Lennox ML296UHV Gas Furnace
Residential Product Specifications
Overview
The Lennox ML296UHV is a Merit® Series gas furnace designed for Upflow or Horizontal installation. It features two-stage heating and a variable speed blower, offering an AFUE of 96%. The furnace is available with input capacities ranging from 44,000 to 110,000 Btuh and is suitable for nominal add-on cooling capacities from 3 to 5 tons.
Model Number Identification: The model number provides key information about the unit:
- Unit Type: ML = Merit® Series
- Stages: 2 = Two-Stage
- AFUE: 96 = 96%
- Configuration: UH = Upflow/Horizontal
- Nominal Gas Heat Input: 045 (44,000 Btuh), 070 (66,000 Btuh), 090 (88,000 Btuh), 110 (110,000 Btuh)
- Cabinet Width: B = 17-1/2 in., C = 21 in.
- Nominal Add-On Cooling Capacity: 36 = 3 tons, 48 = 4 tons, 60 = 5 tons
- Blower: V = Variable Speed Blower Motor
- Low NOx: X = Meets California Nitrogen Oxides Standard (40 ng/J)
Feature Highlights
The ML296UHV furnace incorporates several advanced features for efficient and reliable operation:
- Lennox Duralok Plus™ Heat Exchanger
- Secondary Heat Exchanger
- Inshot Burners
- SureLight® Hot Surface Ignitor
- Two-Stage Gas Control Valve
- Two-Speed Combustion Air Inducer
- Flame Rollout Switches
- SureLight® Integrated Furnace Control
- Variable Speed Direct Drive Blower
- Insulated Cabinet
- Safety Interlock Switch
- Gas Piping And Electrical Inlets
Note: ML296UHV furnaces cannot be twinned.
Approvals and Warranty
The furnace is AHRI Certified and CSA International Certified, tested and rated according to US DOE test procedures and FTC labeling regulations. It is approved by the California Energy Commission and meets California Nitrogen Oxides Standard (NOx) limits of 40 ng/J. It is also ENERGY STAR® certified.
Warranty:
- Duralok Plus™ Aluminized Steel Heat Exchanger: Limited twenty years (residential), ten years (non-residential).
- All other covered components: Limited five years (residential), one year (non-residential).
California Specific: These furnaces do not meet the South Coast Air Quality Management District (SCAQMD) Rule 1111 and San Joaquin Valley Air Pollution Control District (SJVAPCD) Rule 4905 NOx emission limit (14 ng/J) and cannot be installed within those specific areas. However, they are approved by the California Energy Commission and meet the NOx limits of 40 ng/J.
Applications
- Input capacities: 44,000, 66,000, 88,000, and 110,000 Btuh.
- Energy efficiency (AFUE): 96%.
- Compact cabinet design allows for upflow, horizontal-left, or horizontal-right installations without modifications.
- Variable speed blower is ideal for zoning applications.
- Removable bottom seal panel facilitates side return air or bottom/end return air configurations.
- Suitable for installation in utility rooms, alcoves, closets, crawl spaces, or attics.
- Compatible with Lennox add-on indoor coils, high-efficiency air cleaners, and humidifiers.
- Shipped factory assembled with all controls installed and wired.
- Each unit is factory test operated for proper operation.
Zoning Applications
The ML296UHV can be used with certain zoning systems. The zone control panel must be able to interface and communicate with the variable speed blower motor. The Harmony III™ Zoning System is compatible.
Heating System Details
- Lennox Duralok Plus™ Heat Exchanger Assembly: Features a primary heat exchanger and a secondary condenser coil assembly. It is a multi-pass, crimped seam design constructed of heavy-gauge, aluminized steel for efficient operation and durability.
- Secondary Heat Exchanger: Consists of aluminum fins fitted to stainless steel tubes, factory tested for leaks. The condensate drain header box is located on the front of the coil.
Lennox Designed Header Box
Collects flue condensate for disposal through condensate drains located on the sides of the cabinet. A condensate drain trap is included for field installation.
