Lennox International Inc G61MP specifications Sequence of Operation

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Sequence of Operation

Sequence depends on type thermostat used. G61MP units are applicable for single stage or two stage ther- mostats. Both type thermostats are described below. Thermostat jumper E20 dictates which mode unit will operate in. See flow chart for more sequence detail.

SureLight Control Self Check

When there is a call for heat, the SureLight integrated con- trol runs a self check. The control checks for S10 primary limit, S21 secondary limit (s) and S47 rollout switch nor- mally closed contacts. The control also checks for S102 high heat and S128 low heat prove switch normally open contacts. Once self check is complete and all safety switches are operational, heat call can continue.

Two−Stage Thermostat, Two Stage Heat. Jumper E20

set at

1− SureLight control energizes combustion air inducer B6 on low heat speed. Combustion air inducer runs until S128 low heat prove switch contacts close (switch must close within 2 1/2 minutes or control goes into Watchguard Pressure Switch mode. High heat prove switch S102 may also close). A 15 second pre−purge follows once S128 closes.

2− SureLight control begins 20 second ignitor warm up period.

3− Gas valve opens on first stage for a 4 second trial for ignition. Ignitor stays energized during the trial or until flame sensed.

4− Flame is sensed, gas valve remains on first stage heat, ignitor de−energizes.

5− After 45 second delay, indoor blower B3 is energized on low heat speed.

The furnace will stay in this mode until first stage de- mand is satified OR a second stage heat demand is initiated.

6− Second stage heat demand initiated. A 30 second sec- ond stage recognition period begins.

7− The combustion air inducer ramps up to high heat speed.

8− S102 high heat prove switch closes and the gas valve energizes second stage heat.

9− B3 indoor blower energizes on high heat speed.

Single−Stage Thermostat, Two Stage Heat. Jumper E20 set at SINGLE"

1− SureLight control energizes combustion air inducer B6 on low heat speed. Combustion air inducer runs until S128 low heat prove switch contacts close (switch must close within 2 1/2 minutes or control goes into Watchguard Pressure Switch mode High heat prove switch S102 may also close). A 15 second pre−purge follows once S128 closes.

2− SureLight control begins 20 second ignitor warm up period.

3− Gas valve opens on first stage for a 4 second trial for ignition. Ignitor stays energized during the trial or until flame sensed.

4− Flame is sensed, gas valve remains on first stage heat, ignitor de−energizes.

5− After 45 second delay, indoor blower B3 is energized on low heat speed.

6− A 10 minute (factory set) or 15 minute (field set) second stage heat delay period begins.

7− After the delay the combustion air inducer ramps up to high heat speed.

8− S102 high heat prove switch closes and the gas valve energizes second stage heat.

9− B3 indoor blower energizes on high heat speed.

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Contents G61MP Table of ContentsSpecifications Optional Accessories − Must be Ordered ExtraAfue Direct Vent G61MP−36B−045 Performance Less Filter Blower Data1495 2340 1285 1385 2410 Sight Blower Glass AssemblyG61MP Parts Arrangement TOP CAPIntegrated Control Board A92 Door Interlock Switch S51Circuit Breaker CB8 −Control Box Control Transformer T1Page Integrated Control Board 5 Pin Terminal TWO−STAGE Integrated Control BoardIntegrated Control Board Terminals 120VAC Neutral 120VAC LineSupply AIR Blower −Blower Compartment Blower Motor B3 and Capacitor C4Secondary Limit Controls S21 DS1 DS2 DescriptionIgnitor Bracket Burners Front View Burners TOP View −Heating Components Flame SensorIgnitor Burners FigurePrimary Limit Control S10 Flame Rollout Switches S47Combustion Air Inducer Prove Switch S18 Clamshell Heat ExchangerDual Combustion AIR Prove Switch CAI & Cold END Header BOX AssemblyFirst stage Negative Pressure Second stage Positive Combustion Air Inducer B6 Outdoor Termination Kits and Corresponding Equivalencies II−PLACEMENT and Installation−Vent Piping Guidelines −PVC Joint Cementing Procedure Minimum Vent Pipe LengthsMaximum Vent Pipe Lengths Upflow or Downflow Direct or NON-DIRECT Vent Applications − Venting PracticesTypical Exhaust Pipe Connections Reducer Direct Vent applications where combustion air is takenFrom indoors and flue gases are discharged outdoors Reducer PlugSweep 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 DirectionG61MP NON−DIRECT Vent Application Using Existing Chimney Condensate PipingSide View NON−DIRECT Vent Wall Ring Termination −RINGS CAP HI/LO Screws Condensate AssemblyVent Nipple TEE Screw Coupling CLEAN−OUT Access Hose clampFor Your Safety Read Before Operating −Preliminary and Seasonal Checks−Heating Start-Up −Extended Period Shutdown −Safety or Emergency ShutdownIV−HEATING System Service Checks A−C.S.A. Certification −Testing Gas Piping− Proper Combustion −Testing Gas Supply Pressure−Check Manifold Pressure − Proper Gas Flow Approximate− Condensate pH Range − High Altitude−Flame Signal −Temperature Rise−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 VIII− Field Wiring Applications and Jumper Settings SingleTWO Transformer Cool− Diagnostic lights flash the roll−out − Both diagnostic lights fail to light upLED#2−Off Miswiring of furnace or improper con Door interlock switch failureConnections at limit switches Uous fan demand Primary, secondary or backup secon− Diagnostic lights flash the limit failure mode LED#1−Slow Flash Miswiring of furnace or improperProve switch does not close due to a Switch failure code 2.5 minutes afterLED#1−Off Prove switch lines damaged Condensate in prove switch line− After 5 tries the control diagnostics Terminating the unit − Diagnostic lights flash the pressureSwitch code With a heating demand Installed− Combustion air inducer energizes − Roll−out switch trips during− Diagnostic lights flash roll−out fail Fails to stay lit Operation. Problem is characterizedSensor rod is contaminated Mode Er motorNostic lights flash low flame sense Burner LED#1−Slow FlashService 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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