Lenox Understanding Lennox Gas Furnace Parts Arrangement for Efficient Heating
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Parts Arrangement

Make−Up Box

 

Heat Exchanger

 

Combustion Air Inducer

 

Combustion Air Inducer

 

Pressure Switch

 

Burner Box

 

(includes sensor, ignitor

 

and rollout switches)

 

Gas Valve

 

Primary Limit

Control Box

(under

(includes integrated control,

combustion

interlock switch and transformer)

air inducer)

 

Upper Access Panel

 

 

Secondary Limits

Blower Access Panel

Blower Assembly

 

Power Choke

 

(4 and 5 Ton Only)

 

FIGURE 1

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Contents Table of Contents Installation Instructions ML180UHETOP View Unit Dimensions − inches mmGas Valve Parts ArrangementMake−Up Box Heat Exchanger Combustion Air Inducer Burner BoxSafety Information ML180UHE 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 Typical Horizontal Application Horizontal Application Installation Clearances Top LeftRight End BottomDuct System FiltersLeft Side Vent Discharge VentingUpflow Position Top Vent DischargeSide Vent Discharge − no modifications necessary Horizontal Left Position Horizontal Right PositionHorizontal Left Position Side Vent DischargeVent 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 Gas supply piping should not allow more than 0.5W.C. drop Ers or straps. Install a drip leg in vertical pipe runs to− In some localities, codes may require the installation Gas PipingHorizontal Application Left−Side Air DischargeRight−Side Air Discharge Interior MAKE−UP BOX Installation ElectricalElectrostatic 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 LightingHigh Altitude Gas Pressure AdjustmentGAS Meter Clocking Chart Proper CombustionManifold Pressure Settings at all Altitudes Other Unit AdjustmentsNo Jumper Heat FAN-OFF Time in Seconds1345 1380995 975 115 945230 Single Side Return Air − Air volumes in bold require fieldOrder to maintain proper air velocity 640 1940 420 1750 310Electrical SHOCK, Fire Or Explosion Hazard Service−045 and −070 units ML180UHE BURNER, Combustion AIR Inducer AssemblyHeat Exchanger Removal −090, −110 −135 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 Drain Line Cooling ModeTemperature Rise Unit Operation
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