A.O. Smith 110 User manual

TroubleshootingGuide
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Non‐CondensingModels
On‐DemandWaterHeater
TroubleshootingGuide
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110Indoor(T‐KJr2‐IN)   110Outdoor(T‐KJr2‐OS)
310Indoor(T‐K4‐IN)310Outdoor(T‐K4‐OS)
510Indoor(T‐D2‐IN)510Outdoor(T‐D2‐OS)
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9/12/11321923‐000
A.O. SmithWaterProductsCompany
500TennesseeWaltzParkway
AshlandCity,TN37015
TollFree:1‐877‐737‐2840
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html
AO Smith general troubleshoot guide

TroubleshootingGuide
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TableofContents
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1. SPECIFICATIONS.……………………………………………………………………………..……………………3
2. INTRODUCTION.…………………………………………………………………………………..………………4
3. NORMALOPERATION…………….………………………………………………………………………..…..5
Activation………………………………………………………………………………………………….5
Operation..………………………………………………………………………………………………..5
Shutdown……….………….………….……………………………………………………………..…..5
4. INSTALLATION….…………………………………………………………………………….…………………….6
Venting…………….………………………………………………………………………………..…..…6
GasLine…………….………………………………………………………………………………………6
WaterLine……………………..…….……………………………………………………………..…..6
PowerSupply..…………………………………………………………………………………………..6
5. TROUBLESHOOTING....…………………………………………………………………………………………7
PreliminaryChecklist.………………………………………………………………………..…..…7
GeneralProblems..……………………………………………………………………………………8
ErrorCodes.………………………….……………………………………………………………..….12
Procedures.……..……………………………………………………………………………………….19
VerifyingproperDipswitchsettings...……………………..………………….…19
Drainingtheunit...…………………………………………………………………………21
Cleaningthefilter..………………………………………….…………………………….21
CheckingforaCrossConnection..………………………………………….………21
CheckforReverseConnection..………………………………………….………….21
Checkgassupplypressure……..…………………………………….……………….21
Purgethegaslineofair…………..……………………………….…………………..22
Adjustingmanifoldpressure……..…………………………………….…………….22
Resettingthecomputerboard……..…………………………………….…………23
CheckingtheOHCF………………………..….………………………………………….24
6. MAINTENANCE….…..……………………………………………….……………………………………….……25
RodAssembly..…………………………………………………………………………………..…..…25
Burner&RodAssembly…..………………………………………………………………………..26
HeatExchanger…..….…………….……………………………………………………………..…..29
FlowSensor….….………………………………………………………………………………………..31
DescalingtheUnit……………………………………………………………………………………..32
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TroubleshootingGuide

TroubleshootingGuide
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1.SPECIFICATIONS
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Table1

TroubleshootingGuide
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2.INTRODUCTION
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Thismanualprovidesthenecessaryinformationfortroubleshootingthe110(T‐KJr2),310(T‐K4),510(T‐
D2)tanklesswaterheaters.Itwillbeeffectiveinhelpingyourtroubleshootingneedsaslongasthe
instructionsarefollowedintheintendedorder.Hereishowtousethismanual:
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•FirstrefertotheInstallationManualastheprimarysourceofinformation.Refertoitalongside
thismanualthroughoutthetroubleshootingprocess.
•Beforetroubleshooting,ifyouareunfamiliarwithhowatanklessunitoperates,readtheNormal
Operationsection(p.5).
•Todouble‐check/troubleshootanewinstallation,usetheProperInstallationsection(p.6).
•Whenbeginningtroubleshooting,firstgothroughthePreliminaryChecklist(p.7);itisdesigned
tofixthemostcommonandfrequentproblems,andprovideyouwithbackgroundinformation
tohelpnarrowdowntheinformationyouneed.
•AfterthePreliminaryChecklist,movetotheErrorCodessection(p.12)ifyouhavereceivedan
errorcode,ortoGeneralProblems(p.8)ifyouhavenotreceivedanerrorcode.
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Ifyouhaveanyproblemsorquestionsregardingthisequipment,oratanypointbecomeconfusedor
uncomfortablewithanyoftheprocedures,consultwiththetechnicalservicedepartmentorservice
agent.
IMPORTANT
•Installationandservicemustbeperformedbyaqualifiedinstaller(for
example,alicensedplumberorgasfitter).Otherwisethewarrantywill
bevoid.
•Theinstaller/serviceagent(licensedprofessional)isresponsiblefor
correctlyinstallingorservicingyourwaterheaterandforcompliance
withallnational,state/provincial,andlocalcodes.
*ForallunitsinstalledinthestateofMassachusetts,itisrequiredthattheinstallereitherbea
licensedplumberorlicensedgasfitter.
GENERALINSTALLATIONGUIDELINES
1. Followalllocalcodes,orintheabsenceoflocalcodes,followthemostrecenteditionofthe
NationalFuelGasCode:ANSIZ223.1/NFPA54intheUSAorCAN/CSAB149.1NaturalGas,Propane
InstallationCodeinCanada.
2. Properlygroundtheunitinaccordancewithalllocalcodesorintheabsenceoflocalcodes,with
theNationalElectricalCodes:ANSI/NFPA70intheUSAorCSAstandardC22.1CanadaElectrical
CodePart1inCanada.
3. Carefullyplanwhereyouintendtoinstallyourwaterheater.
4. ChecktheratingplateforthecorrectGASTYPE,GASPRESSURE,WATER
PRESSUREandELECTRICRATING.
*Ifthisunitdoesnotmatchyourrequirements,donotinstall.
5. Ifanyproblemshouldoccur,turnoffallhotwatertapsandturnoffthe
gas.Thencallatrainedtechnicianorthegascompany.
WARNING
RATING
PLATE
Figure1

