onds. After a total of five trials for ignition (including the ini- tial trial), the control goes into Watchguard−Flame Failure mode. After a 60−minute reset period, the control will begin the ignition sequence again.

The SureLight control board has an added feature that pro- longs the life of the ignitor. After a successful ignition, the SureLight control utilizes less power to energize the ignitor on successive calls for heat. The control continues to ramp down the voltage to the ignitor until it finds the lowest amount of power that will provide a successful ignition. This amount of power is used for 255 cycles. On the 256th call for heat, the control will again ramp down until the lowest power is determined and the cycle begins again.

Two Stage Operation / Thermostat Selection Jumper The control can be utilized in two modes: SINGLE−STAGE thermostat or TWO−STAGE thermostat. The thermostat selection jumper E20, located just below dip switches 1 through 4 (figure 4), must be positioned for the particular application. The jumper is factory set on

with a two−stage thermostat with two stage heat. Re−posi-

tion jumper to

age thermo-

stat with two stage heat.

 

While in the single−stage thermostat mode (single jumper setting), the burners will always fire on first−stage heat. The combustion air inducer will operate on low speed and in- door blower will operate on low heat speed. After a 10 min- ute recognition period, the unit will switch to second stage heat. While in the two−stage thermostat mode (two jumper setting) the burners will fire on first−stage heat. The com- bustion air inducer will operate on low speed and indoor blower will operate on low heat speed. The unit will switch to second−stage heat on call from the indoor thermostat. If there is a simultaneous call for first and second stage heat, the unit will fire on first stage heat and switch to second stage heat after 30 seconds of operation. See Sequence of Operation flow charts in the back of this manual for more detail.

Dip Switch Settings

Dip Switches 1 and 2 − Heating Fan off Delay − The fan on time of 45 seconds is not adjustable. Fan off time (time that the blower operates after the heat demand has been satis- fied) can be adjusted by flipping the dip switches 1 and 2 located on the SureLight integrated control. The unit is shipped with a factory fan off setting of 90 seconds. Fan off time will affect comfort and is adjustable to satisfy individual applications. For customized comfort, monitor the supply air temperature once the heat demand is satisfied. Note the supply air temperature at the instant the blower is de−ener- gized. Adjust the fan−off delay to achieve a supply air tem- perature between 90° − 110° at the instant the blower is de− energized. (Longer delay times allow for lower air tempera- ture, shorter delay times allow for higher air temperature). See table 1 for dip switch settings.

TABLE 1

Heating Fan Off Delay

Delay (Seconds)

Switch 1

Switch 2

 

 

 

 

60

Off

Off

 

 

 

90

Off

On

 

 

 

120

On

Off

 

 

 

180

On

On

Switch 3 − Second Stage Delay (Used with Single−Stage Thermostat Only) −− This switch is used to determine the second stage on delay when a single−stage thermostat is being used. The switch is factory−set in the ON position, which provides a 10−minute delay before second−stage heat is initiated. If the switch is toggled to the OFF position, it will provide a 15−minute delay before second−stage heat is initiated. This switch is only activated when the thermo- stat selector jumper is positioned for SINGLE−stage ther- mostat use.

Switch 4 − Cooling Fan off Delay − The fan on delay time of 2 seconds is not adjustable. Fan off time (time that the blower operates after the cool demand has been satisfied) can be adjusted by flipping dip switch 4. The unit is shipped with a factory fan off setting of 45 seconds. Fan off time will affect comfort and is adjustable to satisfy individual ap- plications. See table 2 for cool fan off time settings.

TABLE 2

Cooling Fan Off Delay

Delay (Seconds)

Switch 4

 

 

2

Off

 

 

45

On

 

 

Diagnostic LED’s (DS1 and DS2)

Two diagnostic LED’S are located on the two−stage inte- grated control board. See figure 4. These light flashes cor- respond with the codes detailed in table 6.

Factory Installed Jumper Y1 to Y2

A factory−installed jumper from Y1 to Y2 terminals on the integrated control board terminal strip must be clipped for two−stage cooling.

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Lennox International Inc G61MP specifications
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G61MP specifications

Lennox International Inc. has long been a leader in HVAC solutions, and the G61MP gas furnace exemplifies the company's commitment to innovation and energy efficiency. This high-efficiency gas furnace operates with an Annual Fuel Utilization Efficiency (AFUE) of up to 96%, allowing homeowners to save significantly on energy costs while maintaining a comfortable indoor environment.

One of the primary features of the G61MP is its modulating gas valve. This technology enables the furnace to operate at multiple levels of heating output, ensuring that it can adjust its performance according to the home’s heating demands. By modulating the heating output, the G61MP maximizes efficiency and minimizes energy waste, providing a consistent temperature and improved comfort.

The G61MP also incorporates advanced two-stage heating, which enhances its performance by reducing temperature fluctuations in the home. This feature is especially beneficial during transitional weather periods when heating needs may vary widely. With its ability to operate on a lower stage most of the time, the furnace can produce quieter operation and reduced energy consumption.

In terms of design, the G61MP includes a sealed combustion chamber that draws air from outside the home for combustion, enhancing safety and efficiency. This design feature eliminates the need for indoor air, improving indoor air quality. The furnace is also equipped with a high-efficiency ECM blower motor that not only boosts comfort but operates quietly and uses less electricity compared to traditional motors.

Further enhancing its efficiency, the G61MP utilizes a variable-speed blower, which allows for precise control of airflow throughout the home. This results in better humidity control and improved air distribution, providing an overall more comfortable environment.

The Lennox G61MP is compatible with the iComfort S30 smart thermostat, allowing homeowners to control their heating remotely, adjust settings based on their schedules, and access energy usage data. This connectivity transforms the G61MP into an integral part of a smart home ecosystem, facilitating energy conservation and comfort optimization.

Lastly, the G61MP is designed with durability in mind. Its robust construction and high-quality materials ensure reliable performance and lengthy service life. Homeowners can feel assured that they are investing in a heating solution that will meet their needs for many winters to come. In summary, the Lennox G61MP gas furnace stands out with its high efficiency, advanced technology, and user-friendly features, making it a top choice for homeowners seeking exceptional heating performance.
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