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

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Unconfined Space

An unconfined space is an area such as a basement or large equipment room with a volume greater than 50 cubic feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the com- bined input rating of all appliances installed in that space. This space also includes adjacent rooms which are not separated by a door. Though an area may appear to be un- confined, it might be necessary to bring in outdoor air for combustion if the structure does not provide enough air by infiltration. If the furnace is located in a building of tight construction with weather stripping and caulking around the windows and doors, follow the procedures in the air from outside section.

Confined Space

A confined space is an area with a volume less than 50 cu- bic feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the combined input rating of all appliances installed in that space. This definition includes furnace closets or small equipment rooms.

When the furnace is installed so that supply ducts carry air circulated by the furnace to areas outside the space contain- ing the furnace, the return air must be handled by ducts which are sealed to the furnace casing and which terminate outside the space containing the furnace. This is especially important when the furnace is mounted on a platform in a confined space such as a closet or small equipment room. Even a small leak around the base of the unit at the platform or at the return air duct connection can cause a potentially dangerous negative pressure condition. Air for combustion and ventilation can be brought into the confined space either from inside the building or from outside.

EQUIPMENT IN CONFINED

SPACE ALL AIR FROM INSIDE

CHIMNEY

OR GAS

VENT

 

WATER

FURNACE

HEATER

 

OPENINGS

 

(To Adjacent

 

Room)

NOTE − Each opening shall have a free area of at least one square inch (645 mm2) per 1,000 Btu (.29 kW) per hour of the total input rat- ing of all equipment in the enclosure, but not less than 100 square inches (64516 mm2).

FIGURE 3

Air from Inside

If the confined space that houses the furnace adjoins a space categorized as unconfined, air can be brought in by providing two permanent openings between the two spaces. Each opening must have a minimum free area of 1 square inch (645 mm2) per 1,000 Btu (.29 kW) per hour of total input rating of all gas−fired equipment in the confined space. Each opening must be at least 100 square inches (64516 mm2). One opening shall be within 12 inches (305

mm)of the top of the enclosure and one opening within 12 inches (305 mm) of the bottom. See figure 3.

Air from Outside

If air from outside is brought in for combustion and ventila- tion, the confined space must have two permanent open- ings. One opening shall be within 12 inches (305 mm) of the top of the enclosure and one opening within 12 inches (305

mm)of the bottom. These openings must communicate di- rectly or by ducts with the outdoors or spaces (crawl or at- tic) that freely communicate with the outdoors or indirectly through vertical ducts. Each opening shall have a minimum free area of 1 square inch (645 mm2) per 4,000 Btu (1.17 kW) per hour of total input rating of all equipment in the en- closure. See figures 4 and 5. When communicating with the outdoors through horizontal ducts, each opening shall have a minimum free area of 1 square inch (645 mm2) per 2,000 Btu (.56 kW) per total input rating of all equipment in the enclosure. See figure 6.

When ducts are used, they shall be of the same cross−sec- tional area as the free area of the openings to which they connect. The minimum dimension of rectangular air ducts shall be no less than 3 inches (75 mm). In calculating free area, the blocking effect of louvers, grilles, or screens must be considered. If the design and free area of protective cov- ering is not known for calculating the size opening required, it may be assumed that wood louvers will have 20 to 25 per- cent free area and metal louvers and grilles will have 60 to 75 percent free area. Louvers and grilles must be fixed in the open position or interlocked with the equipment so that they are opened automatically during equipment operation.

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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 BoxML180UHE 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 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 PipingLeft−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 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

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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