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3.NORMALOPERATION
Becomingfamiliarwithhowatanklesswaterheaternormally
operatesmayhelptofigureoutwhatiswrongwithit.
Assumingitisproperlyinstalledwithappropriategas,water,
andelectricconnections,thefollowingishowitshould
operate:
1) ACTIVATION
a. Ahotwatertapisopenedenoughthattheflow
sensordetectsaflowratethroughtheheatergreater
thantheactivationpointof0.75gpm.
b. Thefanactivatesafterflowisdetected.
c. Thecomputerchecksforanyproblemswiththeunit
beforestartup.
d. Igniteractivates.Youcanhearthebuzzingofthe
sparkigniter.
e. Maingasvalve,proportionalvalve,andsolenoidgas
valveswillopen.Youwillhearadeep“clunkclunk”
noise.
f. Onceaflameisdetected,theredLEDlocatedonthe
computerboardwillactivate.
g. Inamulti‐heatersetup,thecontrollerwillactivatethe
nextheaterin2‐4gpmincrements,dependingonthe
settemperature.
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2) OPERATION
a. Theproportionalgasvalvewillmodulatebasedontheamountofhotwaterdemandedandthe
temperatureriseneeded.Thefanspeedwillmodulateaswelltocreateanefficientburn.
b. Youwillnoticethatonlypartialsectionsoftheburnerwillbelit.Thisisnormaloperation;there
arethreesectionsontheburnerassembly,andthecomputercontrolstheamountofsections
neededbasedontheflowrateandtemperatureriserequired.
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3) SHUTDOWN
a. Theheaterwillshutdownwhenthewaterflowratedropsbelowthedeactivationpointof
0.4gpm.
b. Theheaterwillclosethemaingasvalveandsolenoidgasvalves,extinguishingtheflame.
c. WhentheflamedisappearstheredLEDwillturnoff.
d. Thefanwillincreaseinspeedtopurgetheventingofanyremainingexhaustgases.Thelength
ofpost‐purgecanlastupto1½minutes.
e. Theheatergoesintostandbywaitingfortheprocesstobeginagain.
*Thepurposeofthisdiagramistoillustratethe
tanklesswaterheaterdesignconcepts,and
maynotbeaccuratetoyourmodelsphysical
description.
Figure2

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4.INSTALLATION
1. Followalllocalcodes,orintheabsenceoflocalcodes,followthemostrecenteditionofthe
NationalFuelGasCode:ANSIZ223.1/NFPA54intheUSAorCAN/CSAB149.1NaturalGas,
PropaneInstallationCodeinCanada.
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2. Allgaswaterheatersrequirecarefulandcorrectinstallationtoensuresafeandefficient
operation.Thismanualmustbefollowedexactly.Readthe“SafetyGuidelines”sectioninthe
installationmanual.
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3. Themanifoldgaspressureispresetatthefactory.Itiscomputercontrolledandshouldnot
needadjustment.
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4. Maintainproperspaceforservicing.Installtheunitsothatitcanbeconnectedorremoved
easily.RefertotheClearancesSectiononp.8intheinstallationmanualforproperclearances.
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5. Thewaterheatermustbeinstalledinalocationwheretheproperamountofcombustibleair
willbeavailabletoitatalltimeswithoutobstructions.
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6. Theelectricalconnectionrequiresameansofdisconnection,toterminatepowertothewater
heaterforservicingandsafetypurposes.
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7. Donotinstalltheunitwheretheexhaustventispointingintoanyopeninginabuildingorwhere
thenoisemaydisturbyourneighbors.Makesuretheventterminationmeetstherequired
distancebylocalcodefromanydoorwayoropeningtopreventexhaustfromenteringa
building.
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8. Particlesfromflour,aerosols,andothercontaminantsmayclogtheairventorreducethe
functionsoftherotatingfanandcauseimproperburningofthegas.Regularlyensurethatthe
areaaroundtheunitisdust‐ordebris‐free;regularmaintenanceisrecommendedforthese
typesofenvironment.

9. Ifyouwillbeinstallingthewaterheaterinacontaminatedareawithahighlevelofdust,sand,
flour,aerosolsorothercontaminants/chemicals,theycanbecomeairborneandenterandbuild
upwithinthefanandburnercausingdamagetothewaterheater.

10. FortheIndoor110(T‐KJr2‐IN),310(T‐K4‐IN),and510(T‐D2‐IN)models:
•Theseunitsmaybeconvertedtoadirect‐vent(sealedcombustion)appliancebyinstallinga
direct‐ventconversionkit(PartNo.9007667005)whichwillbringinallrequired
combustibleairfromoutsidethebuilding.Wheninstallingtheconversionkit,pleasefollow
allinstructionsincludedwiththekit.
•Ifthewaterheaterisusedasadirect‐ventappliance,theunitrequiresa3”intakeairpipe.
Theintakepipemustbesealedairtight.AirsupplypipecanbemadeofABS, PVC,
galvanizedsteel,corrugatedaluminum,corrugatedstainlesssteelorCategoryIIIstainless
steel.
•Terminatingtheventingthroughasidewallisrecommendedforthedirect‐ventsystem.
•Runningtheexhaustventandtheintakepipeparallelisrecommended.
•Terminatingtheexhaustandintakeonthesamewall/surfaceisrecommended.
Terminatinginthesamepressurezoneallowsforpressurebalancing,whichprevents
nuisanceshutdowns.Followventingclearanceguidelinesintheinstallationmanual.