Lennox Designed Flue Condensate Trap Assembly
This assembly is field installed outside the conditioned air stream and can be mounted on either side of the cabinet or remotely.
Burners
Aluminized steel inshot burners provide efficient, trouble-free operation. The burner venturi mixes air and gas for proper combustion. The burner assembly is removable for service.
SureLight® Hot Surface Ignitor
A reliable, long-life ignitor made of silicon nitride, cemented to a steatite block for protection. Ignition leads are nickel-plated copper with high-temperature Teflon® insulation.
Two-Stage Gas Control Valve
A 24-volt redundant combination valve that includes manual shut-off, automatic electric valve, and gas pressure regulation.
Two-Speed Combustion Air Inducer
Features a permanent split capacitor (PSC) motor. It purges the heat exchanger and safely vents flue products. Dual pressure switches ensure proper blower operation before gas valve opening. Operates only during the heating cycle.
Flame Rollout Switches (2)
Factory installed on the burner box to protect against abnormal operating conditions. Features manual reset.
Limit Control
Primary limit is accurately located on the vestibule panel. Features automatic reset.
Optional Accessories
- High Altitude Orifice Kits: Required for 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
- LPG/Propane to Natural Gas Conversion Kit
- Muffler (US Only): Reduces outdoor operating sound levels. Available for 070 through 110 input models.
- iComfort® M30 Smart Wi-Fi Thermostat: Wi-Fi enabled, programmable thermostat with a 4.3-inch color touchscreen, offering advanced control of humidity, dewpoint, and equipment maintenance reminders.
- Remote Outdoor Temperature Sensor: Used with the iComfort® M30 for displaying outdoor temperature.
- Filter Kits: Available for horizontal (end) and upflow side return applications.
- Termination Kits: Various kits for direct vent (concentric, flush-mount, wall close-couple) and roof termination applications.
- Venting Accessories: Flue coupling, roof termination flashing kits.
Blower Data
The ML296UHV features a variable speed direct drive blower. The blower performance tables provide detailed information on airflow (cfm) at various static pressures for heating and cooling modes, across different jumper settings.
Cabinet
The cabinet is low-profile and narrow, constructed of heavy-gauge, cold-rolled steel with a pre-painted finish. It includes flanges for easy plenum connection and is insulated with foil-faced insulation. The blower compartment is sealed, and the cabinet door can be removed for service access. A safety interlock switch prevents operation when the door is removed.
Return Air Entry
The furnace supports upflow/horizontal applications with bottom or side return air. Specific configurations and requirements for units needing over 1800 cfm are detailed, including the use of an Optional Return Air Base.
Installation Clearances
Specific minimum clearances are provided for sides, rear, top/plenum, front, front (service/alcove), and floor installations. Combustible clearances are also noted.
Ventilation
Detailed tables provide vent lengths for various termination types (standard, concentric) at different elevations (0-4500 ft. and 4501-10,000 ft.) and pipe diameters. Notes on vent pipe materials (PVC, PolyPro®, InnoFlue®) and elbow equivalencies are included.
Specifications Summary
| Model No. | Heating Performance (AFUE) | High Fire Input (Btuh) | Low Fire Input (Btuh) | Connections (Intake/Exhaust Pipe Size) | Indoor Blower (Wheel Dia. x Width) | Electrical Data (Voltage) | Shipping Data (lbs.) |
|---|---|---|---|---|---|---|---|
| ML296UH045XV36B | 96% | 44,000 | 29,000 | 2/2 in. | 10 x 9 in. | 120 volts | 130 |
| ML296UH070XV36B | 96% | 66,000 | 43,000 | 2/2 in. | 10 x 9 in. | 120 volts | 138 |
| ML296UH090XV48C | 96% | 88,000 | 57,000 | 2/2 in. | 11 x 11 in. | 120 volts | 163 |
| ML296UH110XV60C | 96% | 110,000 | 72,000 | 2/2 in. | 11 x 11 in. | 120 volts | 174 |
