Lennox International Inc Merit Series Gas Furnace ML180UH BURNER, Combustion AIR Inducer Assembly

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Cleaning the Heat Exchanger and Burners

NOTE − Use papers or protective covering in front of the fur- nace during cleaning.

1 − Turn off both electrical and gas power supplies to fur- nace.

2 − Remove flue pipe and top cap (some applications top cap can remain) from the unit.

3 − Label the wires from gas valve, rollout switches, prima- ry limit switch and make−up box then disconnect them.

4 − Remove the screws that secure the combustion air in- ducer/pressure switch assembly to the collector box. Carefully remove the combustion air inducer to avoid damaging blower gasket. If gasket is damaged, it must be replaced to prevent leakage.

5 − Remove the collector box located behind the combus- tion air inducer. Be careful with the collector box gas- ket. If the gasket is damaged, it must be replaced to prevent leakage.

6 − Disconnect gas supply piping. Remove the screw se- curing the burner box cover and remove cover. Re- move the four screws securing the burner manifold as- sembly to the vestibule panel and remove the assembly from the unit.

7 − Remove screws securing burner box and remove burner box.

8 − NOX units only − Remove screw securing NOX insert. Remove NOX insert. See figure 38.

 

ML180UH BURNER, COMBUSTION AIR INDUCER ASSEMBLY &

 

HEAT EXCHANGER REMOVAL

 

 

Gasket

 

 

Flue Transition

 

 

Pressure Switch

 

Rollout Switches

 

(−090, −110 −135 units)

 

Rollout Switches

Ignitor

Heat Exchanger

(−045 and −070 units)

 

 

 

Orifice Plate

Collector Box

 

Combustion Air Inducer

 

Sensor

 

 

 

 

Retention Rings

 

 

Cross Over

 

Manifold And Gas Valve

 

FIGURE 37

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Contents Installation Instructions ML180UH Table of ContentsUnit Dimensions − inches mm TOP ViewParts Arrangement Safety Information ML180UH Gas FurnaceShipping and Packing List 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 Horizontal Application Installation Clearances Top Left RightEnd Bottom Filters Duct SystemVenting Upflow PositionTop Vent Discharge Left Side Vent DischargeHorizontal Left Position Horizontal Right PositionSide Vent Discharge 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 Ers or straps. Install a drip leg in vertical pipe runs to − In some localities, codes may require the installationGas Piping Every 8 to 10 feet 2.44 to 3.01 m with suitable hangHorizontal Application Left−Side Air DischargeRight−Side Air Discharge Interior MAKE−UP BOX Installation ElectricalElectrostatic Discharge ESD Thermostat Designations ML180UH Schematic Wiring Diagram and Sequence of Operation Typical ML180UH Field Wiring Diagram Integrated ControlFor Your Safety Read Before Lighting Unit Start−UpGas Pressure Adjustment Proper CombustionHigh Altitude Other Unit Adjustments Manifold Pressure Settings at all AltitudesHeat FAN-OFF Time in Seconds No Jumper453 900 750680 885Single Side Return Air − Air volumes in bold require field 1391860 653Service Electrical SHOCK, Fire Or Explosion HazardML180UH BURNER, Combustion AIR Inducer Assembly Heat Exchanger Removal−090, −110 −135 units −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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