11. ForOutdoor110(T‐KJr2‐OS),310(T‐K4‐OS),&510(T‐D2‐OS):
•Tobeinstalledoutdoorsandonlyinareaswithmild,temperateclimates.

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5.TROUBLESHOOTING
5.1PRELIMINARYCHECKLIST
Checkallofthesebasicitemsbeforeproceedingontoanyothersection:
•GAS/WATER/ELECTRIC:
oThegassupplyvalveshouldbefullyopen.
oVerifythecorrectgastypeisbeingused,NGorLP.
oThewatersupplyvalveshouldbefullyopen.
oTheunitshouldbeconnectedtoa120VAC60Hzpowersupply.Thiscanbeverifiedby
observingthecomputerboard3‐digitLEDdisplay.Ifitisnotlit,thecomputerboardis
notbeingpowered.ChecktoseeiftheON/OFFswitchbelowthefuseboxissettothe
onposition,orifthefuseinthefuseboxisblown.
•REMOTE:Ifyouareusingaremotecontroller,theremote’spowerbuttonmustbeturnedon.
•HIGHALTITUDE:Isyourlocationatanaltitudeofover3000feet?Thismaycausealackofair.
SeethehighaltitudeprocedureintheTroubleshootingProceduressection.
•HARDWATER:Whatisthehardnessofthewater?Asoftenerisalwaysrecommended,butif
thewaterisabove7grainsofhardnessor70‐140ppm,onemustbeinstalled.Ifthereisno
watersoftenerinstalled,existinginstallationswillgraduallyaccumulatescalebuilduponthe
heatexchangerandcausealeak.Heatexchangerfailuresdotohardwaterscalearenot
coveredunderthewarranty.
•NEWINSTALLATIONS:Isthisinstallationafewyearsoldorbrandnew?
oAunitthathasworkedproperlyforawhilebutisnowstrugglingmayhavebecome
scaleduporcontainsadirtyburner.
oAnewinstallationmostlikelyisinstalledorplumbedincorrectly.
•EXTERNALPROBLEM:Testwhethertheproblemiswithintheunitorexternaltotheunit(i.e.in
theplumbingsystem)byattemptingtorunhotwaterlocallythroughthepressurereliefvalve
(PRV).
oDoestheheaterigniteandremainrunningproperly?Ordoestheheatershutdowninto
anerrorcode?IfitrunsfinethroughthePRVtheplumbingsystemisatfault.


NEXTSTEP:Finally,checktoseeiftheunithasanerrorcode.Theerrorcodewillbedisplayedonthe
sevensegmentLEDonthebottomleftofthecomputerboard.Seefigures4and5.
•Ifitisdisplayinganerrorcode,proceedtotheErrorCodessection(p.12).
•Ifthereisnoerrorcode,proceedtotheGeneralProblemssection(p.8).
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5.2TROUBLESHOOTING‐GENERALPROBLEMS
ProceedtotheErrorCodessectionifanerrorcodeisidentified.Forothercommonproblemsthatdo
notinvolveanerrorcode,seeifthefollowingitemshelp:
Thewaterisnothotenough.
Thewateristoohot.
Temperaturefluctuateswhenafixtureisopened.
Unitdoesnotignitewhenwatergoesthroughit.
Ittakesalongtimetogethotwateratthefixtures.
Thefanmotorisstillspinningafteroperationhasstopped.
Abnormalsoundscomefromtheunit.
Lossofpressureatallsinkswhenthedishwasherfills.
Unithaspower,gas,andwaterbutdoesnotturnon.
MultipleHeaterSetup(Easy‐Link)
THEWATERISNOTHOTENOUGH
•Comparetheflowandtemperatureatthepressurereliefvalve.
oIfthetemperatureandflowratearecorrectatthePRVthentheproblemresidesinthe
plumbingline,notinthetanklessunit.Checkforacrossconnectionorotherwaterline
problems
•Testthehotwatertemperaturewithahandheldthermometertomeasurehowfaroffthewater
temperatureisfromthesettemperature.
oThesettemperaturemaybesettoolow.Thetemperaturecanbechangedwiththe
pushbuttonsonthePCBorbytheremotetemperaturecontroller,ifoneisinstalled.
•Checkforcrossplumbingbetweencoldwaterlinesandhotwaterlines.SeetheProcedures
section(p.21)forinstructions.
•Unitmaybehardwaterscaled.Thescaleactsasaninsulatorpreventingtheheatexchanger
fromtransferringheattothewater.ContactaTakagiServiceAgent.
•Theunitmaynotbereceivingenoughgas.
oThegassupplyvalvemaynotbefullyopen.
oThegaslinemaybesizedimproperly.
oThegassupplypressuremaybetoolow.Thismaybecausedbyamalfunctioninggas
supplyregulator,sochecktoseeifyourregulatorisworkingproperly.
•Checktoseethatacheckvalveisinstalledbetweenthepumpdischargeandtheconnectionto
thecoldwatersupply.Inspectthecheckvalveforproperoperation.Ifthereisn’toneinstalled,
orifitismalfunctioning,coldwatermaybeback‐feedingintothesystem.
•Double‐checkfora101errorcode.A101errorcodewillreducetheamountofgasinputinto
theheater.
•Outputtemperaturewillbeaffectedifairflowisimpeded.
oCheckconstructiondustanddebrisinventing,suchasdrywall.
oIfthereisdustinsidethecabinet,therewillalsobedustinsidetheburnerandheat
exchanger.Seetheprocedureforcleaningtheburner(p.26).

THEWATERISTOOHOT
•Thesettemperaturemaybesettoohigh.Thetemperaturecanbechangedwithdipswitcheson
thePCBorbytheremotetemperaturecontroller,ifoneisinstalled.

