Lennox International Inc G61MP specifications Testing Gas Supply Pressure, Check Manifold Pressure

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When checking piping connections for gas leaks, use pre- ferred means. Kitchen detergents can cause harmful corro- sion on various metals used in gas piping. Use of a specialty Gas Leak Detector is strongly recommended. It is available through Lennox under part number 31B2001. See Corp. 8411−L10, for further details.

Do not use matches, candles, flame or any other source of ignition to check for gas leaks.

D−Testing Gas Supply Pressure

When testing supply gas pressure, connect test gauge to inlet pressure tap on the gas valve. See figures and 35 and

36.Check gas line pressure with unit firing at maximum rate. Low pressure may result in erratic operation or under- fire. High pressure can result in permanent damage to gas valve or overfire. See table 15 for operating pressure at unit gas connection (line).

On multiple unit installations, each unit should be checked separately, with and without units operating. Supply pres- sure must fall within range listed in table 15.

TABLE 15

All G61MP Units

Natural

LP

 

 

 

Line Pressure WC"

4.5 − 10.5

11.0 − 13.0

 

 

 

E−Check Manifold Pressure

After line pressure has been checked and adjusted, check manifold pressure. Move pressure gauge to outlet pres- sure tap located on unit gas valve (GV1). Checks of man- ifold pressure are made as verification of proper regulator ad- justment. Manifold pressure for the G61MP can be measured at any time the gas valve is open and is supplying gas to the unit. See table 19 for manifold pressures.

IMPORTANT

For safety, connect a shut-off valve between the manometer and the gas tap to permit shut off of gas pressure to the manometer.

The gas valve is factory set and should not require adjust- ment. All gas valves are factory regulated sensing atmo- spheric pressure.

Manifold Pressure Measurement & Adjustment NOTE − Pressure test adapter kit (10L34) is available from Lennox to facilitate manifold pressure measurement.

1 − Connect test gauge to outlet tap on gas valve.

2 − Disconnect pressure sensing hose from gas valve.

3 − Start unit on low heat and allow 5 minutes for unit to reach steady state.

4 − While waiting for the unit to stabilize, notice the flame. Flame should be stable and should not lift from burner. Natural gas should burn blue.

5 − After allowing unit to stabilize for 5 minutes, record manifold pressure and compare to value given in table 19.

6 − Repeat steps 3, 4 and 5 on high heat.

NOTE − Shut unit off and remove manometer as soon as an accurate reading has been obtained. Take care to replace pressure tap plug.

NOTE − During this test procedure, the unit will be overfir- ing:

DOperate unit only long enough to obtain accurate read- ing to prevent overheating heat exchanger.

DAttempts to clock gas meter during this procedure will be inaccurate. Measure gas flow rate only during nor- mal unit operation.

7 − When test is complete remove obstruction from hose and return hose to gas valve barbed fitting.

F− Proper Gas Flow (Approximate)

Furnace should operate at least 5 minutes before check- ing gas flow. Determine time in seconds for two revolu- tions of gas through the meter. (Two revolutions assures a more accurate time.) Divide by two and compare to time in table 16 below. If manifold pressure matches table 15 and rate is incorrect, check gas orifices for proper size and restriction.

NOTE− To obtain accurate reading, shut off all other gas appliances connected to meter.

TABLE 16

GAS METER CLOCKING CHART

 

Seconds for One Revolution

 

 

 

 

 

 

 

G61MP

Natural

 

LP

 

Unit

1 cu ft

2 cu ft

 

1 cu ft

 

2 cu ft

 

Dial

Dial

 

Dial

 

DIAL

 

 

 

 

 

 

 

−45

82

164

 

205

 

410

 

 

 

 

 

 

 

−70

55

110

 

136

 

272

 

 

 

 

 

 

 

−90

41

82

 

102

 

204

 

 

 

 

 

 

 

−110

33

66

 

82

 

164

 

 

 

 

 

 

 

−135

27

54

 

68

 

136

 

 

 

 

 

 

 

Natural−1000 btu/cu ft

LP−2500 btu/cu ft

 

IMPORTANT

For safety, shut unit off and remove manometer as soon as an accurate reading has been obtained. Take care to replace pressure tap plug.

