Heatrex 797 SERIES Assembly instructions

INSTALLATION, OPERATING &
MAINTENANCE INSTRUCTIONS FOR 797 &
798 SERIES PIPE INSERT HEATERS
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GENERAL
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HEATREXPipeInsertHeatersaredesignedtoprovideyearsof
troublefreeoperationifproperlyinstalledandmaintained.
Pleasereadandfollowtheseinstructionsforinstallingand
maintainingtheheater.
1
PipeInsertHeatersprovideaneffectivewaytoheatlargestorage
tanks.Theheatingelementdesignallowsremovalandservicing
oftheheatingelementwithoutdrainingthetank.
HEATERCONSTRUCTION
Theheatingelementsareopencoildesignandconsistofheavy
gaugenickel‐chromiumalloysupportedbyceramicinsulators.
Theceramicinsulatorsarefastenedtoastripofheavysheet
metal.
PIPE/TUBECONSTRUCTION
Theheatersshallbeinstalledinatubeorpipeofsufficientwall
thicknesstopreventthetubefromdistortingfromtheheat
generated.Thetubesshallbeconstructedsothattheheating
elementsmayberemovedwithoutdrainingthetank.When
specified,HEATREXcanprovideheaterpipes(798series).
Foradditionalproductofferings,refertoHEATREXcatalog
literatureonProcessHeatingsuchasCirculationHeaters,
ImmersionHeaters,orTubularHeatingElements.RefertoHX87‐
2000‐83forIndustrialControlPanelIOM.
Avarietyofdesigns,sizes,andmountingconfigurationsare
available.Theheaterwattdensityanddesignfeaturesmustbe
closelymatchedtotheapplication.
Lifeoftheheatingelementisdirectlyrelatedtoitssurface
temperature.
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Temperatureregulatingdevices,temperaturelimitingcontrols,
andlowliquidlevelcontrolsarerecommendedforusewithpipe
insertheaters,tocontroltheheatingprocessandsafeguardthe
heaterfromexcessivetemperaturesthatcancausedamage.
Also,damagetofluidcouldoccuriftheheaterisallowedto
exceedthemaximumfilmtemperaturerecommendedbythe
manufacturer.Heaterscanbeprovidedwithsheathsensing
thermocoupleswhenrequested.
HEATREXPipeInsertHeaterscanbespeciallydesignedforusein
hazardousareasasspecifiedinArticle500through516ofthe
NationalElectricalCode.Refertotheheaternameplateor
HEATREXApplicationDataforclassificationoftheheater
provided.SeesectionbelowlabeledHazardousAreasforspecific
requirements.
Itistheultimateresponsibilityoftheusertoverifythatthe
constructionmaterialsprovidedbyHEATREXaresuitablefor
usewiththeprocessfluid.Specifically,corrosionissuesmust
bereviewed.RefertoHEATREXApplicationDataforheater
constructionmaterialsanddesignconditions.
INSTALLATION
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HandlingandStorage
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Caremustbetakentoavoiddamagetotheheaterduringstorage
andhandling.WhenHEATREXprovidesheaterswithpipes,the
heatingelementisshippedinthepipe.Iftheheaterpipeisuser
supplied,theheatingelementwillbeshippedincardboard
shippingtubes.
CAUTION
FailuretofollowHEATREXrecommendationscouldresultin
prematurefailureand/orseriousequipmentdamage.
CAUTION
HEATREXrecommendsinstallationbeperformedbyqualified
personnelfamiliarwiththeNationalElectricalCodeandalllocal
codesandstandards.Itistheresponsibilityoftheinstallerto
verifythesafetyandsuitabilityoftheinstallation
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WARNING
DONOTmountheatersinanatmospherecontaining
combustiblegases,vapors,dusts,orfibersunlessproperly
markedassuitableforthecondition.Refertosectionbelowfor
specialinstructionsforHazardousAreas.
Protecttheheaterfromweatherdamageduringstorage.
Cardboardshippingtubesarenotsuitableforoutdoorstorage.
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Itisrecommendedtostoretheheaterinacooldryareatohelp
preventtheheatingelementceramicspacersfromdrawing
moisture.
WARNING
Hazardousvoltagesarepresentinthisequipment.Lockoutand
tagthebranchcircuitdisconnectswitchbeforeworkingonthis
heater.

