7313 William Barry Blvd.
North Syracuse, NY 13212
ICM CONTROLS 800.365.5525
www.icmcontrols.com LIAF098
FEATURES
• DirectSparkIgnition(DSI)controlboard
• Microprocessor-based
• Controlscombustion,blowerandindoormotors;sparkignitor;andthegasvalve
• Monitorstiming,trialforignition,amesensingandlockout
• 100%lockoutsafetyfeature
• CompatiblewithLPorNaturalGas
• StatusLEDforfaultcodestoaidintroubleshooting
• Replaces:CarrierLH33WP003A
Install New Control
1. Groundyourself.Whenhandlingcircuitboard,holditbytheedges.
2. Fastencircuitboardwithretainingscrews.
3. Connectalllinevoltage,lowvoltage,andaccessorywires.
4. Verifythesequenceofoperation.
Safety Considerations
Onlytrainedpersonnelshouldinstallorserviceheatingequipment.Whenworkingwithheating
equipment,besuretoreadandunderstandallprecautionsinthedocumentation,onlabels,andon
tagsthataccompanytheequipment.Failuretofollowallsafetyguidelinesmayresultindamageto
equipment,severepersonalinjuryordeath.
Introduction
TheICM291DSIgasignitioncontrolreplacesthefollowingCarriermodel:LH33WP003A.The
ICM291hasincorporatedLEDdiagnosticstoassistintroubleshooting.Faultcodeinformationcanbe
foundinthisapplicationguide.Pleasekeepthisapplicationguidewiththefurnaceinstallationmanual
forfuturereference.
Electrostatic Discharge (ESD) Precautions
CAUTION!
Use caution when installing and servicing the furnace to avoid and control electrostatic discharge;
ESD can impact electronic components. These precautions must be followed to prevent
electrostatic discharge from hand tools and personnel. Following the precautions will protect the
control from ESD by discharging static electricity buildup to ground.
1. Disconnectallpowertothefurnace.Donottouchthecontrolorthewiringpriortodischargingyour
body’selectrostaticchargetoground.
2. Togroundyourself,touchyourhandandtoolstoaclean,metal(unpainted)furnacesurfacenear
thecontrolboard.
3. Servicethefurnaceaftertouchingthechassis.Yourbodywillrechargewithstaticelectricityasyou
shufeyourfeetormovearound,andyoumustregroundyourself.
4. Regroundyourselfifyoutouchungroundeditems.
5. Beforehandlinganewcontrol,regroundyourself;thiswillprotectthecontrol.Storeusedandnew
controlsinseparatecontainersbeforetouchingungroundedobjects.
6. ESDdamagecanalsobepreventedbyusinganESDservicekit.
CAUTION!
To service control, and prior to disconnection, label all wires. Failure to do so may result in wiring
errors that can cause dangerous operation.
1. TurnthermostattoOFFpositionorsetittothelowestpossiblesetting.
2. TurnOFFelectricalsupplytofurnace.
3. TurnOFFgassupplytofurnace.
CAUTION:Failuretoturnoffgasandelectricsuppliescanresultinexplosion,re,death,or
personalinjury.
4. Removefurnaceblowerandcontrolaccessdoors.
5. Disconnectthermostatwiresandhumidierwires(ifequippedwithahumidier).
6. Disconnectlinevoltage,blower,electronicaircleanerwires(ifequipped),andtransformerwires.
7. Removescrewsandanyotherfasteners,andtheoldcircuitboard.
8. Examinecontrolandcontrolboxtocheckforwaterstains.
9. Makerepairsifanysourcesofwaterleakagearefound.Besuretocheckhumidiers,evaporator
coils,andventsystemsintheareaofthecontrol.
Remove Existing Control
SPECIFICATIONS
• Controlvoltage:24VAC(18-30VAC),60Hz
• Linevoltage:208/230VAC,60Hz
• Powerconsumption: 0.3Aplusgasvalvecurrentat24VAC
• OperatingTemperature: -40°C(-40°F)to75°C(176°F)
Timing
• Pre-purge:45seconds
• TrialforIgnition:5+2seconds
• Retryperiod:every20sec.for15min.
