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Page 15

 3 - Turn off all electrical power to the unit.

 4 - This furnace is equipped with an ignition device which

automatically lights the burners. Do 

not

 try to light the

burners by hand.

 5 - Remove the upper access panel.

 6 - Turn switch on gas valve to 

OFF

. Do not force. See

figure 11.

 7 - Wait five minutes to clear out any gas. If you then smell

gas, STOP! Immediately call your gas supplier from a
neighbor's phone. Follow the gas supplier's instruc­
tions. If you do not smell gas go to next step.

GAS VALVE SHOWN IN ON POSITION

INLET PRESSURE POST

HIGH FIRE ADJUSTMENT

SCREW

(under cap)

MANIFOLD

PRESSURE TAP

WHITE RODGERS GAS VALVE

FIGURE 11

LOW FIRE ADJUSTMENT

SCREW

(under cap)

 8 - Turn switch on gas valve to 

ON

. Do not force. See fig­

ure 11.

 9 - Replace the upper access panel.

10- Turn on all electrical power to to the unit.

11- Set the thermostat to desired setting.

NOTE - When unit is initially started, steps 1 through 11
may need to be repeated to purge air from gas line.

Turning Off Gas To Unit

 1 - Set thermostat to lowest setting.
 2 - Turn off all electrical power to unit if service is to be per­

formed.

 3 - Remove access panel.

 4 - Turn switch on gas valve to  

OFF

. Do not force. See fig­

ure 11.

 5 - Replace 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 -Are flame rollout switches tripped? If flame rollout

switches are tripped, call the service technician for in­
spection.

C-Safety or Emergency Shutdown

Turn off  unit power. Close manual and main gas valves.

D-Extended Period Shutdown

Turn off thermostat or set to “UNOCCUPIED” mode. Close
all gas valves (both internal and external to unit) to guaran­
tee no gas leak into combustion chamber. Turn off power to
unit. All access panels and covers must be in place and se­
cured.

Summary of Contents for EL280DF SERIES

Page 1: ...nual except where noted are recommendations only and do not consti tute code TABLE OF CONTENTS Specifications Page 2 Blower Performance Data Page 3 Parts Identification Page 4 I Unit Components Page 5...

Page 2: ...2 x 10 Motor output hp 1 3 1 2 1 Tons of add on cooling 2 3 5 3 4 4 5 Air Volume Range cfm 717 1562 917 1929 1517 2760 Electrical Data Voltage 120 volts 60 hertz 1 phase Blower motor full load amps 6...

Page 3: ...1585 572 1332 489 0 20 1864 717 1745 623 1544 540 1321 463 0 30 1779 683 1676 588 1496 510 1296 440 0 40 1694 647 1600 558 1443 473 1265 417 0 50 1596 607 1502 511 1363 440 1212 393 0 60 1483 577 141...

Page 4: ...ION Control Box includes integrated control transformer and door switch Secondary Limit Internal Flue Pipe Assembly Gas Val ve Burner Box Assembly Combustion Air Inducer Indoor Blower Heat Exchanger P...

Page 5: ...pted 4 SureLight Integrated Control A92 EL280DF units are equipped with the Lennox two stage in tegrated SureLight control The system consists of a igni tion blower control figures 5 and 6 with contro...

Page 6: ...eration flow charts in the back of this manual for more detail DIP Switch Settings Switch 1 Thermostat Selection This unit may be used with either a single stage or two stage thermostat The thermostat...

Page 7: ...ool ing only TWO STAGE INTEGRATED CONTROL THERMOSTAT CONNECTIONS TB1 1 4 QUICK CONNECT TERMINALS DIP SWITCH FUNCTIONS DIP SWITCHES DIAGNOSTIC LEDs ON BOARD LINKS 1 ERROR CODE RECALL H 24V HUMIDIFIER O...

Page 8: ...Page 8 INTEGRATED CONTROL FIGURE 6...

Page 9: ...5 1 Hard lockout Rollout circuit open or previously opened 5 2 Control failed self check internal error control will restart if error recovers 5 3 No Earth ground control will restart if error recove...

Page 10: ...as Valve The two stage gas valve figure 11 is internally redundant to assure safety shut off If the gas valve must be replaced the same type valve must be used 24VAC terminals and ON OFF switch are lo...

Page 11: ...Page 11 EL280DF HEATING COMPONENTS FIGURE 7 Ignitor Burners Sensor Gas Valve Manifold and Gas Orifices Rollout Switch...

Page 12: ...t damage plug Check voltage during 20 second ignitor warm up period Voltage should read 120 volts or 10 If voltage is above or below these values check for correct supply voltage to furnace Test 1 Che...

