9 − Remove screws from both sides, top and bottom of vestibule panel.

10 −Remove heat exchanger. It may be necessary to spread cabinet side to allow more room. If so, remove five screws from the left side or right side of cabinet. See figure 39.

11 − Backwash using steam. Begin from the burner opening on each clam. Steam must not exceed 275°F.

12−To clean burners, run a vacuum cleaner with a soft brush attachment over the face of burners. Visually inspect in- side the burners and crossovers for any blockage caused by foreign matter. Remove any blockage. Figure 37 shows burner detail.

13−To clean the combustion air inducer visually inspect and using a wire brush clean where necessary. Use com- pressed air to clean off debris and any rust.

14−Reinstall heat exchanger in vestibule. (Replace the five screws in the cabinet from step 10 if removed).

15−NOx units only − Replace NOx inserts.

16−Reinstall collector box and combustion air assembly. Reinstall all screws to the collector box and combustion air inducer. Failure to replace all screws may cause leaks. Inspect gaskets for any damage and replace if necessary.

17−Reinstall burner box, manifold assembly and burner box cover.

ML180UH NOx INSERTS

NOx Insert

FIGURE 38

Remove 5 screws if necessary

(either side of cabinet)

1

2

3

4

5

FIGURE 39

18−Reconnect all wires.

19−Reconnect top cap and vent pipe to combustion air in- ducer outlet.

20−Reconnect gas supply piping.

21−Turn on power and gas supply to unit.

22−Set thermostat and check for proper operation.

23−Check all piping connections, factory and field, for gas leaks. Use a leak detecting solution or other preferred means.

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.

24 −If a leak is detected, shut gas and electricity off and repair leak.

25 −Repeat steps 24 and 26 until no leaks are detected.

26 −Replace access panel.

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Lennox International Inc Merit Series Gas Furnace installation instructions
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Merit Series Gas Furnace specifications

Lennox International Inc. is a leading name in the heating and cooling industry, and their Merit Series Gas Furnace embodies the commitment to quality and efficiency that the company is known for. The Merit Series is designed to provide reliable heating in a sustainable manner, making it an excellent choice for homeowners seeking comfort without excessive energy bills.

One of the standout features of the Merit Series Gas Furnace is its efficiency ratings. The units in this series typically boast Annual Fuel Utilization Efficiency (AFUE) ratings of up to 95%. This level of efficiency means that the furnace converts a significant portion of the fuel it uses into heat, ultimately lowering operating costs. Such energy-efficient performance is not only beneficial for the wallet but also promotes environmental sustainability.

The Merit Series also incorporates advanced technologies that enhance its operation. The inclusion of a multi-speed blower motor is a notable feature that provides thoughtful airflow management throughout the home. By adjusting the speed according to the heating needs, the furnace optimizes comfort levels while minimizing noise and energy consumption. Homeowners can enjoy a warm environment without the disruptive sounds often associated with traditional furnaces.

Moreover, the Merit Series comes equipped with durable construction materials designed to withstand the test of time. From the robust heat exchanger to the heavy-gauge cabinet, Lennox focuses on longevity and reliability. This ensures that homeowners can trust their furnace to operate effectively even in the harshest winter conditions.

Safety features are also integral to the design of the Merit Series Gas Furnace. With an integrated Flame Sensor and a built-in safety shut-off system, the furnace ensures that any irregularities in operation are promptly detected and addressed. Such measures provide peace of mind for families using the heating system throughout the cold months.

Installation and maintenance are further simplified with the Merit Series. Its design facilitates easier access for HVAC professionals, allowing for quicker installations and routine service, ensuring that homeowners spend less time and money on upkeep.

In conclusion, Lennox International Inc.'s Merit Series Gas Furnace combines efficiency, advanced technology, and robust construction, making it a top choice for families looking to enhance their home's heating system. With its energy-saving innovations and commitment to reliability, the Merit Series stands as an exemplary option in today’s market.
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