MechanicalInstructions
SiteSelection
ReviewtheNEMATyperatingoftheheaternotedonthe
HEATREXApplicationData.Donotinstallaheaterinanareanot
consistentwithitsrating.
Allowsufficientfreespacearoundheaterinstallationsite.Work
spaceforheatermaintenanceshouldbeatleastthreefeetin
frontandoneithersideoftheheater.Theminimumpullspace
fortheheatingelementinstallationorremovalfromthe
pipe/tubeshouldbeatleastfourfeet.Theheatingelementis
designedtobeflexibleandcanbecurvedifnecessary.
Electricheatersarecapableofdevelopinghightemperatures.
Therefore,extremecareshouldbetakento
avoidmountingheatersinanatmospherecontaining
combustiblegases,vapors,dusts,orfibersunlessproperly
markedassuitableforthecondition.
HeaterOrientation
Thisstyleofheaterisintendedforhorizontaluseonly.Theopen
coilresistancewiremustnotbemountedinaverticalorientation
orfailurecouldoccurfromthecoilsagging.
Theheatermustbemountedplumbhorizontallytoassure
properoperation.
Thermalexpansionoftheheaterpipesmustbeconsideredwhen
locatingtheheater.Itcanbeapproximatedas:
Pipe
Length
(Inches)
x.00001x
MaxPipe
Operating
Temp(°F)
‐70°F
2
Iftheheaterisinstalledinapressurizedtank,areliefvalvemust
beinstalled.Asaminimum,thevalvemustbesizedtorelieveat
arateequaltotheratethattheheatercanthermallyexpand
fluidinthetank.
PipeInstallation
OnheaterpipesprovidedwithANSIflangedconnections,take
caretopreventscratchingtheflangefaces.HEATREXsuppliesa
non‐asbestosnitrilebondedfiberflangegasketunlessotherwise
requested.Theusermustconfirmthatthegasketissuitablefor
theapplication.Theusermustsupplyhighstrengthstudsorbolts
andnuts,suchasA‐193GR.B7andA194GR.2H,ratedforthe
designconditions.Boltsmustbeproperlyinstalledandtightened
topreventleaks.
Whenheaterpipesareweldeddirectlytotheuser’stankwall,
removetheheatingelementfromthepipebeforewelding.Refer
tothefollowinginstructionsforhandlingandremovingheating
elements.
Heaterpipesmustbesupportedinsidetheuser’stank.Supports
mustnotpreventthepipesfromthermallyexpanding.Supports
shouldbelocatedonamaximumspacingof10feet.
Wherebuildupofsolidsinthebottomofthetankisexpected,
thepipemustbelocatedabovethatlevel.Thepipemustalsobe
locatedbelowtheminimumoperatingfluidlevelofthetank.
Heaterpipesmustbeperfectlycleanbeforeinstallationof
heatingelement.Useonlyacleandryclothtoclean.Neveruse
alubricant.Compressedairwithalongwandmaybeusedto
removeceramicchips,etc.
IftheheaterpipeisnotsuppliedbyHEATREX,ensurethepipe
lengthiscorrectbymeasuringtheheatingelementoveralllength
(OAL),thecoldlengthfromthestartofthecoiledwiretothe
frontendoftheheatingelement(CL),andthelengthofthe
heaterpipenotincludingthepipecap(PL).
ThepipelengthPLmustbegreaterthanorequaltoOAL.When
locatingtheheaterpipeinthetank,thedistancefromthefront
endofthepipetotheexteriortankwallmustbelessthanor
equaltoCLtoensuretheheatedareaisinthefluid.
HeatingElementInstallation&Removal
Toremovetheheatingelementfromaheaterpipeorshipping
tube,firstremovethefasteningnutattheterminalend.Hold
theceramicinsulatorfirmlyinordertoavoidunduepressureon
theceramicandpossiblebreakage.Ifobstructionsare
encountered,rotatetheheaterslightlybackandforthwhile
pullingout.
Sinceheatingelementscanbeofconsiderablelength,itmaynot
alwaysbepossibletoremovetheelementinastraightline,due
tospacelimitations.Sincetheelementbarisflexible,the
elementmaybecurvedonaradiusof4feetminimum.Itis
recommendedthatatleast2peoplebeusedforthisprocedure,
inordertoavoidbreakingtheceramics.
Aftertheelementbarhasbeenremoved,itshouldbecarefully
stretchedoutonacleantableforinspection.Brokenceramics
mustbereplacedandburnspotsshouldbecleanedwithadry
cleanpaperorclothtowel.Oilorothercontaminationonthe
heaterwillcauseafailure.
Wheninstallingtheheatingelementintotheheaterpipe,reverse
thestepsnotedabove.
Heaterpipesmustbeperfectlycleanbeforeinstallationof
element.Useonlyacleandryclothtoclean.Neverusea
lubricant.Compressedairwithalongwandmaybeusedto
removeceramicchips,etc.
Theheatingelementintendedonlytobeinstalledwiththesheet
metalstriponthebottom.Donotrotatetheheaterinthepipe.
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CAUTION -Hazard of Electric Shock
Heatersmustbeboltedintopositionattheterminalend
topreventmovement,whichcouldallowtheheaterto
shortoutagainstthepipe.
Seefiguresattachedformountingconfigurations.
Thermalinsulationmustbeinstalledbetweenthefirstfew
ceramicsinthe“cold”sectionoftheheaterwheretheresistance
wireisnotcoiled.Aloosefillcerafiber(HEATREXP/N1008466)
orequal,ratedfor2000°F,ispreferred.Theinsulationmustbe
freeofmoistureorcontaminationinordertoprovideelectrical
isolation.Theinsulationisnecessarytoallow90°Cratedfield
wiring.
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InsulationWiringtotheheatershouldbepermanentlyinstalledinmetallic
ornon‐metallicelectricalgradeconduitinaccordancewithall
applicableelectricalcodes,andshouldincludeagrounding
conductorifnon‐metallicconduitisused.
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3
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WARNING
Surfacesoftheheaterpipeextendingbeyondtheuser’s
vesselmaybeextremelyhot.Avoidcontacttoprevent
p
ersonnelin
j
ur
y
orfire.Fieldsupplywiringmustberatedfor600Vac.Usecopper
conductors.
Theelectricalinstallationshouldincludeaservicedisconnect
switchinsightoftheheater,aswellasbranchcircuitover‐
currentprotectionandover‐temperatureprotection(ifaremote
controlpanelwasnotprovidedwiththeheater).
Thecustomermayprefertoinsulatetheflangeorpipeatthe
tankforpersonnelsafetyandenergyconservation.
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WARNING
Donotinsulatetheterminalenclosureorthefirst2”ofthe
pipe.Dangerousover‐heatingoftheterminalboxwiring
could result
.
Wherethermocoupleextensionwireisrequiredbetweenthe
heaterandcontrolpanel,verifyitisconnectedwithproper
polarityasshownonthewiringdiagram.Failuretodosomay
resultinanuncontrolledheater.Refertothewiringdiagramfor
therequiredwiretype.Shieldedwireisrecommendedtoreduce
signalinterference.
Theheatingelementsareprovidedwitha“coldsection”where
stainlesssteelbussingisusedtoconnecttotheheatingcoils.
Thisareamustbepackedwithinsulationtopreventover‐
temperatureoftheterminalenclosure.Refertowarningabove.Usecarewhenmakingconnectionstotheheatingelementto
avoidbreakingtheendceramic.


