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Lennox ML296UHV(K) Merit Series Gas Furnace – Supplied & Professionally Installed by 4Most Energy
The Lennox® ML296UHV(K) Merit® Series is a 96% AFUE, two-stage, variable-speed condensing gas furnace engineered for upflow, horizontal-left, or horizontal-right installation without cabinet modification, with four input sizes from 44,000 to 110,000 Btuh covering 2 to 5 nominal tons of add-on cooling. The Duralok Plus™ primary and secondary heat exchanger, SureLight® hot surface ignition, two-stage gas control valve, and ECM variable-speed blower deliver ENERGY STAR-qualified performance, while the factory-installed Refrigerant Detection System readies the (K) models for R-454B-charged outdoor equipment under UL 60335-2-40.
Equipment specifications alone do not determine how this furnace performs once it is running in an Ontario home. Sealed-combustion direct-vent or non-direct-vent operation must be piped to the manufacturer's maximum vent lengths for 2, 2-1/2, or 3-inch PVC, PolyPro, or InnoFlue pipe at the installed elevation and winter design temperature; gas line and meter capacity must be sized to the selected input by a licensed TSSA gas technician; and combustion testing, manifold pressure verification, and temperature-rise confirmation are required at start-up under CAN/CSA-B149.1 and the Ontario Building Code. Coil match-up using same-letter cased coils, or an adaptor base for uncased coils, condensate trap routing, and correct 120V electrical hookup to the integrated furnace control are the remaining code-driven steps that separate a rated 96% AFUE furnace from one that actually delivers it.
4Most Energy supplies and installs the ML296UHV(K) as a certified gas furnace installation Toronto and gas furnace replacement GTA contractor, providing Lennox ML296UHV installation Ontario service with licensed gas technician near me-level combustion testing on every job, and sizing every install to qualify as an ENERGY STAR gas furnace Toronto upgrade wherever the home's ductwork and gas supply support it.
Warranty
Lennox backs the ML296UHV(K) Duralok Plus™ aluminized steel heat exchanger with a 20-year limited warranty in residential applications (10-year limited in non-residential applications). All other covered components carry a 5-year limited warranty in residential applications (1-year limited in non-residential applications). 4Most Energy completes and files start-up documentation to keep coverage valid.
The 4Most
Furnace Replacement
Process
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We take the stress out of home heating upgrades with a streamlined, professional process designed for longevity and performance.
Why Install the Lennox ML296UHV(K) with 4Most Energy?
- 96% AFUE efficiency — two-stage heating with a variable-speed ECM blower for high fuel efficiency and quiet, consistent comfort, meeting ENERGY STAR® certification requirements.
- Lennox Duralok Plus™ heat exchanger — primary heat exchanger and secondary condensing coil assembly of heavy-gauge, multi-pass crimped-seam aluminized steel, factory leak-tested and designed for normal expansion and contraction with minimal airflow resistance.
- SureLight® hot surface ignitor — silicon nitride ignitor cemented to a steatite block for protection against current leakage, with nickel-plated copper ignition leads in high-temperature Teflon® insulation for reliable, trouble-free starts.
- Two-stage gas control valve — 24-volt redundant combination valve combining manual shutoff, dual automatic electric valves, and gas pressure regulation in a single compact control.
- Two-speed combustion air inducer — heavy-duty PSC motor pre-purges the heat exchanger and safely vents flue products; dual pressure switches confirm low-fire and high-fire blower operation before the gas valve is allowed to open.
- SureLight® integrated two-stage/variable-speed furnace control — Auto Configuration communicates unit setup to an optional Lennox® Communicating Thermostat, Innovative AirFlex™ technology allows custom blower settings by application, and a seven-segment diagnostic LED holds up to 10 fault codes for fast service.
- Variable-speed direct-drive blower — ECM motor ramps smoothly up and down at the start and end of each cycle, supports adjustable continuous-fan operation, and is compatible with Lennox® LZSV variable zoning systems (minimum 300–460 cfm depending on model).
- Refrigerant Detection System (RDS) — part of the SureLight Integrated Furnace Control on (K) models; complies with UL 60335-2-40 and supports up to two RDS coil sensors, automatically disabling compressor/heating operation and running the blower to clear the space if R-454B refrigerant is detected.
Lennox ML296UH Specifications
| Model | ML296UH045XV36BK | ML296UH070XV36BK | ML296UH090XV48CK | ML296UH110XV60CK |
|---|---|---|---|---|
| AFUE | 96% | 96% | 96% | 96% |
| High Fire Input (Btuh) | 44,000 | 66,000 | 88,000 | 110,000 |
| High Fire Output (Btuh) | 42,000 | 62,000 | 85,000 | 106,000 |
| Low Fire Input (Btuh) | 29,000 | 43,000 | 57,000 | 72,000 |
| Low Fire Output (Btuh) | 28,000 | 41,000 | 55,000 | 70,000 |
| High Fire Temp Rise (°F) | 35–65 | 50–80 | 45–75 | 45–75 |
| Nominal Add-On Cooling | 2–3 tons | 2–3 tons | 2.5–4 tons | 3–5 tons |
| Cabinet Width | 17-1/2 in. ("B") | 17-1/2 in. ("B") | 21 in. ("C") | 21 in. ("C") |
| Air Volume Range (cfm) | 485–1,370 | 500–1,365 | 680–1,770 | 790–1,955 |
| Intake/Exhaust Pipe | 2 in. PVC | 2 in. PVC | 2 in. PVC | 2 in. PVC |
| Gas Pipe Size (IPS) | 1/2 in. | 1/2 in. | 1/2 in. | 1/2 in. |
| Blower Motor Full Load Amps | 7.7 A | 7.7 A | 9.6 A | 12.8 A |
| Max. Overcurrent Protection | 15 A | 15 A | 15 A | 20 A |
| Shipping Weight | 130 lb | 138 lb | 163 lb | 174 lb |
Electrical service for all models: 120 volts, 60 Hz, 1 phase. High static pressure rating: 0.8 in. w.g. heating / 1.0 in. w.g. cooling for all models. Gas manifold pressure (high fire/low fire, natural gas): 3.5 / 1.7 in. w.g.; (LPG/propane): 10.0 / 4.5 in. w.g. Filters and provisions for mounting are not furnished and must be field provided.
