,000, 66,000, 88,000, 110,000, and 135,000 Btuh. It offers 96% AFUE and a compact cabinet suitable for upflow, horizontal-left, or horizontal-right applications without modification. Lennox add-on indoor coils, air cleaners, and humidifiers can be easily integrated. Units are shipped factory-assembled with all controls installed and wired, and are factory test-operated.

Lennox Duralok Plus™ Heat Exchanger Assembly: Features a primary heat exchanger and a secondary condenser coil assembly. It uses a multi-pass crimped seam design, constructed from heavy-gauge, aluminized steel for expansion and contraction with maximum efficiency and minimum airflow resistance.

Secondary Heat Exchanger: Constructed with aluminum fins on stainless steel tubes, factory tested for leaks. Includes a condensate drain header box assembly on the front of the coil, designed for easy field installation of condensate drains. The compact design contributes to the overall furnace cabinet size and has undergone laboratory life cycle testing.

Lennox Designed Header Box: Collects flue condensate for disposal through condensate drains, with drains located on both sides of the cabinet. A condensate drain trap is included.

Inshot Burners: Provide efficient, trouble-free operation by mixing air and gas for proper combustion. The burner assembly is removable as a single component for service.

SureLight® Hot Surface Ignitor: Offers tough, reliable, long-life performance using a silicon nitride ignitor cemented to a steatite block. Ignition leads are nickel-plated copper enclosed in high-temperature Teflon® insulation.

Gas Control Valve: A 24-volt redundant combination control integrating manual shut-off, automatic electric valve (dual), and gas pressure regulation.

Combustion Air Inducer: A shaded pole, heavy-duty blower that purges the heat exchanger and safely vents flue products during the heating cycle.

Pressure Switch: Ensures proper Combustion Air Inducer operation before allowing the gas valve to open.

Limit Control: Primary limit is located on the header box with automatic reset.

Flame Rollout Switches (2): Factory installed on the front of the burner box for protection against abnormal conditions, featuring manual reset.

Lennox Designed Flue Condensate Trap Assembly: Field installed outside the conditioned air stream, mountable on either side of the cabinet in upflow applications or below the cabinet in horizontal applications. Can also be mounted remotely (up to 5 ft.). Includes a 90° street elbow for drain trap installation. Drain connections can be made with field-provided PVC pipe or coupling. A drain cap allows for easy cleaning and winterizing.

High Altitude Orifice Kits: Required for proper operation at altitudes from 7501 to 10,000 ft. Available for natural gas and LPG/propane.

High Altitude Pressure Switch Kit: Required for installations above 4500 ft.

Natural Gas to LPG/Propane Conversion Kit: For field changeover.

LPG/Propane to Natural Gas Conversion Kit: For field changeover.

Muffler (US Only): Reduces outdoor operating sound levels. Available in 2-inch and 3-inch diameters for specific input models and vent pipe lengths.

Direct Vent / Non-Direct Vent Sealed Combustion System: Features a sealed combustion system for Direct Vent (outdoor air intake, outdoor exhaust) or Non-Direct Vent (indoor air intake, outdoor exhaust) applications. Lennox approves DuraVent® PolyPro® and Centrotherm InnoFlue® as alternatives to PVC vent pipe.

SureLight® Integrated Furnace Control: Manages all furnace operations, including pre-purge (15 seconds) and post-purge (5 seconds) cycles for the combustion air inducer. Features flame sensing for safety, multiple ignition re-attempts before lockout, and a watchguard circuit for automatic reset. Includes a seven-segment LED display for diagnostics and system status, with up to ten diagnostic codes stored in non-volatile memory. Offers adjustable blower timed-off delay (60-180 seconds) and fixed blower timed-on delay. Provides terminals for 120V (1 amp max) and 24V (0.5 amp max) accessories. Includes a single red LED for ignition status. Twinning terminals are provided for connecting two furnaces.

24 Volt Transformer (40VA): Furnished and factory installed.

Field Wiring Make-Up Box: Provided for line voltage wiring, factory installed internally.

Part of the SureLight® Integrated Furnace Control, compliant with UL 60335-2-40. Required for systems using R-454B refrigerant. It interfaces with the indoor unit and thermostat to ensure safe operation. If R-454B refrigerant is detected, the system stops the compressor and/or heating and operates the blower to reduce concentrations. Resumes normal operation when safe levels are reached. Includes a Low GWP test button. An Alarm/Zone relay interface can trigger external alarms or open zone dampers. Power is disabled to non-communicating thermostats. On system start-up, the blower runs for five minutes with thermostat demands disabled.

