Lenox Lennox Merit Series Gas Furnace Manual & Installation Instructions
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E 2011 Lennox Industries Inc.

Dallas, Texas, USA

AIR FLOW

UPFLOW

AIR FLOW

AIR FLOW

HORIZONTAL LEFT

HORIZONTAL RIGHT

INSTALLATION

INSTRUCTIONS

ML180UHE

MERIT® SERIES GAS FURNACE

UPFLOW / HORIZONTAL AIR DISCHARGE

506810−01

06/2011

Supersedes 506732−01

Litho U.S.A.

THIS MANUAL MUST BE LEFT WITH THE HOMEOWNER FOR FUTURE REFERENCE

This is a safety alert symbol and should never be ignored. When you see this symbol on labels or in manuals, be alert to the potential for personal injury or death.

WARNING

Improper installation, adjustment, alteration, service or maintenance can cause property damage, person- al injury or loss of life. Installation and service must be performed by a licensed professional installer (or equivalent), service agency or the gas supplier.

CAUTION

As with any mechanical equipment, personal injury can result from contact with sharp sheet metal edges. Be careful when you handle this equipment.

Table of Contents

Unit Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Parts Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

ML180UHE Gas Furnace . . . . . . . . . . . . . . . . . . . . . . . . . 4

Shipping and Packing List . . . . . . . . . . . . . . . . . . . . . . . . 4

Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Use of Furnace as a Construction Heater . . . . . . . . . . . 5 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Combustion, Dilution & Ventilation Air . . . . . . . . . . . . . . 6

Setting Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Duct System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Venting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Integrated Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Unit Start−Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Gas Pressure Adjustment . . . . . . . . . . . . . . . . . . . . . . . . 30

High Altitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Proper Combustion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Other Unit Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Blower Performance Data . . . . . . . . . . . . . . . . . . . . . . . . 33

Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Planned Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Repair Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Integrated Control Diagnostic Codes . . . . . . . . . . . . . . . 38

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

06/11

 

506810−01

*2P0611*

Page 1

*P506810-01*

 

 

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Contents Table of Contents Installation Instructions ML180UHETOP View Unit Dimensions − inches mmMake−Up Box Heat Exchanger Combustion Air Inducer Parts ArrangementBurner Box Gas ValveML180UHE Gas Furnace Safety InformationShipping 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 Right Horizontal Application Installation Clearances Top LeftEnd Bottom Typical Horizontal ApplicationDuct System FiltersUpflow Position VentingTop Vent Discharge Left Side Vent DischargeHorizontal Left Position Horizontal Left Position Horizontal Right PositionSide Vent Discharge Side Vent Discharge − no modifications necessaryVent 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 130 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 Gas supply piping should not allow more than 0.5W.C. dropLeft−Side Air Discharge Horizontal ApplicationRight−Side Air Discharge Electrical Interior MAKE−UP BOX InstallationElectrostatic Discharge ESD Thermostat Designations ML180UHE Schematic Wiring Diagram and Sequence of Operation Integrated Control Typical ML180UHE Field Wiring DiagramUnit Start−Up For Your Safety Read Before LightingGAS Meter Clocking Chart Gas Pressure AdjustmentProper Combustion High AltitudeManifold Pressure Settings at all Altitudes Other Unit AdjustmentsNo Jumper Heat FAN-OFF Time in Seconds995 1380975 115 945 1345Order to maintain proper air velocity Single Side Return Air − Air volumes in bold require field640 1940 420 1750 310 230Electrical SHOCK, Fire Or Explosion Hazard ServiceHeat Exchanger Removal ML180UHE BURNER, Combustion AIR Inducer Assembly−090, −110 −135 units −045 and −070 unitsRepair Parts List Planned ServiceRED LED Integrated Control Diagnostic CodesHeating Sequence of Operation Normal Heating Mode Abnormal Heating ModeHeating Sequence Cooling Sequence of Operation Normal Cooling Mode Abnormal Cooling ModeContinuous FAN Sequence of Operation Start−Up & Performance Check List Temperature Rise Cooling ModeUnit Operation Drain Line

Lennox Merit Series Gas Furnace Upflow/Horizontal air discharge, ML180UHE specifications

The Lenox ML180UHE is a reliable and efficient gas furnace that falls within the Lennox Merit Series. This model is designed for upflow or horizontal air discharge, making it versatile for various installation requirements. With its robust construction and advanced technology, the ML180UHE is ideal for homeowners seeking a dependable heating solution that combines comfort and efficiency.

One of the main features of the ML180UHE is its impressive 80% Annual Fuel Utilization Efficiency (AFUE) rating. This efficiency means that 80 cents of every dollar spent on fuel is used to heat your home while minimizing waste. This furnace is equipped with a multi-speed blower motor that enhances the overall air circulation in your home, providing consistent temperatures and improved comfort.

The ML180UHE features a durable heat exchanger made of high-quality materials, which ensures longevity and reliable performance. The design of the heat exchanger maximizes heat transfer efficiency, allowing the furnace to quickly warm your home while also maintaining optimal efficiency levels throughout its lifespan.

Lennox has integrated advanced technologies into the ML180UHE to enhance its operation and user experience. The unit is compatible with a variety of thermostats, including Lennox's innovative iComfort S30 Smart Thermostat, allowing for easy temperature control and programming capabilities. This smart technology can learn your preferences, optimize energy usage, and enable remote access through a smartphone app.

In addition to its energy efficiency, the ML180UHE offers quiet operation, making it an excellent choice for residential environments. The well-insulated cabinet helps to reduce noise levels, providing a peaceful indoor atmosphere.

Installation and maintenance are simplified with the ML180UHE due to its compact design and accessible components. The furnace is designed to fit into tight spaces, allowing for flexible installation options. Regular maintenance is uncomplicated, ensuring that homeowners can keep the unit running at peak performance with minimal effort.

Overall, the Lennox ML180UHE gas furnace provides users with a reliable, efficient, and quiet heating solution. With its combination of advanced technology, durable design, and ease of use, it is an excellent choice for anyone looking to enhance the comfort of their home while optimizing energy consumption.
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