Lennox International Inc G61MP Improper ground to the unit, Main ground, Line voltage is below

Page 49

PROBLEM 1: UNIT FAILS TO OPERATE IN THE COOLING, HEATING, OR CONTINUOUS FAN MODE

Condition

Possible Cause

Corrective Action / Comments

 

 

 

1.5

1.5.1

ACTION 1 − Check that the unit is properly

− Diagnostic lights flash the improper

ground.

Improper ground to the unit.

ACTION 2 − Install a proper main ground to the

main ground.

unit

 

 

 

 

 

1.5.2

ACTION 1 − Check 6−pin connector for proper

 

 

LED#1−Alternating Fast Flash

6−Pin connector is improperly

installation. Correctly insert connector into con-

attached to the circuit board.

trol.

LED#2−Alternating Fast Flash

 

 

 

 

1.5.3

ACTION 1 − Check that the line voltage is above

 

Line voltage is below 75V.

75V. Determine cause of voltage drop and supply

 

correct voltage to the control.

 

 

 

 

1.5.4

ACTION 1 − Check for correct wiring and loose

 

Open ignitor circuit.

connections in the ignitor circuit. Check mult−plug

 

connections for correct installation.

 

 

 

 

1.5.5

ACTION 1 − Unplug ignitor and read resistance

 

Broken or failed ignitor.

across ignitor. If resistance does not read be-

 

tween 10.9 and 19.7 ohms, replace the ignitor.

 

 

 

PROBLEM 2: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR BLOWER DOES NOT

ENERGIZE

Condition

 

Possible Cause

Corrective Action / Comments

 

 

 

 

2.1

 

 

ACTION 1 − Check continuity across switch(es).

− Unit operates with a cooling or contin-

 

 

 

2.1.1

Switches reset automatically upon cool down.

uous fan demand.

Primary, secondary or backup secon-

ACTION 2 − Check for restrictions on blower inlet

− Combustion air inducer will not start

air (including filter) and outlet air. Determine

dary

(if equipped ) limit open.

cause for limit activation before placing unit back

with a Heating demand.

 

 

in operation.

 

 

 

−Diagnostic lights flash the limit failure mode.

 

2.1.2

ACTION 1 − Check for correct wiring and loose

 

 

LED#1−Slow Flash,

Miswiring of furnace or improper

connections. Correct wiring and/or replace any

connections at limit switch(es).

loose connections.

LED#2−On

 

 

 

 

 

 

2.2

 

 

− Unit operates with a cooling and con-

2.2.1

 

 

ACTION 1 − Check for correct wiring and loose

tinuous fan demand.

Miswiring of furnace or improper

connections. Correct wiring and/or replace any

− Combustion air inducer will not start

connections to combustion air

loose connections.

with a Heating demand.

inducer.

 

− Diagnostic lights flash the pressure

 

 

switch failure code.

 

 

2.2.2

ACTION 1 − Check that the prove switch is open

 

LED#1−Off,

Prove switch stuck closed.

without the combustion air inducer operating. Re-

place if defective.

LED#2−Slow Flash

 

 

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Contents G61MP Table of ContentsOptional Accessories − Must be Ordered Extra SpecificationsAfue Direct Vent G61MP−36B−045 Performance Less Filter Blower Data1495 2340 1285 1385 2410 G61MP Parts Arrangement Glass AssemblyTOP CAP Sight BlowerCircuit Breaker CB8 Door Interlock Switch S51−Control Box Control Transformer T1 Integrated Control Board A92Page Integrated Control Board Terminals 120VAC Neutral TWO−STAGE Integrated Control Board120VAC Line Integrated Control Board 5 Pin TerminalSecondary Limit Controls S21 −Blower Compartment Blower Motor B3 and Capacitor C4DS1 DS2 Description Supply AIR BlowerIgnitor −Heating Components Flame SensorBurners Figure Ignitor Bracket Burners Front View Burners TOP ViewCombustion Air Inducer Prove Switch S18 Flame Rollout Switches S47Clamshell Heat Exchanger Primary Limit Control S10CAI & Cold END Header BOX Assembly Dual Combustion AIR Prove SwitchFirst stage Negative Pressure Second stage Positive Combustion Air Inducer B6 Outdoor Termination Kits and Corresponding Equivalencies II−PLACEMENT and Installation−Vent Piping Guidelines Minimum Vent Pipe Lengths −PVC Joint Cementing ProcedureMaximum Vent Pipe Lengths Upflow or Downflow Direct or NON-DIRECT Vent Applications − Venting PracticesTypical Exhaust Pipe Connections From indoors and flue gases are discharged outdoors Direct Vent applications where combustion air is takenReducer Plug ReducerSweep ELL Carbon Monoxide Poisoning HazardPage − G61MP Vent Termination − AIR Inlet of Other Appliance Exhaust Pipe Termination Size Reduction Side View Front ViewG61MP Direct Vent Application Using Existing Chimney ANGLE−CUT in DirectionCondensate Piping G61MP NON−DIRECT Vent Application Using Existing ChimneySide View NON−DIRECT Vent Wall Ring Termination Vent Nipple TEE Screw Coupling CLEAN−OUT Access Condensate AssemblyHose clamp −RINGS CAP HI/LO Screws−Preliminary and Seasonal Checks For Your Safety Read Before Operating−Heating Start-Up IV−HEATING System Service Checks A−C.S.A. Certification −Safety or Emergency Shutdown−Testing Gas Piping −Extended Period Shutdown−Check Manifold Pressure −Testing Gas Supply Pressure− Proper Gas Flow Approximate − Proper Combustion− Condensate pH Range − High Altitude−Temperature Rise −Flame Signal−External Static Pressure −Blower Speed Taps VI−MAINTENANCEPage Page VII− Wiring and Sequence of Operation Sequence of Operation On Next Heating Sequence of Operation Normal Operation DS1 and DS2 Simultaneous Slow Flash YES See BOX a LOW Flame Signal YESEN or Heat Demand is SATISFIED. a Five Cooling Sequence of Operation Continuous LOW Speed FAN Sequence of Operation Single VIII− Field Wiring Applications and Jumper SettingsTWO Transformer CoolLED#2−Off Miswiring of furnace or improper con − Both diagnostic lights fail to light upDoor interlock switch failure − Diagnostic lights flash the roll−out− Diagnostic lights flash the limit failure mode Uous fan demand Primary, secondary or backup seconLED#1−Slow Flash Miswiring of furnace or improper Connections at limit switchesLED#1−Off Prove switch lines damaged Switch failure code 2.5 minutes afterCondensate in prove switch line Prove switch does not close due to aSwitch code Terminating the unit − Diagnostic lights flash the pressureWith a heating demand Installed − After 5 tries the control diagnostics− Diagnostic lights flash roll−out fail − Roll−out switch trips duringFails to stay lit Operation. Problem is characterized − Combustion air inducer energizesNostic lights flash low flame sense Burner Mode Er motorLED#1−Slow Flash Sensor rod is contaminatedService Notes

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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