Lennox International Inc Merit Series Gas Furnace Heat FAN-OFF Time in Seconds, No Jumper

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HEAT FAN-OFF TIME IN SECONDS

 

 

 

 

 

 

 

 

NO JUMPER

 

 

 

 

 

 

 

 

 

To adjust fan−off timing, reposition jumper across pins to

 

 

 

 

 

achieve desired setting.

 

 

 

 

60 Second

90 Second

120 Second

180 Second

off Time

off Time

 

off Time

 

off Time

60

90

120

180

60

90

120

180

60

90

120

180

60

90

120

180

FIGURE 36

Thermostat Heat Anticipation

Set the heat anticipator setting (if adjustable) according to the amp draw listed on the wiring diagram that is attached to the unit.

NOTE − Do not secure the electrical conduit directly to the air ducts or structure.

Electrical

1 − Check all wiring for loose connections.

2 − Check for the correct voltage at the furnace (furnace operating). Correct voltage is 120VAC + 10%.

3 − Check amp−draw on the blower motor with inner blow- er panel in place.

Unit Nameplate__________Actual__________

Blower Speeds

Follow the steps below to change the blower speeds.

1 − Turn off electrical power to furnace.

2 − Remove blower access panel.

3 − Disconnect existing speed tap at integrated control speed terminal.

NOTE − Termination of any unused motor leads must be insulated.

4 − Place unused blower speed tap on integrated control PARK" terminal or insulate.

5 − Refer to blower speed selection chart on unit wiring dia- gram for desired heating or cooling speed. See Blower performance data beginning on the next page.

6 − Connect selected speed tap at integrated control speed terminal.

7 − Resecure blower access panel.

8 − Turn on electrical power to furnace.

9 − Recheck temperature rise.

Electronic Ignition

The integrated control has an added feature of an internal Watchguard control. The feature serves as an automatic re- set device for integrated control lockout caused by ignition failure. This type of lockout is usually due to low gas line pressure. After one hour of continuous thermostat demand for heat, the Watchguard will break and remake thermostat demand to the furnace and automatically reset the inte- grated control to begin the ignition sequence.

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Contents Installation Instructions ML180UH Table of ContentsUnit Dimensions − inches mm TOP ViewParts Arrangement Shipping and Packing List Safety InformationML180UH Gas Furnace Use of Furnace as Construction Heater GeneralCombustion, Dilution & Ventilation Air Equipment in Confined Space ALL AIR from Inside Equipment in Confined Space Setting Equipment Return Air Plenum End Bottom Horizontal Application Installation Clearances Top LeftRight Filters Duct SystemVenting Upflow PositionTop Vent Discharge Left Side Vent DischargeSide Vent Discharge Horizontal Left PositionHorizontal Right Position Vent Connection Upflow and Horizontal Position Common Venting Using Metal−Lined Masonry Chimney −1/2 Cated or common venting system, you must inspect 18 − The common vent diameter must always be at least asFeet FAN + FAN FAN + NAT 112 175 169 278 Carbon Monoxide Poisoning Hazard Ers or straps. Install a drip leg in vertical pipe runs to − In some localities, codes may require the installationGas Piping Every 8 to 10 feet 2.44 to 3.01 m with suitable hangRight−Side Air Discharge Horizontal ApplicationLeft−Side Air Discharge Electrostatic Discharge ESD Interior MAKE−UP BOX InstallationElectrical Thermostat Designations ML180UH Schematic Wiring Diagram and Sequence of Operation Typical ML180UH Field Wiring Diagram Integrated ControlFor Your Safety Read Before Lighting Unit Start−UpHigh Altitude Gas Pressure AdjustmentProper Combustion Other Unit Adjustments Manifold Pressure Settings at all AltitudesHeat FAN-OFF Time in Seconds No Jumper453 900 750680 885Single Side Return Air − Air volumes in bold require field 1391860 653Service Electrical SHOCK, Fire Or Explosion HazardML180UH BURNER, Combustion AIR Inducer Assembly Heat Exchanger Removal−090, −110 −135 units −045 and −070 unitsPage Planned Service Repair Parts ListIntegrated Control Diagnostic Codes DescriptionTroubleshooting Heating Sequence of Operation Normal Heating Mode Abnormal Heating ModeHeating Sequence Troubleshooting Cooling Sequence of Operation Normal Cooling Mode Abnormal Cooling ModeTroubleshooting Continuous Fan Sequence of Operation Continuous Heat Speed FAN Sequence of Operation

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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