Furnace input (Btuh) should be selected from a proper Manual J or equivalent heat-loss calculation for the home, using Ontario winter design temperatures rather than by matching the size of the equipment being replaced — many existing furnaces were oversized from the outset.
The ML296UHV(K) line ships in two cabinet widths: the 17-1/2 in. "B" cabinet (045 and 070 models, 2–3 tons of add-on cooling) and the 21 in. "C" cabinet (090 and 110 models, 2.5–5 tons of add-on cooling), so cooling tonnage and any existing indoor coil should be checked against the correct cabinet width before ordering.
Lennox add-on cooling coils must share the same letter designation (A, B, C, or D) as the furnace for a no-adaptor fit; an uncased coil requires an adaptor base or field-fabricated transition.
On the 110 model, air volumes over 1,800 cfm (shown in bold in the blower tables) require single-side return air with the optional return air base, bottom return air, return air from both sides, or bottom-and-one-side return — a detail that affects ductwork planning before installation day.
Furnace Installation Workflow
| Phase | Primary Tasks & Key Requirements |
|---|---|
| Site Assessment | Existing equipment inspection, gas line and meter capacity check, electrical service verification, and confirmation of installation orientation (upflow, horizontal-left, or horizontal-right). |
| Load Calculation & Sizing | Confirm correct Btuh input, cabinet width, and add-on cooling coil compatibility for the home. |
| Venting Design | Select 2, 2-1/2, or 3-inch PVC, PolyPro, or InnoFlue vent pipe and termination kit sized to the unit's maximum vent length at the installed elevation and Ontario winter design temperature. |
| Placement & Connections | Set the furnace in the confirmed orientation, connect supply/return ductwork and coil, and route the condensate trap and drain per the installation instructions. |
| Gas Line & Venting Connection | A licensed TSSA gas technician sizes and connects the gas line for the selected input, installs the intake/exhaust vent piping and termination, and verifies supply pressure. |
| Electrical Connection | 120V hookup to the integrated SureLight furnace control, with DIP switch configuration for thermostat type, blower speed, and (where applicable) Refrigerant Detection System settings. |
| Commissioning | Combustion analysis, gas manifold pressure verification, temperature-rise confirmation against the rating plate range, and blower speed tap adjustment for the home's ductwork. |
| Final Walkthrough | Filter access, service clearances, thermostat setup, and diagnostic LED location reviewed with the homeowner before the crew leaves site. |
Lennox covers the Duralok Plus™ aluminized steel heat exchanger for 20 years, limited, in residential installations (10 years limited in non-residential installations), and covers all other components for 5 years, limited, in residential installations (1 year limited in non-residential installations). 4Most Energy completes and files the required start-up and combustion-test documentation with every install to keep coverage valid.
Routine maintenance keeps the ML296UHV(K) running at its rated efficiency: annual combustion analysis and gas-train inspection, inshot burner and hot surface ignitor cleaning, condensate trap and drain servicing, flue and intake pipe inspection for blockage or deterioration, and regular filter replacement (filters are field-supplied and not furnished with the unit). 4Most Energy recommends an annual pre-season tune-up to confirm gas pressure, temperature rise, and blower operation remain within the factory-specified ranges shown on the unit rating plate.
Service Area
Greater Toronto Area (GTA) and surrounding regions
Toronto, Markham, Richmond Hill, Vaughan, Aurora, Newmarket, Scarborough, Brampton, and Mississauga.
Extended Service Area: Stouffville, Oshawa, Barrie, Orangeville, Hamilton, St. Catharines, Guelph, Kitchener.
Frequently Asked Questions
What's the difference between the "B" cabinet (045/070) and "C" cabinet (090/110) models?
The 17-1/2 in. "B" cabinet models support 2–3 tons of nominal add-on cooling, while the 21 in. "C" cabinet models support 2.5–5 tons. Cabinet width also determines which Lennox cased coils will fit without an adaptor, so the correct model depends on both heating load and planned or existing cooling capacity.
Can this furnace be installed horizontally in an attic or crawl space?
Yes. The same cabinet installs upflow, horizontal-left, or horizontal-right without modification, though horizontal installations require a horizontal suspension kit and the flue condensate trap assembly mounted below the cabinet rather than beside it.
What does the "(K)" in ML296UHV(K) mean?
The (K) suffix indicates Refrigerant Detection-Ready models, which include a factory-installed Refrigerant Detection System (RDS) as part of the SureLight Integrated Furnace Control, required for systems using R-454B refrigerant under UL 60335-2-40.
Does the ML296UHV(K) qualify for Ontario or federal energy rebates?
At 96% AFUE, this furnace exceeds the efficiency threshold commonly required by Canada Greener Homes Grant and utility rebate programs for high-efficiency gas furnaces, though
Can I pair this furnace with my existing central air conditioner?
In most cases, yes, provided the outdoor unit's tonnage falls within the furnace's rated add-on cooling range and the existing indoor coil is AHRI-matched or compatible via an adaptor. 4Most Energy confirms compatibility during the site assessment before quoting.
