Lennox International Inc Merit Series Gas Furnace installation instructions Setting Equipment

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Setting Equipment

WARNING

Do not install the furnace on its front or its back. Do not connect the return air ducts to the back of the fur- nace. Doing so will adversely affect the operation of the safety control devices, which could result in per- sonal injury or death.

The ML180UH gas furnace can be installed as shipped in either the upflow position or the horizontal position. Select a location that allows for the required clearances that are listed on the unit nameplate. Also consider gas supply connections, electrical supply, vent connection, and installation and service clearances [24 inches (610

mm)at unit front]. The unit must be level.

NOTE − Units with 1/2 hp blower motors are equipped with three flexible legs and one rigid leg. See figure 7. The rigid leg is equipped with a shipping bolt and a flat white plastic washer (rather than the rubber mounting grommet used with a flexible mounting leg). The bolt and washer must be removed before the furnace is placed into opera- tion. After the bolt and washer have been removed, the rig- id leg will not touch the blower housing.

ML180UH09048B with 1/2 HP

BLOWER MOTOR

RIGID LEG

remove shipping bolt and washer

FIGURE 7

Upflow Applications

Allow for clearances to combustible materials as indicated on the unit nameplate. Minimum clearances for closet or al- cove installations are shown in figure 8.

Upflow Application Installation Clearances

 

Top

Left Side

Right Side

 

Bottom

Type of Vent

Type C

Type B1

Connector

 

 

 

 

 

 

 

 

Top

1 in. (25 mm)

1 in. (25 mm)

 

 

 

*Front

2−1/4 in. (57 mm)**

2−1/4 in. (57 mm)

 

 

 

Back

0

0

 

 

 

Sides

0†

0

 

 

 

Vent

6 in. (152 mm)

1 in. (25 mm)

 

 

 

Floor

0‡

0‡

 

 

 

*Front clearance in alcove installation must be 24 in. (610 mm). Maintain a minimum of 24 in. (610 mm) for front service access. ** 4−1/2 in. if single wall vent pipe is used.

‡For installation on a combustible floor, do not install the furnace directly on carpeting, tile or other combustible materials other than wood flooring.

†Left side requires 3 inches if a single wall vent is used on 14−1/2 in. cabinets, or 2inches if a single wall vent pipe is used on 17−1/2 in. cabinets.

FIGURE 8

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Contents Table of Contents Installation Instructions ML180UHTOP View Unit Dimensions − inches mmParts Arrangement Safety Information ML180UH Gas FurnaceShipping and Packing List General Use of Furnace as Construction HeaterCombustion, 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 Duct System FiltersUpflow Position VentingTop 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 18 − The common vent diameter must always be at least as Cated or common venting system, you must inspectFeet FAN + FAN FAN + NAT 112 175 169 278 Carbon Monoxide Poisoning Hazard − In some localities, codes may require the installation Ers or straps. Install a drip leg in vertical pipe runs toGas 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 Integrated Control Typical ML180UH Field Wiring DiagramUnit Start−Up For Your Safety Read Before LightingGas Pressure Adjustment Proper CombustionHigh Altitude Manifold Pressure Settings at all Altitudes Other Unit AdjustmentsNo Jumper Heat FAN-OFF Time in Seconds750 453 900680 8851391 Single Side Return Air − Air volumes in bold require field860 653Electrical SHOCK, Fire Or Explosion Hazard ServiceHeat Exchanger Removal ML180UH BURNER, Combustion AIR Inducer Assembly−090, −110 −135 units −045 and −070 unitsPage Repair Parts List Planned ServiceDescription Integrated Control Diagnostic CodesNormal Heating Mode Abnormal Heating Mode Troubleshooting Heating Sequence of OperationHeating Sequence Normal Cooling Mode Abnormal Cooling Mode Troubleshooting Cooling Sequence of OperationContinuous Heat Speed FAN Sequence of Operation Troubleshooting Continuous 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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