Lennox International Inc SL280DFV Gas Pressure Adjustment, Proper Combustion

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12− If the appliance will not operate, follow the instructions urning Off Gas to Unit" and call your service techni- cian or gas supplier.

Turning Off Gas to Unit

1 − Set the thermostat to the lowest setting.

2 − Turn off all electrical power to the unit if service is to be performed.

3 − Remove the upper access panel.

4 − Move switch on gas valve to OF. Do not force. See fig- ure 26 or 27.

5 − Replace the upper access panel. Failure To Operate

If the unit fails to operate, check the following:

1 − Is the thermostat calling for heat?

2 − Are access panels securely in place?

3 − Is the main disconnect switch closed?

4 − Is there a blown fuse or tripped circuit breaker?

5 − Is the filter dirty or plugged? Dirty or plugged filters will cause the limit control to shut the unit off.

6 − Is gas turned on at the meter?

7 − Is the manual main shut-off valve open?

8 − Is the internal manual shut-off valve open?

9 − Is the unit ignition system in lock out? If the unit locks out again, call the service technician to inspect the unit for blockages.

10 −Is pressure switch closed? Obstructed flue will cause unit to shut off at pressure switch. Check flue and outlet for blockages.

11 − Is the rollout switch tripped? If the switch is tripped call the service technician to inspect the unit.

Gas Pressure Adjustment

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 22 below. If manifold pressure matches table 24 and rate is incorrect, check gas orifices for proper size and restriction. Remove temporary gas meter if installed.

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

TABLE 22

GAS METER CLOCKING CHART

 

 

Seconds for One Revolution

 

 

 

 

 

 

 

 

SL280

 

Natural

 

LP

 

Unit

 

1 cu ft

2 cu ft

 

1 cu ft

 

2 cu ft

 

 

Dial

Dial

 

Dial

 

DIAL

 

 

 

 

 

 

 

 

−045

 

80

160

 

200

 

400

 

 

 

 

 

 

 

 

−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

 

Supply Line Pressure

White Rodgers Gas Valve

An inlet post located on the gas valve provides access to the supply pressure. See figure 27. Back out the 3/32 hex screw one turn, connect a piece of 5/16 tubing and connect to a manometer to measure supply pressure. See table 24 for supply line pressure.

Honeywell Gas Valve

A threaded plug on the inlet side of the gas valve provides access to the supply pressure tap. Remove the threaded plug, install a field−provided barbed fitting and connect a manometer to measure supply pressure. See table 24 for supply line pressure. Replace the threaded plug after mea- surements have been taken.

Manifold Pressure

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

1 − Connect test gauge to manifold pressure post (figure 26) or tap (figure 27) on gas valve.

2 − Ignite unit on high fire and let run for 5 minutes to allow for steady state conditions.

3 − After allowing unit to stabilize for 5 minutes, record manifold pressure and compare to value given in table 24.

4 − If necessary, make adjustments. Figures 26 and 27 show location of high fire adjustment screw.

5 − If an adjustment is made on high fire, re−check man- ifold pressure on low fire. Do not adjust low fire man- ifold pressure. If low fire manifold pressure is more than 1/2" above or below value specified in table 24, replace valve.

Proper Combustion

Furnace should operate minimum 15 minutes with correct manifold pressure and gas flow rate before checking com- bustion. Table 23 shows acceptable combustion for ALL SL280DFV models.

TABLE 23

Firing Rate

CO2% For Nat

CO2% For L.P.

High Fire

6.0 − 7.4

6.9 − 8.4

 

 

 

Low Fire

4.8 − 6.0

5.7 − 7.0

 

 

 

The carbon monoxide reading should not exceed 50 ppm.