G− Proper Combustion

Furnace should operate minimum 15 minutes with correct manifold pressure and gas flow rate before checking com- bustion. See sections E− and F−. Take combustion sample beyond the flue outlet and compare to the tables below. The maximum carbon monoxide reading should not ex- ceed 100 ppm.

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Contents Table of Contents G61MPAfue SpecificationsOptional Accessories − Must be Ordered Extra Direct Vent Blower Data G61MP−36B−045 Performance Less Filter1495 2340 1285 1385 2410 Glass Assembly G61MP Parts ArrangementTOP CAP Sight BlowerDoor Interlock Switch S51 Circuit Breaker CB8−Control Box Control Transformer T1 Integrated Control Board A92Page TWO−STAGE Integrated Control Board Integrated Control Board Terminals 120VAC Neutral120VAC Line Integrated Control Board 5 Pin Terminal−Blower Compartment Blower Motor B3 and Capacitor C4 Secondary Limit Controls S21DS1 DS2 Description Supply AIR Blower−Heating Components Flame Sensor IgnitorBurners Figure Ignitor Bracket Burners Front View Burners TOP ViewFlame Rollout Switches S47 Combustion Air Inducer Prove Switch S18Clamshell Heat Exchanger Primary Limit Control S10First stage Negative Pressure Second stage Positive Dual Combustion AIR Prove SwitchCAI & Cold END Header BOX Assembly Combustion Air Inducer B6 II−PLACEMENT and Installation Outdoor Termination Kits and Corresponding Equivalencies−Vent Piping Guidelines Maximum Vent Pipe Lengths −PVC Joint Cementing ProcedureMinimum Vent Pipe Lengths − Venting Practices Upflow or Downflow Direct or NON-DIRECT Vent ApplicationsTypical Exhaust Pipe Connections Direct Vent applications where combustion air is taken From indoors and flue gases are discharged outdoorsReducer Plug ReducerCarbon Monoxide Poisoning Hazard Sweep ELLPage − G61MP Vent Termination − AIR Inlet of Other Appliance Exhaust Pipe Termination Size Reduction Front View Side ViewUsing Existing Chimney ANGLE−CUT in Direction G61MP Direct Vent ApplicationSide View NON−DIRECT Vent Wall Ring Termination G61MP NON−DIRECT Vent Application Using Existing ChimneyCondensate Piping Condensate Assembly Vent Nipple TEE Screw Coupling CLEAN−OUT AccessHose clamp −RINGS CAP HI/LO Screws−Heating Start-Up For Your Safety Read Before Operating−Preliminary and Seasonal Checks −Safety or Emergency Shutdown IV−HEATING System Service Checks A−C.S.A. Certification−Testing Gas Piping −Extended Period Shutdown−Testing Gas Supply Pressure −Check Manifold Pressure− Proper Gas Flow Approximate − Proper Combustion− High Altitude − Condensate pH Range−External Static Pressure −Flame Signal−Temperature Rise VI−MAINTENANCE −Blower Speed TapsPage Page VII− Wiring and Sequence of Operation Sequence of Operation On Next Heating Sequence of Operation See BOX a LOW Flame Signal YES Normal Operation DS1 and DS2 Simultaneous Slow Flash YESEN or Heat Demand is SATISFIED. a Five Cooling Sequence of Operation Continuous LOW Speed FAN Sequence of Operation TWO VIII− Field Wiring Applications and Jumper SettingsSingle Cool Transformer− Both diagnostic lights fail to light up LED#2−Off Miswiring of furnace or improper conDoor interlock switch failure − Diagnostic lights flash the roll−outUous fan demand Primary, secondary or backup secon − Diagnostic lights flash the limit failure modeLED#1−Slow Flash Miswiring of furnace or improper Connections at limit switchesSwitch failure code 2.5 minutes after LED#1−Off Prove switch lines damagedCondensate in prove switch line Prove switch does not close due to aTerminating the unit − Diagnostic lights flash the pressure Switch codeWith a heating demand Installed − After 5 tries the control diagnostics− Roll−out switch trips during − Diagnostic lights flash roll−out failFails to stay lit Operation. Problem is characterized − Combustion air inducer energizesMode Er motor Nostic lights flash low flame sense BurnerLED#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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