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•Theflowadjustmentvalvecouldbeobstructedduetohardwaterscaleordebris,causinglower
thanexpectedwaterflow.Verifywaterflowwithagraduatedcontainerorwiththeremote
temperaturecontroller,ifoneisinstalled.
•Theoutputthermistorcouldbecompromised.Thiscomponentmaybecheckedbyenteringthe
DiagnosticsModeonaremotecontroller,ifoneisinstalled.Turnpowerofftotheunitandrun
coldwaterthroughit;checktoseeiftheinletandoutlettemperaturesreadthesameonthe
remote.Forinstructionsonhowtodothis,refertotheMaintenanceSheet,packagedwith
everywaterheaterandlocatedbehindthefrontpaneloftheunit.
TEMPERATUREFLUCTUATESWHENAFIXTUREISOPENED
•MakesuretheunitisinstalledproperlyusingtheProperInstallationsection(p.6)ofthisguide.
•Checktheflowandtemperaturerightattheunitatthepressurereliefvalve.Iftheflowrate
andtemperaturearecorrectatthePRV,thentheproblemresideselsewhereintheplumbing
line.Thefollowingcouldbeplumbinglineproblems:
oCheckforcrossplumbingbetweencoldwaterlinesandhotwaterlines.Seethe
Proceduressection(p.21)forinstructions.
oChecktoseethatacheckvalveisinstalledbetweenthepumpdischargeandthe
connectiontothecoldwatersupply.Inspectthecheckvalveforproperoperation.If
thereisn’toneinstalled,orifitismalfunctioning,coldwatermaybeback‐feedinginto
thesystem.
oProblemswitharecirculationsystem:
Checkthatacheckvalveisinstalledbetweenthepumpdischargeandthe
connectiontothecoldwatersupply.
Checktoseeifthepumpisoperatingproperly.
Checkforaircavitation.Thepumpwillbeveryhotorchattering.
Checkthedirectionalindicatoronthepumpflange.
Checkthesizingofthepump–aminimumflowof2gpmisrequired.
•Checkgassupply
oVerifythegassupplylinesaresizedforthemaximumBtu/hdemand,asindicatedinthe
ProperInstallationsection(p.6)ofthisguide(Seethespecificationpagep.3atthe
beginningofthismanualforgasinputrating).
oForLPmodels,theremaynotbeenoughgasleftinthepropanetank.
oVerifythatthesupplygaspressureiswithinspecification,notonlywhentheheaterisin
standby,butwhiletheheaterisrunningonmaximumfireaswell.Thismaybecaused
byamalfunctioninggassupplyregulator.
•Venting
oVerifythattheexhaustventingisinstalledtomanufacturer’sspecification.
oVerifythattheventrundoesnotexceedthemaximumlimit(50ft.)
•Thefilteroncoldwaterinletshouldbeclean;lookforsignsofhardwaterscaling.
•Checktomakesurethatthecleartubebetweentheproportionalgasvalveandthebottomof
thecombustionchamberisconnected.
•Onwellsystemsorevenonsomecitywatersystems,waterpressurefluctuations(especiallyon
lowflow)of8to10psiwillresultinflowratefluctuations,whichwillinturnresultinminor
temperaturefluctuations.
•Flowsensororwatercontrolvalvemaybecompromised.ContacttheTechnicalDepartment.
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TroubleshootingGuide
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UNITDOESNOTIGNITEWHENWATERGOESTHROUGHIT
•Istheflowrateover0.75gpm?Seeiftheunitinitiateswhenyouincreasedemandofwater
beingdrawnthroughtheunit(e.g.openingupmorehotfixtures).
•Checkthatthegaslineisopenandispurgedofair(p.22).
•Checkthatthefilteronthecoldwaterinletisclean(p.21).
•Checkforreverseconnectionandcrossconnection(p.21).
•Problemswithrecirculationsystem
oSeethatacheckvalveisinstalledbetweenthepumpdischargeandtheconnectionto
thecoldwatersupply.Amalfunctioningormissingcheckvalvewillcausecoldwaterto
back‐feedintothesystem.
•Ifyouusetheremotecontroller,istheremotepowerbuttonturnedon?
•ChecktoseeiftheComputerboardisreceivingpower.Thiscanbeverifiedbyobservingthe
computerboardredLED.
oIfitisnotlit,thecomputerboardisnotbeingpowered.ChecktoseeiftheON/OFF
switchbelowthefuseboxissettotheonposition,orifthefuseinthefuseboxis
blown.
•Ifthefandoesnotinitiateatallanditisverifiedthattheunitispowered(seeabove),theflow
sensormaynotbeworkingproperly.Checktheflowsensorforproperimpellerfunctionality.
ITTAKESALONGTIMETOGETHOTWATERATTHEFIXTURES
•Thetimeittakestodeliverhotwatertoyourfixturesdependsonthelengthofpipingbetween
thetwo.Thelongerthedistanceorthebiggerthepipes,thelongeritwilltaketogethotwater.
Ifthisisthecaseandyouwouldliketoreceivehotwatertoyourfixturesquicker,youmaywant
toconsiderahotwaterrecirculationsystem.
•Problemswiththerecirculationsystem.
oSeethatacheckvalveisinstalledbetweenthepumpdischargeandtheconnectionto
thecoldwatersupply.Amalfunctioningormissingcheckvalvewillcausecoldwaterto
back‐feedintothesystem.
THEFANMOTORISSTILLSPINNINGAFTEROPERATIONHASSTOPPED
•Thisisnormal.Afteroperationhasstopped,thefanmotorkeepsrunning
from5to50secondsinordertore‐ignitequickly,aswellaspurgeallthe
exhaustgasoutoftheflue.
ABNORMALSOUNDSCOMEFROMTHEUNIT
•Checkthefanfordebris.
•ContacttheTechnicalServiceDepartment.
LOSSOFPRESSUREATALLSINKSDURINGCOMMERCIALDISHWASHERFILLS
•Verifythecapacityoftheheater(s)versustheGPMdemandofthedishwasher.
•Checkthesizeofthesupplylinestothedishwasher.
•Lookforawaterregulatoronthedishwasher.Checkthedishwasherratingplatetoconfirmthe
recommendedsupplywaterpressure.
•Unitmaybehardwaterscaled.Scalecanreducepressureandflowofwaterthroughtheunit;
thiscanoccurasquicklyasafewmonths.
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Figure3

