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

Page 41

Troubleshooting: Cooling Sequence of Operation

COOLING SEQUENCE OF OPERATION

NORMAL COOLING MODE

 

 

ABNORMAL COOLING MODE

 

 

 

 

 

 

 

 

 

 

 

 

POWER ON

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IGNITION CONTROL MAIN POWER ON.

 

 

 

 

 

 

 

 

 

 

NO

 

GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.

 

CONTROL SELF DIAGNOSTIC CHECK.

 

INDOOR BLOWER OFF WITH NORMAL DELAY.

 

IS CONTROL OPERATING NORMALLY?

 

 

SIGNAL CIRCUIT BOARD FAILURE AT LED.

 

 

 

YES

 

 

 

 

INTERRUPT MAIN POWER TO RESET CONTROL.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NO

 

 

 

 

 

 

 

 

 

 

LED FLASHES CODE 2 IMPROPER GROUND

 

IS THERE A PROPER GROUND?

 

 

CONTROL WILL CONTINUE TO CALL FOR COOLING

 

 

 

YES

 

 

 

 

IN THIS CONDITION.

 

 

 

 

NO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LED FLASHES CODE 1 POLARITY REVERSED

 

 

 

 

 

 

 

 

 

IS POLARITY CORRECT?

 

CONTROL WILL CONTINUE TO CALL FOR COOLING IN

 

 

 

 

 

 

YES

 

 

 

 

THIS CONDITION.

 

 

 

 

 

 

 

 

 

 

 

 

 

NO

 

 

 

 

 

 

 

IS VOLTAGE

 

 

 

LED FLASHES CODE 13 LOW VOLTAGE. CONTROL

 

 

 

 

 

 

 

 

 

ABOVE 70 VOLTS?

 

 

 

WILL CONTINUE TO CALL FOR COOLING

 

 

 

 

 

 

 

 

 

YES

 

 

 

 

IN THIS CONDITION.

 

 

 

 

 

 

 

 

 

 

 

NO

 

LED FLASHES CODE 8 ROLLOUT SWITCH OPEN. GAS

 

 

 

 

 

 

 

 

 

 

 

 

VALVE OFF. COMBUSTION AIR INDUCER ON. INDOOR

ROLLOUT SWITCH MONITORED CONTINUOUSLY.

 

 

 

 

BLOWER ON. SEQUENCE HOLDS UNTIL ROLLOUT SWITCH

IS ROLLOUT SWITCH CLOSED?

 

 

 

CLOSES AND MAIN POWER IS INTERRUPTED OR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

THERMOSTAT IS CYCLED OFF/ON FOR 1 SEC. MINIMUM.

 

 

YES

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LED: SLOW FLASH RATE REMAINS UNCHANGED

THROUGHOUT COOLING CYCLE.

THERMOSTAT CALLS FOR COOLING.

COMPRESSOR CONTACTOR AND SYSTEM FAN

ENERGIZED WITH 2-SECOND DELAY

(COOLING SPEED). EAC TERM. ENERGIZED.

THERMOSTAT OPENS.

COMPRESSOR OFF.

SYSTEM FAN AND EAC TERM. OFF

WITH 45-SECOND DELAY.

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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 ValveShipping and Packing List Safety InformationML180UHE Gas Furnace 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. dropRight−Side Air Discharge Horizontal ApplicationLeft−Side Air Discharge Electrostatic Discharge ESD Interior MAKE−UP BOX InstallationElectrical 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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