• Lockout:manualreset
• Post-purge:45seconds
Inputs
• Power:RTandC
• Thermostatinterface:R,WandG
• Safetyswitches:RS,LS,andCS
• CombustionmotorHallEffectsensor
• FlameSensing
Outputs
• Spark
• GasValve:GV
• Combustionmotor:CM
• Blowermotor:BM
• Indoorfanmotor:IFO
LEDindicators
• RedLED: SteadyON-normaloperation
Flashing-faultcodes
ICM291
Gas Ignition Control Board
AWcallfromtheT’statwillengagethecombustionmotor.Ignitionsequencebegins,gasvalveand
sparkareengaged,providingthatsystemsafetyswitches(RS,LS,andCS)areclosedandthereis
feedbackfromthecombustionmotorHallEffectsensor.Theblowerandindoormotorswillengage45
secondsafterameisestablishedandsensed.Theydisengage45secondsafterWcallissatised.
AGcallfromtheT’statwillengageblowerandindoormotorsrightaway.Theydisengage25seconds
afterGcallisremoved.
Sequence of Operation
Flamenotestablished
1. Ifameisnotestablishedduringthe5+2initialsequencethenthecontrolwillstartthenexttrialfor
ignitionin20seconds.
2. Theattempttoignitewillcontinuefor15minutesbeforetherespectivefaultcodeistriggeredand
ignitiontrialsarestopped.
3.Thegasvalveisenergizedonlyduringtheignitionsequenceof5+2seconds.
4. Blowerandindoorfanmotorsareoffuntilameisestablishedand45secondslater.
Flameout
1. Flameoutisconsideredwhenameislostduringheating.
2. WhenWsignalispresentandameissensedoutthenthesparkwillstartrightaway.
3. Ifameisnotestablishedontheimmediatesequence(2above)thenthecontrolwillcontinue
attemptsevery20secondsfor15minutesbeforetherespectivefaultcodeistriggeredandignition
trialsarestopped.
4. Blowerandindoorfanmotorswillcontinuerunningduringameoutscenariofor15minutes+45
seconds.
5.Combustionmotorremainsonthroughouttheameoutscenario.
Flameoutofsequence
1. FlameoutofsequencerepresentsascenariowhenameissensedwhileWsignalisnotpresent.
2. Combustion,blowerandindoorfanmotorswillbeengaged(ifnotalreadyrunning)rightawayand
keeprunningforaslongasthefaultconditionispresent.
3. Theunitisoperablebutwilldisplaythefaultcodeconstantlyuntilreplacedbyanotherfaultcodeor
powerreset.
NosignalfromtheHallaffectsensor
1. OnaWcall,iftheinputfromtheHallaffectsensor(RA0)isnotpresentformorethanaminute,
thenthecombustionmotorwillcontinuerunningendlesslyandtherespectivefaultisashed.
2. DuringrunningstateiftheinputfromtheHallaffectsensorisnotsensedthenthegasvalvewill
shutoffrightaway,blowerandindoorfanmotorswillcontinuerunningfor30secondsandthen
turnoff,combustionmotorrunscontinuously.
Troubleshooting Tips
LED Fault Codes
#OfFlashes
representsConstant
ONNormal
operation
Results
1Thecontrolhasmodiedthefanondelayto0andoffdelayto3minutes
duetosensingLStripwithin10minutesofacall
2a) LSisopenduetohightemperature(fanisn’tworkingscenario)
b) Theunitwillnotstartatrialforignitionuntiltheswitchclosesback
3
a) Flamesensedoutofsequence.
b) Theunitisoperable,howeverwilldisplaythisfaultcodeuntilpower
resetoranothercode
4a) LSopened4consecutivetimesduringacallforheating
b) ThefaultcodeisresetonthenextWcall
5a) Ignitionlockout.Thecontroltriedunsuccessfullytoignitefor15minutes
b) Theunitwillnotoperate.Requirespowerreset
6a) ThecombustionmotorisnotsensedrunningORCSopen
b) Theunitwillnotoperate.Requirespowerreset
7a) RStripped
b) Theunitwillnotoperate.Requirespowerreset
8a) Internalcontrolfault(softwareselfcheck)
