The ML180UHE series units are classified as fan−assisted Category I furnaces when vertically vented according to the latest edition of National Fuel Gas Code (NFPA 54 / ANSI Z223.1) in the USA. A fan−assisted Category I fur- nace is an appliance equipped with an integral mechanical means to either draw or force combustion products through the combustion chamber and/or heat exchanger. The ML180UHE is not approved for use with horizontal venting.

NOTE − Use these instructions as a guide. They do not su- persede local codes. This furnace must be vented accord- ing to all local codes these installation instructions, and the provided venting tables in these instructions

The venting tables in this manual were extracted from the National Fuel Gas Code (NFPA 54 / ANSI Z223.1) and are provided as a guide for proper vent installation. Proper ap- plication, termination, construction and location of vents must conform to local codes having jurisdiction. In the ab- sence of local codes, the NFGC serves as the defining doc- ument.

Use self−drilling sheet metal screws or a mechanical fas- tener to firmly secure the vent pipe to the round collar of the flue transition. If self−drilling screws are used to attach the vent pipe, it is recommended that three be used. Drive one self−drilling screw through the front and one through each side of the vent pipe and collar. See figure 23.

Install the first vent connector elbow at a minimum of six inches (152 mm) from the furnace vent outlet. See figure 23.

lining system or dedicated gas vent. Unlined masonry chimneys are prohibited. See figures 24 and 25 for com- mon venting.

A chimney with one or more sides exposed to the outside of the structure is considered to be an exterior chimney.

An exterior masonry chimney that is not tile−lined must be lined with B1 vent or a listed insulated flexible metal vent. An exterior tile−lined chimney that is sealed and capped may be lined with a listed uninsulated flexible metal vent. If the existing chimney will not accommodate a listed metal liner, either the chimney must be rebuilt to accommodate one of these liners or an alternate approved venting meth- od must be found.

Insulation for the flexible vent pipe must be an encapsu- lated fiberglass sleeve recommended by the flexible vent pipe manufacturer. See figure 24.

Refer to the tables and the venting information contained in these instructions to properly size and install the venting system.

IMPORTANT

Once the venting system is installed, attach the connected Vent" warning sticker to a visible area of the plenum near the vent pipe. See figure 23. The warning sticker is provided in the bag assembly. Or- der kit 66W04 for additional stickers.

Venting Using a Masonry Chimney

The following additional requirements apply when a lined masonry chimney is used to vent this furnace.

Masonry chimneys used to vent Category I central fur- naces must be either tile-lined or lined with a listed metal

WARNING

Asphyxiation hazard. The exhaust vent for this fur- nace must be securely connected to the furnace flue transition at all times.

VENT CONNECTION UPFLOW AND HORIZONTAL POSITION

 

“DISCONNECTED VENT”

 

WARNING

 

STICKER

 

VENT PIPE

 

(min. 6" length)

 

“DISCONNECTED VENT”

 

WARNING

 

STICKER

 

FLUE TRANSITION

 

COLLAR

 

 

FLUE

VENT PIPE

TRANSITION

COLLAR

(min. 6" length)

FIGURE 23

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Lenox Lennox Merit Series Gas Furnace Upflow/Horizontal air discharge Vent Connection Upflow and Horizontal Position
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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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