M30 Smart Wi-Fi Thermostat: Wi-Fi enabled, 7-day, multi-stage, programmable, touchscreen thermostat with 4 Heat/2 Cool settings. Supports auto-changeover and dual-fuel control. Offers enhanced capabilities like humidification/dehumidification control (Humiditrol®), equipment maintenance reminders, a 4.3-inch color touchscreen, and smooth setback recovery. Features compressor short-cycle protection and up to four schedules. Smart Away™ technology uses geo-fencing for automated system operation. Compatible with Amazon Alexa® and Google Assistant. Online real-time monitoring is available via a Service Dashboard.

Remote Outdoor Temperature Sensor: Used with the M30 Smart Thermostat to display outdoor temperature, required for Enhanced Dehumidification Accessory (EDA).

Blower Relay Kit: For two-stage outdoor units, allows furnace blower speed changes when matched with two-stage air conditioners or heat pumps.

Transformer (75VA): Recommended for zoning or dual-fuel systems requiring higher VA rating, replaces the standard 40VA transformer.

The cabinet is low-profile and narrow for easy installation, constructed of heavy-gauge, cold-rolled steel with a pre-painted finish. Supply air opening flanges facilitate plenum connection. The heating compartment is insulated with foil-faced insulation. The blower compartment is sealed for complete service access. A safety interlock switch automatically shuts off power when the blower compartment door is removed. Gas piping and electrical inlets are provided on both sides.

Low Leakage Cabinet: Features less than 2% air leakage, meeting ANSI/ASHRAE Standard 193-2010.

Bottom/Side Return Air Entry: Configurable for upflow/horizontal with bottom return, or upflow with side return. Specific notes apply for units requiring over 1800 cfm, potentially needing an Optional Return Air Base for proper filter fitment.

Coil Match-Up: Furnaces are designed to match Lennox cased upflow and horizontal indoor coils with the same letter designation (A, B, C, D) in the model number, requiring no adapter.

Optional Accessories (Cabinet):

• Condensate Drain Heat Cable Kits: Self-limiting wattage heat cable to prevent condensate drain freezing in unconditioned areas. Available in 6 or 24 ft. lengths.
• Horizontal Suspension Kit: For suspending the unit and indoor coil in horizontal applications, including brackets with vibration isolators.
• Crawl Space Vent Drain Kit: For venting through crawl spaces, includes PVC components and is certified to ULC S636 for Canada.
• Return Air Base: For upflow applications with B, C, and D cabinets, ensuring proper fitment for IAQ cabinets and return air openings.
• High Performance Economizer: For commercial applications, utilizing outdoor air for free cooling.

Filter and provisions for external mounting must be field provided. Optional Air Filter and Rack Kits are available for horizontal (end) and upflow (side) return air applications.

Units may be installed up to 10,000 ft. At altitudes above 4501 ft., derating is required. Units at 4501-10,000 ft. need a pressure switch change. Units at 7501-10,000 ft. need an orifice change. Refer to the Gas Heat Accessories table for ordering information. In Canada, elevation certification is a local authority jurisdiction.

Note: Air for combustion must conform to National Fuel Gas Code (NFPA 54/ANSI-Z223.1) or National Standard of Canada CAN/CSA-B149.1. Flue sizing must conform to current codes. Allow proper clearances for condensate trap and vent pipe installation. Do not install directly on carpeting, tile, or other combustible materials other than wood flooring.

Tables provide maximum equivalent vent lengths for various termination types (Standard, Concentric, Flush-Mount, Wall Close-Couple) and conditions (elevation, pipe size, intake air source). These tables are crucial for ensuring proper venting and performance.

Note: Additional vent pipe and long radius elbows required for termination must be included in total vent length calculations. Intake and exhaust pipes are sized separately.

Dimensional drawings and tables are provided for both Upflow and Horizontal unit positions, as well as for optional accessories like filter kits and termination kits.

Comprehensive blower performance data is presented in tables, detailing Air Volume (cfm) and Watts consumed at various External Static Pressures and Blower Speeds (High, Medium-High, Medium, Medium-Low, Low) for each model. This data is essential for system design and performance analysis.

Visit Lennox at www.Lennox.com for the latest technical information and www.LennoxPros.com for professional resources. Contact Lennox customer service at 1-800-9-LENNOX.

Note: Lennox reserves the right to change specifications, ratings, and dimensions without notice. Improper installation, adjustment, alteration, service, or maintenance can cause property damage or personal injury. Installation and service must be performed by a qualified installer and servicing agency. ©2025 Lennox Industries, Inc.