TroubleshootingGuide
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UNITHASPOWER,GAS,ANDWATERBUTDOESNOTTURNON
•Fornewunitinstalls,checktomakesuretheunitisnotplumbedinbackwards.
oShutoffcoldwaterfeedonly.
oOpennearesthotwatertap.Waterflowshouldstop.Ifnotthereisacoldwatercross
connection.
oOpenPressureReliefValve.Waterflowshouldstop.Ifnotunitisplumbedin
backwards.
•Cleanthefilter(p.21).
•Ifthefanneverinitiates,checkforafouledwaterflowsensor(p.31).
EASY‐LINKSYSTEMSETUP(MULTIPLEHEATERSETUP)
•RefertotheInstallationManualforpropersetup.
•UnitNumbering
oThemasterunitwillalwaysbeassignednumber1.Theremainingunitswillberandomly
assignednumbers2‐4(ifthereare4unitsintheEasy‐Linksystem).
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TroubleshootingGuide
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TM‐RE30(Optional)
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5.3TROUBLESHOOTING‐ERRORCODES
•Allunitsareselfdiagnosticforsafetyandconveniencewhentroubleshooting.
•Ifthereisaproblemwiththeinstallationortheunit,itwilldisplayanumericalerrorcodeon
theRemoteController(ifinstalled),onthe7‐SegLEDonthecomputerboard(510(T‐D2)),or
theflashingredLED(110(T‐KJr2),310(T‐K4))tocommunicatethesourceoftheproblem.
•Consultthefollowingchartforthecauseofeacherrorcode.
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Table2–ErrorCodes
ErrorCode
510(T‐D2)
7‐SegLED,
remote
ErrorCode
110(T‐
KJr2),310
(T‐K4)
Remote
ErrorCode
RedLED
110(T‐KJr2),
310(T‐K4)

MalfunctionDescription
031031IncorrectDipswitchSettings
101105Warningfor991ErrorCode
111113IgnitionFailure
121123FlameLoss
311312OutputThermistor
321322InletThermistor
331N/AN/AMixingThermistor
391392Air‐fuelRatioRodFailure
441N/AN/AFlowSensor(Easy‐LinkSystemonly)
510516AbnormalGasValves
N/A556AbnormalSolenoidGasValve
611614AbnormalFanMotor
651N/AN/AAbnormalFlowAdjustmentValve(Easy‐LinkSystemonly)
701701ComputerBoardFault
721726FalseFlameDetection
74174N/ARemoteControllerCommunicationFailure
761N/AN/ACommunicationFailure(Easy‐LinkSystemonly)
991995Abnormalcombustion
Errorcodeon
theTK‐RE02

Errorcodeonthe
computerboard
RedLED
Errorcodeon
theTM‐RE30
Errorcodeonthe
computerboard
7‐SegLED
Figure4
–
310(T‐K4),110(T‐KJr2)ErrorCodeoutputs Figure5
–
510(T‐D2)ErrorCodeoutputs

TroubleshootingGuide
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ERRORCODE031[510(T‐D2)],ONEFLASH/03[110(T‐KJR2),310(T‐K4)]
INCORRECTDIPSWITCHSETTINGS
1) Turnoffthepowersupply.
2) Removefrontcoverandlocatethedipswitchesonthecenterofthecomputerboard.
3) Checkthedipswitchsettingsontheleftandrightbanks.Refertop.19forthecorrectdipswitch
positions.
a. Gastypeisacommondipswitcherror.
b. MostotherswitchesshouldbeondefaultsettingUNLESStheparticularsetuprequires
otherwise.
c. Easy‐Linksystems:Themasterheatershallhavethenumber10dipswitchontherightbankin
theONposition(left).Theremainingheaters(theslaveheaters)willhavethenumber10
dipswitchintheOFFposition(right)andthecommunicationwireswillbeattachedtotheslave
in/outplugs.
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ERRORCODE101[510(T‐D2)],FIVEFLASHES/10[110(T‐KJR2),310(T‐K4)]
ABNORMALCOMBUSTION
1) Blockageintheairway.Checkthefollowingareas:
a. Ventinglengthobstruction(Birds’nests,trash,etc.)
b. Backflowpreventerinstalledbackwards
c. Heatexchanger
d. Fan
2) Checkthemanifoldpressure(p.22).Adjustthemanifoldpressuretothecorrectvaluesifnecessary.
3) Ifintakeairiscontaminatedwithdust,lint(laundrymachinenearby),grease(kitchens),orother
contaminants,cleantheburner.Seep.26onproceduresforcleaningtheburner&rodassembly.
4) Weatherrelatedissues:highwinds,frozenventterminationflap,etc.
5) Installationsataltitudesaroundorover3000feet:Changedipswitchesonthecomputerboardfor
FM+modes.Seedipswitchexplanationsonpage19.
6) Makesurealldipswitchesaresetproperlyforthetypeofinstallation.
7) Ifthecauseofthe101errorcodehasbeendeterminedandsolved,resetthecomputerboardto
cleartheerrorcode(p.23).
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ERRORCODE111[510(T‐D2)],THREEFLASHES/11(110[T‐KJR2),310(T‐K4)]
IGNITIONFAILURE
Heaterdoesnotfireafterthreefailedattemptsatignition.
1) Verifythatthehi‐limitswitchisnottripped.Turnthe
powerofftotheunit.Pushthewhitebuttonin.The
switchwillresetwhenyouhearandfeelthebuttonclick.
Turnthepowerbackonandtesttheheater.Iftheunit
fireson,thecauseofthehi‐limittripmustbedetermined.
PleasecontacttheTechnicalServiceDepartmentfor
furthertechnicalsupport.
2) Checkthegassupply.Verifythatsufficientgasisbeing
suppliedtotheheaterandthegaslineisclearofdebrisor
anyair.Purgethelineofairifneeded(p.22).
a. Itispossiblethereisafaultypressureregulatoratthe
Figure6