ElectricalInstructions

ThepotentiallyhighoperatingandambienttemperaturesofPipe
InsertHeatersrequirefieldwiringtotheheatertobecarefully
matchedtotheapplicationtoavoidseriousinjuryordamageto
theequipment.Thewiringmustbede‐ratedfortheexpected
terminalboxtemperature.Ifthecoldsectionoftheheateris
properlyinsulated,90oCminimumwiremaybeused.Referto
theNationalElectricalCode.




WARNING
Retightenallelectricalconnectionsthatmayhaveloosened
duringshipment.Failuretodosomayresultindamageto
theheaterorriskoffire.
Confirmallunusedconduitholesintheterminalboxaresealed
withplugssuitablefortheheaterenvironment.
Attachagroundconductortothemountingscrewfortheheater
intheterminalboxorbyotherappropriatemeansperNEC
Article250.
Thesizeandtypeofincomingfieldwiringwilldependuponthe
heaterterminalboxtemperature.Theterminalboxtemperature
isafunctionofthemaximumoutlettemperature,heatercurrent
drawperconductor,numberofconductorsperconduit,andwire
insulationrating.Fieldsuppliedconductorsmustbesizedforat
least125%ofthecircuitcurrent.
Besuretheterminalboxcoverisproperlyinstalledatalltimesto
ensurepersonnelprotection.Also,contaminantscancreate
leakage,(shock)hazards,permanentheaterdamageorfailure
andshouldbeavoided.
Tocalculatethecircuitcurrent(inamps):Itisrecommendedtoperformaninsulationresistancetestprior
toenergizingtheequipment.Ifthevalueislessthan1Megohm
usinga500Vdcorsimilartester,refertoMaintenanceand
Troubleshootingsections.
KWx1000Singlephase
LinecurrentLineVoltage

KWx1000
Threephase
Linecurrent1.732xLineVoltage




OPERATION

Duringinitialheating,itisrecommendedtoslowlyrampupthe
processsetpointandinspecttheheatingsystemforproblems.
DONOToperateheatersatvoltagesinexcessofthatmarkedon
theheater.Excessvoltagecanshortenheaterlifeoroverload
thebranchcircuitwiring.


