TABLE 6

 

 

DIAGNOSTIC CODES

 

Diagnostic LEDs are labeled DS1 and DS2. See figure 4 for location of diagnostic LEDs.

 

 

 

DS1

DS2

DESCRIPTION

SIMULTANEOUS

SIMULTANEOUS

Power on − Normal operation.

SLOW FLASH

SLOW FLASH

Also signaled during cooling and continuous fan.

SIMULTANEOUS

SIMULTANEOUS

Normal operation − signaled when heating demand initiated at thermostat.

 

 

FAST FLASH

FAST FLASH

 

SLOW FLASH

ON

Primary, secondary, backup secondary or rollout limit switch open. Limits must

close within 3 minutes or unit goes into 1 hour Watchguard.

 

 

 

 

Low prove switch open;

OFF

SLOW FLASH

OR: Blocked inlet/exhaust vent;

 

 

OR: Low prove switch closed prior to activation of combustion air inducer.

 

 

 

 

 

High prove switch open;

OFF

FAST FLASH

OR: Blocked inlet/exhaust vent;

 

 

OR: High prove switch closed prior to activation of combustion air inducer.

 

 

 

ALTERNATING

ALTERNATING

Watchguard −− burners failed to ignite; OR limit open more than 3 minutes;

OR lost flame sense 5 times in one heating cycle;

SLOW FLASH

SLOW FLASH

OR pressure switch opened 5 times in one heating cycle.

 

 

 

 

 

SLOW FLASH

OFF

Flame sensed without gas valve energized.

ON

ON

 

ON

OFF

Circuit board failure or control wired incorrectly. Check 24 and 115 volts to board.

OFF

ON

 

 

 

 

FAST FLASH

SLOW FLASH

Main power polarity reversed. Switch line and neutral.

SLOW FLASH

FAST FLASH

Low flame signal. Measures below 0.23 microAmps. Replace flame sense rod.

 

 

The following conditions are sensed during the ignitor warm−up period only:

 

 

1) Improper main ground;

ALTERNATING

ALTERNATING

2) Broken ignitor; OR: Open ignitor circuit;

FAST FLASH

FAST FLASH

3) Line voltage below 75 volts.

 

 

(If voltage lower than 75 volts prior to ignitor warm-up, control will signal waiting on

 

 

call from thermostat, and will not respond.

 

 

 

NOTE − Slow flash rate equals 1 Hz (one flash per second). Fast flash rate equals 3 Hz (three flashes per second). Low flame sense current = 0.17−0.22 microAmps.

B−Blower Compartment

1. Blower Motor (B3) and Capacitor (C4)

All G61MP units use direct drive blower motors. All motors are 120V permanent split capacitor motors to ensure maxi- mum efficiency. Ratings for capacitors will be on motor nameplate. See SPECIFICATIONS section for motor speci- fications.

NOTE − Shafts on 1 HP motors have 2 flat sides and are matched with blower wheels with 2 set screws.

2. Secondary Limit Controls (S21)

The secondary limits (S21) on G61MP units are located in the blower compartment on the back side of the blower housing. See figure 5. All G61MP units are equipped with two secon- dary limts. When excess heat is sensed in the blower compart- ment, the limit will open. If the limit is open, the furnace control energizes the supply air blower and closes the gas valve. The limit automatically resets when unit temperature returns to nor- mal. The switch is factory set to open at 125°F and cannot be adjusted.

SUPPLY AIR BLOWER

AND SECONDARY LIMITS

SECONDARY

LIMIT (S)

MOTOR/BLOWER

ASSEMBLY

CAPACITOR

To Remove Blower From Unit: Disconnect Power, Remove Control

Box, Remove Bolts and Unplug Motor Wires From Control Board.

Then Slide Out Front of Unit.

FIGURE 5

Page 11

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Image 11
Lennox International Inc G61MP Blower Compartment Blower Motor B3 and Capacitor C4, Secondary Limit Controls S21

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.