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Contents Installation Instructions SL280DFV Table of ContentsUnit Dimensions − inches mm TOP ViewParts Arrangement SL280DFV Gas Furnace Safety InformationShipping and Packing List Use of Furnace as Construction Heater GeneralCombustion, Dilution & Ventilation Air Equipment in Confined Space ALL AIR from Inside Equipment in Confined Space Equipment in Confined Space ALL AIR from OutsideEquipment Confined Space ALL AIR from Outside Downflow Installation NON−COMBUSTIBLE Floor Opening SizeSetting Equipment SL280DFV UnitCooling Coil Properly Plenum Sized Floor OpeningFilters Duct System VentingTables for installations −1/2 MIN MAX 126 FAN + FAN FAN + NAT 168 Gas Piping Carbon Monoxide Poisoning HazardGas Pipe Capacity − ft3/hr m3/hr Electrical MAKE−UP BOXNon−Communicating Icomfortt Integrated Control Outdoor Unit Icomfort Touch System Wiring 120V ConnectionsApplications 24V Humidifier ConnectionsSL280 Field Wiring Applications With Conventional Thermostat OFF Single Stage Thermostat w Dual fuel capa Bilities SL280DFV Schematic Wiring Diagram Typical SL280DFV Field Wiring Diagram Integrated Control + = Data High Connection − = Data LOW Connection−10% approx OFF On−Board Links Blower Data 1400 Operating System Demand System Response Sequence VAC Room Thermostat Calls for First Stage Cooling Unit Start−Up GAS Valve Shown in on PositionGas Pressure Adjustment Proper CombustionManifold Pressure Settings High AltitudeOther Unit Adjustments Heating Sequence of OperationHeating Operation with TWO−STAGE Thermostat SECService Electrical SHOCK, Fire Or Explosion HazardSL280DFV BURNER, Combustion AIR Inducer Assembly Page Planned Service Repair Parts ListIntegrated Control Diagnostic Modes Integrated Control Diagnostic CodesEquipment is unable to communicate. Indicates Reconfigure the system. Replace control if heating Low pressure switch failed open To flame failure Limiters to protect the motor from damage caused Sor run cycle, or after power reset Program Unit Capacity/Size Mode Volt power−up of the furnace control,Troubleshooting Heating Sequence of Operation Call for FIRST−STAGE HeatCall for SECOND−STAGE Heat Call for Heat SatisfiedCall for Heat Satisfied FIRST−STAGE Heat SECOND−STAGE Heat 2ND Stage HeatTroubleshooting Cooling Sequence of Operation Call for CoolingTroubleshooting Continuous Fan Sequence of Operation Call for FAN
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DAVE LENNOX SIGNATURE COLLECTION GAS FURNACE, SL280DFV specifications

Lennox International Inc has made a significant mark in the heating, ventilation, and air conditioning (HVAC) industry, known for its commitment to innovation and energy efficiency. One of its standout products is the SL280DFV model, a high-efficiency gas furnace designed to meet the needs of modern homes.

The SL280DFV boasts an impressive Annual Fuel Utilization Efficiency (AFUE) rating of up to 80%. This rating indicates that the furnace converts 80% of the fuel it consumes into usable heat, making it a cost-effective choice for homeowners. The high efficiency not only reduces energy bills but also lessens the environmental impact by minimizing greenhouse gas emissions.

One of the key features of the SL280DFV is its two-stage gas valve operation. This technology allows the furnace to operate at two levels of heating output: low stage for milder days and high stage for extremely cold temperatures. This adaptability enhances comfort by maintaining more consistent indoor temperatures while also saving energy when full power is unnecessary.

Another innovative aspect of the SL280DFV is its variable-speed blower motor. This smart technology enables the furnace to adjust airflow based on the heating needs of a home, which promotes quiet operation and improved temperature consistency throughout living spaces.

The SL280DFV is equipped with a durable heat exchanger that is designed to withstand the rigors of daily use, contributing to the unit’s longevity. Additionally, the furnace features a smart ignition system that ensures reliable start-ups, so homeowners can depend on it through the coldest winter nights.

Safety is also a priority in the design of the SL280DFV. It includes various safety features such as a built-in flame sensor and advanced venting system, designed to avert hazardous situations and ensure optimal operation.

Furthermore, Lennox offers convenient installation and maintenance support, making the SL280DFV not only an efficient heating solution but also a practical choice for homeowners. With its blend of advanced technology, high efficiency, and reliability, the Lennox SL280DFV is an appealing option for those looking to upgrade their home’s heating system, promising comfort and peace of mind for many winters to come.