Return Air −− Upflow Applications

Return air can be brought in through the bottom or either side of the furnace installed in an upflow application. If the furnace is installed on a platform with bottom return, make an airtight seal between the bottom of the furnace and the platform to ensure that the furnace operates properly and safely. The furnace is equipped with a removable bottom panel to facilitate installation.

Markings are provided on both sides of the furnace cabinet for installations that require side return air. Cut the furnace cabinet at the maximum dimensions shown on page 2.

NOTE − 60C and 60D units that require air volumes over 1800 cfm (850 L/s) must have one of the following:

1 − Single side return air with transition to accommodate 20 x 25 x 1 in. (508 x 635 x 25 mm) cleanable air filter. (Re- quired to maintain proper air velocity.) See figure 9.

2 − Single side return air with optional return airbase. See fig- ure 10.

3 − Bottom return air.

4 − Return air from both sides.

5 − Bottom and one side return air.

Refer to Engineering Handbook for additional information.

Single Side Return Air

(with transition and filter)

20” X 25” X 1”

(508mm X 635mm X 25mm)

Cleanable Filter

Return Air

Plenum

AIR FLOW

Transition

FIGURE 9

Optional Return Air Base

(Upflow Applications Only −− For use with A, B, C and D cabinets)

 

FURNACE

 

 

FRONT

 

 

 

IF BASE

 

 

IS USED

 

 

WITHOUT

 

INDOOR AIR

IAQ CABINET,

 

A SINGLE

 

QUALITY

RETURN AIR

 

CABINET

 

PLENUM

AIR FLOW

(PCO, Filter

MUST

 

Cabinet, etc.)

COVER BOTH

 

 

UNIT AND

 

 

RETURN

 

 

AIR BASE

 

 

OPENINGS

 

OPTIONAL

 

14−1/2 (368) A Width (65W75)

RETURN

17−1/2 (446) B Width (50W98)

AIR BASE

21 (533) C Width (50W99)

 

24−1/2 (622) D Width (51W00)

 

3−1/4

 

 

1 23 (584)

 

 

 

 

 

Overall

 

 

 

(83)

 

 

1 Minimum

 

 

(Maximum)

 

 

 

 

 

 

11 (279)

 

 

1 Unit side return air

2

Maximum

1 22−7/16

 

 

 

 

14 (356)

(570)

 

 

Opening

 

 

Overall

 

 

 

 

 

 

(Maximum)

7−1/4

5−5/8

SIDE RETURN

 

AIR OPENINGS

 

(143)

 

 

(184)

 

 

 

(Either Side)

 

 

 

 

 

 

 

 

23

 

 

3/4

 

 

 

(584)

 

 

 

 

 

26−7/8

 

 

(19)

 

 

 

(683)

 

 

 

SIDE VIEW

NOTE− Optional Side Return Air Filter Kits are not for use with Optional Return Air Base.

1Both the unit return air opening and the base return air opening must be covered by a single plenum or IAQ cabinet.

Minimum unit side return air opening dimensions for units requiring 1800 cfm or more of air (W x H): 23 x 11 in. (584 x 279 mm). The opening can be cut as needed to accommodate plenum or IAQ cabinet while maintaining dimensions shown.

Side return air openings must be cut in the field. There are cutting guides stenciled on the cabinet for the side return air

opening. The size of the opening must not extend beyond the markings on the furnace cabinet.

2To minimize pressure drop, the largest opening height possible (up to 14 inches 356 mm) is preferred.

FIGURE 10

Page 10

Page 9 Page 11
Page 10
Image 10
Lenox ML180UHE, Lennox Merit Series Gas Furnace Upflow/Horizontal air discharge installation instructions Return Air
Page 9 Page 11

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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