Page 13: ...thermostat contacts to cycle system 7 When main burners are in operation for two minutes take reading TABLE 5 Flame Signal in Microamps Normal Low Drop Out 1 9 or greater 1 4 or less 20 FIGURE 9 Measu...

Page 14: ...f the combus tion air inducer is not operating or if the flue becomes ob structed On heat demand first or second stage the switch senses that the combustion air inducer is operating It closes a cir cu...

Page 15: ...ove access panel 4 Turn switch on gas valve to OFF Do not force See fig ure 11 5 Replace access panel Failure To Operate If the unit fails to operate check the following 1 Is the thermostat calling fo...

Page 16: ...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...

Page 17: ...re adjustment or replacement to ensure proper operation at higher altitudes See table 10 for manifold pressures and table 11 for pressure switch kits and gas conversion kits TABLE 10 Manifold Pressure...

Page 18: ...E 13 Return Supply TEMPERATURE RISE Supply Duct Temperature Return Duct Temperature _ Temperature Rise C External Static Pressure 1 Tap locations shown in figure 14 2 Punch a 1 4 diameter hole in supp...

Page 19: ...and unobstructed to provide combustion air 10 Inspect the furnace venting system to make sure it is in place structurally sound and without holes corrosion or blockage Vent system must be free and cl...

Page 20: ...e careful with the collector box gas ket If the gasket is damaged it must be replaced to prevent leakage 6 Disconnect gas supply piping Remove the screw se curing the burner box cover and remove cover...

Page 21: ...bustion air inducer Failure to replace all screws may cause leaks Inspect gaskets for any damage and replace if necessary 15 Reinstall burner box manifold assembly and burner box cover 16 Reconnect al...

Page 22: ...Page 22 VII Wiring and Sequence of Operation EL280DF Schematic Wiring Diagram...

Page 23: ...first stage de mand is satisfied 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...

Page 24: ...DIP Switch 1 W915 Two Stage Cooling W951 Heat Pumps 1 Heat 1 Cool NOTE Use DIP switch 2 to set sec ond stage heat ON delay OFF10 minutes ON 15 minutes ON Intact Intact S1 T STAT CONTROL TERM STRIP OU...

Page 25: ...P Switch Settings and On Board Links See figure 6 Wiring Connections DIP Switch 1 W915 Two Stage Cooling W951 Heat Pumps 2 Heat 2 Cool OFF Cut Intact S1 T STAT CONTROL TERM STRIP OUTDOOR UNIT 2 Heat 1...

Page 26: ...OR T STAT IS CYCLED OFF ON FOR 3 SEC MINIMUM NO YES FIRST LOW STAGE PRESSURE SWITCH CONTACTS OPEN NO GAS VALVE OFF COMBUSTION AIR INDUCER OFF INDOOR BLOWER OFF CONTROL REMAINS UNTIL PRESSURE SWITCH I...

Page 27: ...NDS AFTER GAS VALVE OPENS u0 19 microamps GAS VALVE OFF COMBUSTION AIR INDUCER ON INDOOR BLOWER OFF STATUS LED HEARTBEAT HAS CONTROL FAILED TO SENSE FLAME FOR FIVE CONSECUTIVE TRIES DURING A SINGLE HE...

Page 28: ...ST STAGE HEAT DEMAND SATISFIED GAS VALVE OFF COMBUSTION AIR INDUCER OFF FOLLOWING POST PURGE INDOOR BLOWER OFF WITH DELAY STATUS LED PULSE YES SECOND STAGE HEAT DEMAND SECOND STAGE HEAT DEMAND REQUIRE...

Page 29: ...ODE DIP SWITCH SET AT SINGLE YES YES FIRST AND SECOND STAGE HEAT DEMAND SATISFIED SIMULTANEOUSLY STATUS LED HEARTBEAT YES GAS VALVE OFF COMBUSTION AIR INDUCER OFF AFTER 5 SECOND LOW SPEED POST PURGE P...

Page 30: ...ZED NO IS THERE PROPER GROUND YES NO INDOOR BLOWER ENERGIZED ON FIRST STAGE COOL SPEED AFTER 2 SECOND DELAY FIRST STAGE DEMAND FOR COOL SATISFIED NO THERMOSTAT CALLS FOR SECOND STAGE COOL COMPRESSOR A...

Page 31: ...TO LOW HEAT SPEED FIRST STAGE HEAT DEMAND SATISFIED YES NO THERMOSTAT CALLS FOR SECOND STAGE HEAT YES INDOOR BLOWER SWITCHES TO HIGH HEAT SPEED AFTER 30 SECOND RECOGNITION PERIOD SECOND STAGE HEAT DE...

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