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gasmeter.
b. Forpropaneunits,colderperiodsofthedayresultinacoldregulatorandmaycausethis
problem.
3) Verifythatthegassupplypressureiswithinspecificationswhentheheaterisinstandbyandwhen
theheaterisrunning.
4) Checkthattheclearplastictubeconnectingtheproportionalgasvalvetothecombustionchamber
isattached.
5) Theoverheatcutofffuse(OHCF)mayhavebeencompromised.Forproceduresonhowtocheck
whethertheOHCFisintact,refertop.24.IftheOHCFhasbeencompromised,contactthe
TechnicalServiceDepartmentforfurtherassistance.
6) Ifflamecomesonforonly1‐2secondsbeforegoingout,cleantheflamesensor(p.25).
7) Checktheigniterforaspark.Thesparkmaybeviewedthroughthesightglasslocatednexttothe
igniterandflamesensor.
a. Astrongbluesparkwillremainsteadyandinplace,whileaweaksparkwilljumparound.
b. Ifnosparkoraweaksparkisobserved,checktheigniterwireconnectionsandmakesurethese
aresecure.Ifthesearesecure,areplacementigniterwillberequired.
8) Checkforblockagesintheventing,suchasbirdnests,animals,ortrash.
a. PCBoardfaultorGasSolenoidfault.ContacttheTechnicalServiceDepartment.
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ERRORCODE121[510(T‐D2)],THREEFLASHES/12[110(T‐KJR2),310(T‐K4)]
FLAMELOSS
Thiserrorcodeappearsiftheflamesdisappearwhiletheunitisstillsupposedtobeinoperation.
1) Verifythatthehi‐limitswitchisnottripped.Turnthepowerofftotheunit.Pushthewhitebutton
in.Theswitchwillresetwhenyouhearandfeelthebuttonclick.Turnthepowerbackonandtest
theheater.Iftheunitfireson,thecauseofthehi‐limittripmustbedetermined.Pleasecontactthe
TechnicalServiceDepartmentforfurthertechnicalsupport.
2) Checkthegassupply.Verifythatsufficientgasisbeingsuppliedtotheheaterandthegaslineis
clearedofdebris.
a. Itispossiblethereisafaultypressureregulatoratthegasmeter.
b. Forpropaneunits,colderperiodsofthedayresultinacoldregulatorandmaycausethis
problem.
3) Verifythatthegassupplypressureiswithin
specificationswhentheheaterisinstandbyandwhen
theheaterisrunning.
4) Checkthattheclearplastictubeconnectingthe
proportionalgasvalvetothecombustionchamberis
attached.
5) Iftheflamecomesonfor1‐2secondsbutthengoes
out,cleantheflamesensor(p.25).
6) Theoverheatcutofffusemayhavebeen
compromised.Forproceduresonhowtocheck
whethertheOHCFisintact,refertop.24.Ifithas,
contacttheTechnicalServiceDepartmentforfurther
assistance.
7) Checkforblockagesinventing,suchasbirdnests,animals,ortrash.
8) PCBoardfaultorGasSolenoidfault.
a. Ifoneoftheseissuspectedtobetheproblem,contacttheTechnicalServiceDepartment.

Figure7

TroubleshootingGuide
15|Page

ERRORCODE311[510(T‐D2)],TWOFLASHES/31[110(T‐KJR2),310(T‐K4)]
OUTPUTTHERMISTOR
1) Checkthatthewireconnectionsaresecureandfreeofburns
orcuts.Theoutputthermistorislocatedontheheat
exchangerontherightside.
2) Checktheresistancevalue;itshouldbeabout9.0kΩatroom
temperature(about74°F).
3) Cleanthethermistor.
a. Draintheunitofwater.Seep.21. 
b. Removethefastenerholdingtheoutputthermistorand
pulloutthesensorprobe.Cleantheprobetoasilver
finish.Donotlosetherubbero‐ringthatwrapsaround
thissensor.
c. Replaceandtest.
4) Iftheerrorcodepersists,replacethethermistor.

ERRORCODE321[510(T‐D2)],TWOFLASHES/32[110(T‐KJR2),310(T‐K4)]
INLETTHERMISTOR
1) Checkthatthewireconnectionsaresecureandfreeofburnsorcuts.Theinletthermistoris
embeddedinthewaterinletconnection.
2) Checktheresistancevalue;itshouldbeabout9.0kΩatroomtemperature(about74°F).
3) Cleanthethermistor.
a. Draintheunitofwater.Seep.21.
b. Removethecomputerboardtoaccesstheinletthermistor.Thecomputerisfixedinplacebya
singlescrewatthetopoftheboard.
c. Removethescrew,pulloutthesensorprobe.Cleantheprobetoasilverfinish.Donotlosethe
rubbero‐ringthatwrapsaroundthis
sensor.
d. Replaceandtest.
4) Iftheerrorcodepersists,replacethe
thermistor.

