Lennox International Inc Merit Series Gas Furnace Planned Service, Repair Parts List

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Planned Service

The following items should be checked during an annual inspection. Power to the unit must be shut off for the service techni- cian’s safety.

Fresh air grilles and louvers (on the unit and in the room where the furnace is installed) − Must be open and unob- structed to provide combustion air.

Burners − Must be inspected for rust, dirt, or signs of water.

Vent pipe − Must be inspected for signs of water, damaged or sagging pipe, or disconnected joints.

Unit appearance − Must be inspected for rust, dirt, signs of water, burnt or damaged wires, or components.

Blower access panel − Must be properly in place and pro- vide a seal between the return air and the room where the furnace is installed.

Return air duct − Must be properly attached and provide an air seal to the unit.

Operating performance − Unit must be observed during operation to monitor proper performance of the unit and the vent system.

Combustion gases − Flue products must be analyzed and compared to the unit specifications.

Problems detected during the inspection may make it nec- essary to temporarily shut down the furnace until the items can be repaired or replaced.

Instruct the homeowners to pay attention to their furnace. Situations can arise between annual furnace in- spections that may result in unsafe operation. For instance, items innocently stored next to the furnace may obstruct the combustion air supply. This could cause incomplete combustion and the production of carbon monoxide gas.

Repair Parts List

The following repair parts are available through independent Lennox dealers. When ordering parts, include the complete furnace model number listed on the CSA International nameplate −− Example: ML180UH045P24A−01. All service must be performed by a licensed professional installer (or equivalent), service agency, or gas supplier.

Cabinet Parts

Upper access panel

Blower panel

Top cap

Control Panel Parts

Transformer Integrated control Door interlock switch Circuit breaker

Blower Parts Blower wheel Blower housing Motor

Motor mounting frame Motor capacitor

Blower housing cutoff plate

Heating Parts

Flame sensor

Heat exchanger assembly Gas manifold Combustion air inducer Gas valve

Main burner cluster Main burner orifices Pressure switch Ignitor

Primary limit control Flame rollout switch (s) Secondary limit

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Contents Installation Instructions ML180UH Table of ContentsUnit Dimensions − inches mm TOP ViewParts Arrangement Shipping and Packing List Safety InformationML180UH Gas Furnace Use of Furnace as Construction Heater GeneralCombustion, Dilution & Ventilation Air Equipment in Confined Space ALL AIR from Inside Equipment in Confined Space Setting Equipment Return Air Plenum End Bottom Horizontal Application Installation Clearances Top LeftRight Filters Duct SystemTop Vent Discharge VentingUpflow Position Left Side Vent DischargeSide Vent Discharge Horizontal Left PositionHorizontal Right Position Vent Connection Upflow and Horizontal Position Common Venting Using Metal−Lined Masonry Chimney −1/2 Cated or common venting system, you must inspect 18 − The common vent diameter must always be at least asFeet FAN + FAN FAN + NAT 112 175 169 278 Carbon Monoxide Poisoning Hazard Gas Piping Ers or straps. Install a drip leg in vertical pipe runs to− In some localities, codes may require the installation Every 8 to 10 feet 2.44 to 3.01 m with suitable hangRight−Side Air Discharge Horizontal ApplicationLeft−Side Air Discharge Electrostatic Discharge ESD Interior MAKE−UP BOX InstallationElectrical Thermostat Designations ML180UH Schematic Wiring Diagram and Sequence of Operation Typical ML180UH Field Wiring Diagram Integrated ControlFor Your Safety Read Before Lighting Unit Start−UpHigh Altitude Gas Pressure AdjustmentProper Combustion Other Unit Adjustments Manifold Pressure Settings at all AltitudesHeat FAN-OFF Time in Seconds No Jumper680 453 900750 885860 Single Side Return Air − Air volumes in bold require field1391 653Service Electrical SHOCK, Fire Or Explosion Hazard−090, −110 −135 units ML180UH BURNER, Combustion AIR Inducer AssemblyHeat Exchanger Removal −045 and −070 unitsPage Planned Service Repair Parts ListIntegrated Control Diagnostic Codes DescriptionTroubleshooting Heating Sequence of Operation Normal Heating Mode Abnormal Heating ModeHeating Sequence Troubleshooting Cooling Sequence of Operation Normal Cooling Mode Abnormal Cooling ModeTroubleshooting Continuous Fan Sequence of Operation Continuous Heat Speed FAN Sequence of Operation

Merit Series Gas Furnace specifications

Lennox International Inc. is a leading name in the heating and cooling industry, and their Merit Series Gas Furnace embodies the commitment to quality and efficiency that the company is known for. The Merit Series is designed to provide reliable heating in a sustainable manner, making it an excellent choice for homeowners seeking comfort without excessive energy bills.

One of the standout features of the Merit Series Gas Furnace is its efficiency ratings. The units in this series typically boast Annual Fuel Utilization Efficiency (AFUE) ratings of up to 95%. This level of efficiency means that the furnace converts a significant portion of the fuel it uses into heat, ultimately lowering operating costs. Such energy-efficient performance is not only beneficial for the wallet but also promotes environmental sustainability.

The Merit Series also incorporates advanced technologies that enhance its operation. The inclusion of a multi-speed blower motor is a notable feature that provides thoughtful airflow management throughout the home. By adjusting the speed according to the heating needs, the furnace optimizes comfort levels while minimizing noise and energy consumption. Homeowners can enjoy a warm environment without the disruptive sounds often associated with traditional furnaces.

Moreover, the Merit Series comes equipped with durable construction materials designed to withstand the test of time. From the robust heat exchanger to the heavy-gauge cabinet, Lennox focuses on longevity and reliability. This ensures that homeowners can trust their furnace to operate effectively even in the harshest winter conditions.

Safety features are also integral to the design of the Merit Series Gas Furnace. With an integrated Flame Sensor and a built-in safety shut-off system, the furnace ensures that any irregularities in operation are promptly detected and addressed. Such measures provide peace of mind for families using the heating system throughout the cold months.

Installation and maintenance are further simplified with the Merit Series. Its design facilitates easier access for HVAC professionals, allowing for quicker installations and routine service, ensuring that homeowners spend less time and money on upkeep.

In conclusion, Lennox International Inc.'s Merit Series Gas Furnace combines efficiency, advanced technology, and robust construction, making it a top choice for families looking to enhance their home's heating system. With its energy-saving innovations and commitment to reliability, the Merit Series stands as an exemplary option in today’s market.
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