Lennox ML193UHE(K) Merit Series Gas Furnace

Product Specifications

AFUE: 93%

Input: 30,000 to 110,000 Btuh

Nominal Add-on Cooling: 3 to 5 Tons

Configuration: Upflow / Horizontal

Blower: High Efficiency Constant Torque Blower Motor

Refrigerant Detection: Ready

Cabinet Width: 17-1/2 in. or 21 in.

California Compliance: Meets California Nitrogen Oxides Standard (NOx) limits of 40 ng/J.

Model Number Identification

The model number provides details about the unit's configuration:

• Unit Type: ML = Merit® Series
• Stages: 1 = One-Stage
• AFUE: 93%
• Configuration: UH = Upflow/Horizontal
• Nominal Gas Heat Input: 030 (30,000 Btuh) to 110 (110,000 Btuh)
• Blower: E = High Efficiency Constant Torque Blower Motor
• California NOx Standard: X = Meets California Nitrogen Oxides Standard (40 ng/J)
• Cabinet Width: B (17-1/2 in.) or C (21 in.)
• Nominal Add-On Cooling Capacity: 36 (1.5-3 tons), 48 (2.5-4 tons), 60 (3-5 tons)

Feature Highlights

• Lennox Duralok Plus™ Heat Exchanger
• Secondary Heat Exchanger
• Inshot Burners
• Gas Control Valve
• Flame Rollout Switch
• Combustion Air Inducer
• SureLight® Integrated Furnace Control
• Power Saver™ Constant Torque Blower
• Insulated Cabinet
• Safety Interlock Switch
• Gas Piping And Electrical Inlets

Approvals and Warranty

• AHRI Certified
• Tested and rated according to US DOE test procedures and FTC labeling regulations
• ENERGY STAR® certified units are designed to use less energy.
• ISO 9001 Registered Manufacturing Quality System
• All models meet UL 60335-2-40 Refrigerant Detector Requirements.
• Warranty:
• Duralok Plus™ Aluminized Steel Heat Exchanger: Limited twenty years (residential), ten years (non-residential).
• All other components: Limited five years (residential), one year (non-residential).

Refer to Lennox® Basic Limited Warranty at www.lennox.com for additional details.

Features

Applications

• Input capacities: 30,000, 44,000, 66,000, 88,000, and 110,000 Btuh.
• Energy efficiency (AFUE): 93%.
• Compact cabinet for upflow, horizontal-left or horizontal-right applications without modifications.
• Lennox add-on indoor coils, high-efficiency air cleaners, and humidifiers can be easily added.
• Shipped factory assembled with all controls installed and wired.
• Factory test operated for proper operation.

Heating System

1. Lennox Duralok Plus™ Heat Exchanger Assembly: Consists of primary heat exchanger and secondary condenser coil assembly. Features a multi-pass crimped seam design. Constructed of heavy-gauge, aluminized steel for efficient expansion and contraction.
2. Secondary Heat Exchanger: Constructed of aluminum fins fitted to stainless steel tubes. Coil is factory tested for leaks. Features a condensate drain header box assembly.

Lennox Designed Header Box

Collects flue condensate for disposal through condensate drains. Drains are located on each side of the cabinet for easy field installation of a condensate drain trap. The condensate drain trap is included with the unit.

Inshot Burners

Aluminized steel burners provide efficient, trouble-free operation. Burner venturi mixes air and gas for proper combustion. Burner assembly is removable for service.

SureLight® Hot Surface Ignitor

Provides reliable, long-life performance. Ignitor is cemented to a steatite block for protection against current leakage. Ignition leads are constructed of nickel-plated copper with high-temperature Teflon® insulation.

Gas Control Valve

A 24-volt redundant combination gas control valve integrates manual shut-off, automatic electric valve, and gas pressure regulation.

Flame Rollout Switches (2)

Factory installed on the front of the burner box to provide protection from abnormal operating conditions. Manual reset required.

Limit Control

Primary limit is accurately located on the header box. Features automatic reset.

Combustion Air Inducer

A heavy-duty shaded pole blower prepurges the heat exchanger and safely vents flue products during the heating cycle. A pressure switch proves combustion air inducer operation before allowing the gas valve to open.

Controls

SureLight® Integrated Furnace Control

Contains all necessary controls and relays for furnace operation. Operates the combustion air inducer. Includes pre-purge (15 seconds) and post-purge (5 seconds) cycles. Features flame sensor for safe operation, with automatic re-attempts at ignition and lockout after flame loss. A diagnostic LED displays system status and error codes. Holds up to ten diagnostic codes. Includes adjustable blower timed-off delay and fixed blower timed-on delay. Terminals are provided for accessory power supply for humidifiers, air cleaners, and other 24V accessories. Ignition control has a single red LED for status indication. Supports twinning of two furnaces.