ERRORCODE331[510(T‐D2)]
MIXINGTHERMISTOR
1) Checkthatthewireconnectionsaresecure
andfreeofburnsorcuts.Themixing
thermistorisembeddedinthewateroutletconnection.
2) Checktheresistancevalue;itshouldbeabout9.0kΩatroomtemperature(about74°F).
3) Cleanthethermistor.
a. Draintheunitofwater.Seep.21.
b. Removethecomputerboardtoaccessthemixingthermistor.Thecomputerisfixedinplaceby
asinglescrewatthetopoftheboard.
c. Removethescrew,pulloutthesensorprobe.Cleantheprobetoasilverfinish.Donotlosethe
redrubbero‐ringthatwrapsaroundthissensor.
d. Replaceandtest.
4) Iftheerrorcodepersists,replacethethermistor.
Figure8
Figure9

TroubleshootingGuide
16|Page


ERRORCODE391[510(T‐D2)],TWOFLASHES/39[110(T‐KJR2),310(T‐K4)]
AIR‐FUELRATIORODFAILURE
1) Checkthatthewireconnectionsaresecureandfreeof
burnsorcuts.
2) Checkthattheclearplastictubeconnectingthe
proportionalgasvalvetothecombustionchamberis
attached.
3) CleantheAFR(p.25).

ERRORCODE441[510(T‐D2)]
FLOWSENSOR
PartofanEasy‐Linksystem(510(T‐D2)only),themasterunit
signaledforanadditionalheatertoactivateanditdidnot.
1) Verifythatwaterisbeingsuppliedtotheheaterinerror.
2) Verifythatthewiresareconnectedtothecomputerboard.
3) Checktheinletfilterforanydebris.Seep.21.
4) Checktheflowsensorfordebris.

ERRORCODE510[510(T‐D2)],SIXFLASHES/51[110(T‐
KJR2),310(T‐K4)]
ABNORMALGASVALVES
Drivingcircuitfaultforthemainorsolenoidgasvalves.
1) Ifthehotwaterisshutoff,butflames
arestillvisiblethroughthesightglass,
immediatelyshutoffgasandpowerto
theunitandcontacttheTechnical
ServiceDepartment.
2) Checkthewireconnectionstothegas
valveassemblyforburnsorcuts.
3) Iftheunitwasrecentlyrebuilt,make
surethateachgasvalvewireisplugged
intotheproperplace.
4) Verifythatthesupplygaspressureis
withinthespecifiedlimits.Toohighof
aninletgaspressuremaycausethe
maingasvalvetojamorcouldbedamaged.

ERRORCODESIXFLASHES/55[110(T‐KJR2),310(T‐K4)]
ABNORMALSOLENOIDGASVALVE
Drivingcircuitfaultforthesolenoidgasvalve.
1) Ifthehotwaterisshutoff,butflamesarestillvisiblethroughtheburnersightwindow,immediately
shutoffgasandpowertotheunitandcontacttheTechnicalServiceDepartment.
2) Checkthewireconnectionstothegasvalveassemblyforburnsorcuts.
3) Iftheunitwasrecentlyrebuilt,makesurethateachgasvalvewireispluggedintotheproperplace.
4) Verifythatthesupplygaspressureiswithinthespecifiedlimits.Toohighofaninletgaspressure
maycausethemaingasvalvetojamorcouldbedamaged.

Figure10
Figure11
Figure12

TroubleshootingGuide
17|Page

ERRORCODE611[510(T‐D2)],FOURFLASHES/61[110(T‐KJR2),310(T‐K4)]
ABNORMALFANMOTOR
1) Turnoffpowersupply.
2) Checkfanmotorwiringforanybreakages,burnmarksonthePCboard,ormoisture.Ifmoistureis
found,allowconnectiontocompletelydrybeforeturningpowerbackon.
3) Checkfanhousingforwater.Iffound,pleasedrythefan,thentestheater.
4) Toremovethefanmotor.
a. Turnoffthepowersupply.
b. Movethecomputerboardoutoftheway.
c. LocatethetwoPhillipsheadscrewsfittedatthetopof
thefanmotortothecombustionchamberbox.Two
holesarelocateddirectlyatthebottomofthecasethat
lineupwiththetwoscrews.Usingan8”screwdriver,
removethescrews.
d. Slidethefanouttowardstheleft.
e. Ifsignsofwaterareevident,watermayhavedamaged
thefanmotorrequiringreplacement.
5) Ifthe611errorcodestillappearsafterallitemshavebeenchecked,thePCBmayneedreplacement

ERRORCODE651[510(T‐D2)]
ABNORMALFLOWADJUSTMENTVALVE
1) Turnoffpowersupply.
2) Checkthatallwireconnectionsaresecureandfreeof
burns.Theflowadjustmentvalveislocatedbehindthe
computerboardandattachedtothecoldwaterinlet.
3) Checkforwaterleakagefromthevalve.
4) DoavisualinspectionofthePCB.Checkfor
connection/breakageofwiresand/orburnmarksonthe
board.PCBmayneedtobereplaced.
5) Theflowadjustmentvalvemayneedtobecleaned.To
remove,followthestepsbelow:
a. Removethefourwaterwayclipsoneachsideofthe
valves.
b. Slidethevalveupofftheinletwaterconnection.
c. Checkbothendsofthevalveforsedimentordebris.Useabrushordescalingsolutionto
removethesediment.
d. Re‐installthevalveandclips.
e. Testtheheater.
6) Theflowadjustmentvalvemayneedtobereplacedifthevalvecannotbecleaned.

