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

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Leak Check

After gas piping is completed, carefully check all piping connections (factory− and field−installed) for gas leaks. Use a leak detecting solution or other preferred means.

NOTE − If emergency shutoff is necessary, shut off the main manual gas valve and disconnect the main power to the furnace. The installer should properly label these devices.

CAUTION

Some soaps used for leak detection are corrosive to certain metals. Carefully rinse piping thoroughly af- ter leak test has been completed. Do not use matches, candles, flame or other sources of ignition to check for gas leaks.

The furnace must be isolated by closing its individual manual shut-off valve and disconnecting from from the gas supply system during any pressure testing of the gas sup- ply system at pressures greater than 1/2 psig (3.48 kPa, 14 inches w.c.).

IMPORTANT

When testing pressure of gas lines, gas valve must be disconnected and isolated. See figure 28. Gas valves can be damaged if subjected to pressures greater than 1/2 psig (3.48 kPa, 14 inches w.c.).

MANUAL MAIN

ISOLATE

SHUT−OFF VALVE

GAS VALVE

WILL NOT HOLD

FURNACE

NORMAL TEST

 

PRESSURE

 

1/8 NPT PLUG

 

CAP

FIGURE 28

Electrical

ELECTROSTATIC DISCHARGE (ESD)

Precautions and Procedures

CAUTION

Electrostatic discharge can affect electronic com- ponents. Take precautions during furnace installa- tion and service to protect the furnace’s electronic controls. Precautions will help to avoid control ex- posure to electrostatic discharge by putting the fur- nace, the control and the technician at the same electrostatic potential. Neutralize electrostatic charge by touching hand and all tools on an un- painted unit surface, such as the gas valve or blower deck, before performing any service procedure.

The unit is equipped with a field make−up box on the left hand side of the cabinet. The make−up box may be moved to the right side of the furnace to facilitate installation. If the make−up box is moved to the right side, clip the wire ties that bundle the wires together. The excess wire must be pulled into the blower compartment. Secure the excess wire to the existing harness to protect it from damage.

INTERIOR MAKE−UP BOX INSTALLATION

Right Side

BOX

FIGURE 29

INTERIOR MAKE−UP BOX INSTALLATION

Left side

BOX

FIGURE 30

Refer to figure 32 for schematic wiring diagram and trou- bleshooting and figure 33 for field wiring.

The power supply wiring must meet Class I restrictions. Protected by either a fuse or circuit breaker, select circuit protection and wire size according to unit nameplate.

NOTE − Unit nameplate states maximum current draw. Maximum over−current protection allowed is 15 AMP.

Holes are on both sides of the furnace cabinet to facilitate wiring.

Install a separate (properly sized) disconnect switch near the furnace so that power can be turned off for servicing.

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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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