Lennox International Inc MERIT SERIES GAS FURNACE DOWNFLOW AIR DISCHARGE Repair Parts List

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Repair Parts List

The following repair parts are available through Lennox dealers. When ordering parts, include the complete furnace model number listed on the CSA nameplate −− Example: ML193DF04536B. All service must be performed by a licensed pro- fessional installer (or equivalent), service agency, or gas supplier.

Cabinet Parts

Heating Parts

Upper access panel

Flame Sensor

Blower access panel

Heat exchanger assembly

Top Cap

Gas manifold

Control Panel Parts

Combustion air inducer

 

Transformer

Gas valve

 

Integrated control board

Main burner cluster

 

Door interlock switch

Main burner orifices

 

Blower Parts

Pressure switch

Blower wheel

Ignitor

Motor

Primary limit control

Motor mounting frame

Flame rollout switches

Motor capacitor

 

Blower housing cutoff plate

 

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Contents Table of Contents Installation Instructions ML193DFML193DF ML193DF Unit Dimensions − inches mmML193DF Parts Arrangement BAG AssemblyControl BOX Blower MotorDirect Vent Installation NON−DIRECT Vent Safety InformationML193DF Gas Furnace Shipping and Packing ListUse of Furnace as Construction Heater Combustion, Dilution & Ventilation Air GeneralEquipment in Confined Space − ALL AIR from Inside Equipment in Confined Space − ALL AIR from Outside Shipping Bolt RemovalSetting Equipment Installation − Setting EquipmentFront Horizontal Back NC‡ NON−COMBUSTIBLE Floor Opening SizeSide View Combustible Flooring Base Opening Size− Seal the cabinet and check for air leaks Piping and Fittings Specifications Pipe & Fittings SpecificationsFilters Duct SystemOutdoor Termination Kits Usage Venting Practices Joint Cementing ProcedurePiping Suspension Guidelines ScheduleMinimum Vent Pipe Lengths Vent Piping GuidelinesML193DF MIN. Vent Length Model Maximum Allowable Intake or Exhaust Vent Length in Feet Typical Intake Pipe Connections Typical Exhaust Pipe ConnectionsIntake Exhaust Typical AIR Intake Pipe Connections Inches 305mm or 12 in mm Inside Corner DetailUS Installations1 Canadian Installations2 Direct Vent Roof Termination KIT − On field supplied terminations, a minimum distanceFLUSH−MOUNT Side Wall Termination KIT 51W11 51mm 76mm Vent Pipe Required to Adapt Reducer MAY beUnconditioned Space SupportTop View Front ViewExhaust NON−DIRECT Vent Roof Termination KIT 203mm − 305mmML193DF NON−DIRECT Vent Application Using Existing Chimney To drain ML193DF with Evaporator CoilTrap / Drain Assembly Using 1/2 PVC or 3/4 PVC Furnace Isolate GAS Valve Gas PipingGAS Pipe Capacity − FT3/HR kL/HR Electrical Precautions and ProceduresElectrostatic Discharge ESD Interior MAKE−UP BOX FACTORY− Installed Left Side MAKE−UPExterior MAKE−UP BOX BOX InsideThermostat Designations Typical ML193DF Field Wiring DiagramTypical ML193DF Wiring Diagram Unit Start−Up For Your Safety Read Before OperatingIntegrated Control Automatic Hot Surface Ignition SystemPage GAS Meter Clocking Chart Gas Pressure AdjustmentProper Combustion High Altitude Information2286m 3048m 2286 − 3038m73W37 73W81 68W68 74W90 74W91 69W73 Heat FAN-OFF Time in Seconds Other Unit AdjustmentsNo Jumper High Low In. w.g Cfm Watts Cfm Watts cfm Watts Blower DataElectrical SHOCK, Fire Or Explosion Hazard ServicePage Ignition Control Board Diagnostic Codes Planned ServiceDiagnostic Codes LED #1 Red LED #2 GreenNormal Heating Mode Abnormal Heating Mode Troubleshooting Heating Sequence of OperationHeating Sequence of Operation Heating Sequence Normal Cooling Mode Abnormal Cooling Mode Troubleshooting Cooling Sequence of OperationCooling Sequence of Operation Continuous Heat Speed FAN Sequence of Operation Troubleshooting Continuous Fan Sequence of OperationRepair Parts List GAS Supply Start−Up & Performance Check ListReturn AIR Duct System Supply AIR Duct Intake / Exhaust PipeTotal External Static Drain Line Temperature RiseCondensate Line Thermostat Vent PipeLY BELOW. Keep Clear of ALL OBSTRUC- Tions Requirements for Commonwealth of Massachusetts