ERRORCODE701[510(T‐D2)],ONEFLASH/70[110(T‐KJR2),310(T‐K4)]
COMPUTERBOARDFAULT
1) Turnoffthepowersupply.
2) Checkallwireconnectionsandmakesuretheyaresecureandfreeofburnsorcuts.
3) InspectthePCBforconnection/breakageofwiresand/orburnmarksontheboard.
4) Verifythatsupplygaspressureiswithinspecifications.
5) ContacttheTechnicalServiceDepartmentforfurtherassistance.
Figure13
Figure14

TroubleshootingGuide
18|Page


ERRORCODE721[510(T‐D2)],SIXFLASHES/72[110(T‐KJR2),310(T‐K4)]
FALSEFLAMEDETECTION
1) Firstandforemost,shutoffallgasandpowertotheunit.Theproblemcouldbetheflamesensor,
butifitisn’t,thisisaverydangeroussituation.
2) ContacttheTechnicalServiceDepartmentforfurtherassistance.

ERRORCODE741[510(T‐D2)],74[110(T‐KJR2),310(T‐K4)]
MAINREMOTECONTROLPROBLEM
Thiserrorcodeonlyoccurswhenthereisamiscommunicationbetweenthetemperatureremote
controllerandthewaterheater.
1) Checkthatallwiringisproperlyconnectedtotheremote.
2) Verifythecorrectmodelofremoteisbeingusedforthecorrespondingtanklessmodel.
3) Verifythatonlyaremoteisinstalled.Multipleremoteswillresultinthiserrorcode.
4) Ifyoudisconnecttheremotefromtheheaterwiththepowersupplyon,thiserrorcodewillresult.
Turnoffpowerbeforedisconnectingtheremotefromtheheater.
5) Checkforanysignsofpowersurges.

ERRORCODE761[510(T‐D2)]
COMMUNICATIONFAILURE
1) Thiserrorcodeonlyoccursinamultipleheatersetup,wherethereisamiscommunicationbetween
masterandslaveunitsforEasy‐Linksystems.
2) Thiserrorcodewillonlybedisplayedonthemasterheater.
3) Thiserrorindicatesthatthemasterunithaslostcommunicationwiththeindicatedheater.
4) Verifythatthereispowertotheunitthathaslostcommunication.
5) SeetheInstallationManualforpropercommunicationcablesetup.
6) Checkforsignsofpowersurges.

ERRORCODE991[510(T‐D2)],FIVEFLASHES/99[110(T‐KJR2),310(T‐K4)]
ABNORMALCOMBUSTION
1) Refertoerrorcode101.
2) ContacttheTechnicalServiceDepartmentforfurtherassistanceifnothinghasworkedsofar.The
manifoldgaspressuremayneedadjustment.
3) Ifyouaresurethattheproblemhasbeensolved,resetthecomputer(p.23).
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TroubleshootingGuide
19|Page
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5.4TROUBLESHOOTING‐PROCEDURES
VerifyingproperDipswitchsettings…p.19
Drainingtheunit………………………………p.21
Cleaningthefilter…………………………….p.21
CheckingforaCrossConnection………p.21
CheckforReverseConnection………….p.21
Checkgassupplypressure……………….p.21
Purgethegaslineofair…………………..p.22
Adjustingmanifoldpressure…………….p.22
Resettingthecomputerboard…………p.23
CheckingtheOHCF………………………….p.24
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VERIFYINGPROPERDIPSWITCHSETTINGS:
•IncorrectDipswitchsettingscancausea031errorcode,oranumberofoperationalproblems.
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Table3–310(T‐K4),110(T‐KJr2)DipswitchSettings
No.FunctionONpositionOFFposition
1GastypePropaneDisable
2NaturalGasDisable
3FM+,FM++,FM+++110Indoor(T‐KJr2‐IN),310Indoor(T‐K4‐IN)
No.3
OF positionNposition
No.4OFFposition0%+6%
ONposition+12%+18%
110Outdoor(T‐KJr2‐OS),310Outdoor(T‐K4‐OS)
No.3
OFFpositionONposition
No.4OFFposition0%+4%
ONposition+8%+12%

4
5N/AN/AN/A(Default)
6ModeltypeOutdoor110(T‐KJr2‐OS),
Outdoor310(T‐K4‐OS)
Indoor110(T‐KJr2‐IN),
Indoor310(T‐K4‐IN)
7Outputtemperaturesettings(Default122F)
8
DipswitchBank
Figure15

TroubleshootingGuide
20|Page
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Table4–510(T‐D2)DipswitchSettings:UPPERBANK
No.FunctionONpositionOFFposition
1GastypePropaneDisable
2NaturalGasDisable
3AllowadjustmentsoffanmotorspeedEnableDisable(Default)
4FM+,FM++,FM+++Indoor510(T‐D2‐IN)
No.4
OFFpositionONposition
No.5OFFposition0%+6%
ONposition+12%+18%
Outdoor510(T‐D2‐OS)
No.4
OFFpositionONposition
No.5OFFposition0%+4%
ONposition+8%+12%
5
6N/AN/AN/A(Default)
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Table5.4‐510(T‐D2)DipswitchSettings:LOWERBANK
No.FunctionONpositionOFFposition
1Parent/ChildsettingforEasy‐LinksystemsParentChild(Default)
2ModeltypeIndoor510(T‐D2‐IN)
(Default)
Disable
3Outdoor510(T‐D2‐OS)
(Default)
Disable
4Outputtemperaturesettings(Default122˚F)
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5
6
Upperbankofdipswitches
Lowerbankofdipswitches
Figure16