24 Volt Transformer (40VA)

Furnished and factory installed. Includes a circuit breaker.

Field Wiring Make-Up Box

Furnished for line voltage wiring. Factory installed internally on the left or right side of the furnace.

Refrigeration Detection System (RDS)

Complies with UL 60335-2-40 standard. Required for systems using R-454B refrigerant. Connects to the RDS Coil Sensor and acts as an interface between the indoor unit and thermostat. Ensures safe operation by stopping the compressor and/or heating and operating the blower to reduce refrigerant concentrations if R-454B is detected. Features a low GWP test button and an alarm/zone relay interface. Power is disabled to non-communicating thermostats if R-454B is detected. On system start-up, the blower runs for five minutes, and thermostat demands are disabled.

Optional Accessories

• 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 proper unit operation on installations above 4500 ft.
• Natural Gas to LPG/Propane Conversion Kit
• LPG/Propane to Natural Gas Conversion Kit
• Muffler (US Only): Reduces outdoor operating sound levels. Available in two-inch and three-inch diameters.
• M30 Smart Wi-Fi Thermostat: Wi-Fi-enabled, electronic, programmable touchscreen thermostat with 4 Heat/2 Cool, auto-changeover, dual-fuel control, and humidification/dehumidification control. Features a 4.3 in. color touchscreen, LCD display, Smooth Setback Recovery, compressor short-cycle protection, and Smart Away™™™ technology. Compatible with Amazon Alexa® and Google Assistant.
• Remote Outdoor Temperature Sensor: Used with the M30 Smart Thermostat to display outdoor temperature.
• 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 furnaces used with zoning or defrost thermostats and other 24V accessories requiring a higher VA rating. Replaces the standard 40VA transformer.
• Condensate Drain Heat Cable Kits: Self-limiting wattage heat cable prevents condensate drain from freezing in unconditioned areas. Available in 6 or 24 ft. lengths.
• Horizontal Suspension Kit: Provides suspension of the unit and indoor coil in horizontal applications. Allows complete service access.
• Crawl Space Vent Drain Kit: Allows venting through a crawl space for upflow and horizontal applications. Certified to ULC S636 standard in Canada.
• Return Air Base: For upflow applications, used with B and C width cabinets.
• High Performance Economizer (Commercial Applications Only): Designed for applications requiring outdoor air for free cooling.
• Air Filter and Rack Kit: Available for horizontal (end) and upflow side return air applications.
• Termination Kits: Various kits for direct vent, flush-mount, and wall-close couple applications.
• Flue Coupling: Assists with exhaust flue piping connection and servicing.

Specifications

Installation Clearances

NOTE: Air for combustion must conform to National Fuel Gas Code (NFPA 54/ANSI-Z223.1) or CAN/CSA-B149.1. Flue sizing must conform to National Fuel Gas Code or local building codes. Do not install the furnace directly on carpeting, tile, or other combustible materials other than wood flooring.

Gas Heat Accessories

NOTE: Two-inch diameter muffler (15Y66) is optional for 110 input model with a maximum vent pipe length of up to 29 ft. Three-inch diameter muffler (16A56) is optional for 110 input model with a minimum vent pipe length of 30 ft.

High Altitude Derate

Units may be installed at altitudes up to 10,000 ft. At altitudes above 4501 ft., the unit must be derated. Units installed at altitudes of 4501 to 10,000 ft. require a pressure switch change. Units installed at altitudes of 7501 to 10,000 ft. require an orifice change. Refer to the Gas Heat Accessories table for ordering information.

NOTE: In Canada, certification for installations at elevations over 4500 feet is the jurisdiction of local authorities.

Dimensions

Unit - Upflow Position

Diagrams and a table provide dimensional data for upflow installations.

Unit - Horizontal Position

Diagrams and a table provide dimensional data for horizontal installations, including left-hand and right-hand air discharge.

Optional Accessories - Filter Kits

Details on Horizontal (End) Filter Kit and Upflow Side Return Air Filter Kit are provided.

Optional Accessories - Venting

Information on Flush-Mount Vent Termination Kits, Concentric Wall and Roof Termination Kits, and Close-Couple Wall Termination Kits is available, including diagrams and specifications.

Mufflers

Specifications for 2-inch and 3-inch mufflers are provided.

Blower Data

Tables provide detailed blower performance data (Air Volume / Watts) at various external static pressures and blower speeds for different models, including less filter performance.