DONOToperateheatersatpipetemperatureshigherthanthe
recommendedmaximum.Excesstemperaturescancause
prematurefailure.Generally,pipematerialsarelimitedtothe
followingmaximumtemperatures.
WARNING
DONOTTURNONHEATINGELEMENTSUNTILTANKIS
COMPLETELYFULLOFFLUID.Permanentdamagemay
resultifelementsareenergizedandtheheaterisnot
completelysubmerged.
Tooperatethisheater,ensurethetankiscompletelyfilledwith
liquid,andenergizethemainsupplydisconnect.Setthe
controllingdevicetothedesiredtemperature.




Pipe
Material
Maximum
PipeTemperature
Steel750°F
StainlessSteel3041400°F
4

HEATREXrecommendsthatallsafetyinterlocksbetestedduring
initialstartuptoensuretheyproperlydisabletheheater.After
10daysofoperation,retightenallelectricalconnections.
Onflangedheaters,re‐tightenheaterflangeboltsafterthe
heaterhascompletedoneortwoheatingcycles.

MAINTENANCE












Periodicallycheckallelectricalconnections,includingfieldand
factory‐madeconnectionsfortightness,andallwiringfor
deteriorationatleastonceayear.
Periodicallyinspectforleakageandretightenflangeboltswhen
required.
Inspecttheterminalenclosureandconduitconnectionsfor
evidenceofwaterleaksormoisturecollection.Tighten
connectionsasrequired.Donotcontinueusingaheaterwith
signsofdamage.
Caution,HEATREXrecommendsreplacingtheentirepipeinsert
assemblyundermostconditions.Theconditionoftheceramics
mustbeconsideredbeforeattemptingtoreplacecoils.Field
replacedheatingcoilsmustbeinstalledproperlyorfailuremay
occur.
Iffield‐replacingoneormoreheatingcoils,mechanical
connectionsattheendceramicsneedtoberemoved.Remove
theburnedoutcoilfrombothendsbypullinglightly,andatthe
sametimeturningthecoilbackandforth.Checktheceramics
neartheareawheretheburnoutoccurred.Brokenceramics
mustbereplaced,andburnspotsshouldbecleanedwithadry
cleanpaperorclothtowel.Oilorothercontaminationonthe
heatercoilorceramicswillresultinafailure.
Thenewcoilshouldbestretchedtothecorrectlength(donot
overstretch),andtheninsertedfromthefarend,bylightly
pushingwithaconstantback‐and‐forthturningmotion.After
thecoilisinplace,theloopattheendofthecoilshouldbe
guidedovertheboltontheendceramicandthentightenedin
placewiththepreviouslyremovedunit.
Installtheheatingelementbackintothepipeasnotedinthe
instructionsabove.
Wheretheheaterisinstalledincoldclimates,considersafety
precautionstopreventdamageduetofreezingfluidwhenthe
heaterisnotinservice.
TROUBLESHOOTING






Thenatureoftheceramicinsulatorsusedtoelectricallyisolate
andsupportthenickelchromiumresistancewireintheheating
elementsissuchthatoveralongperiodofstorage,theywill
absorbconsiderablemoisturefromtheatmosphereunlessthe
pipeandconduitsaresealed.Itisrecommendedtoperforman
insulationresistancetestpriortoenergizingtheequipment.If
thevalueislessthan1MegOhmusinga500Vdcorsimilar
tester,caremustbetakentodryouttheheatertoprevent
failure.Itisrecommendedthattheelementsbeturnedonata
reducedvoltageatfirsttoboiloffthemoisture.MegOhm
readingsmaydropinitiallyafterafewminutesofoperation,
indicatingmoisturebeingforcedoutoftheelements.The
terminalenclosurelidshouldbeleftopenduringthisperiodto
allowthemoisturetoescape.

Iftheheaterhasamanual‐resethighlimitthermostat,besure
thattheresetbuttonispressedin.

Ifreducedheatoutputissuspected,verifytheconditionofthe
heatingelementsbyusinganammetertocheckthecurrentdraw
ofeachinputline.Allinputlinesshoulddrawapproximately
equalcurrent,whichshouldagreewithnameplaterating.Ifthey
donot,oneormoreoftheheatingelementscouldbedamaged.

HAZARDOUSAREAS
(whereapplicable)
CAUTION
Troubleshootingandrepairsshouldonlybeattemptedby
qualifiedmaintenancepersonnel.
WARNING
Hazardousvoltagesarepresentinthisequipment.Lockout
andtagthebranchcircuitdisconnectswitchbeforeworking
onthisheater.
CAUTION
Troubleshootingandrepairshouldonlybeattemptedby
qualifiedmaintenancepersonnel.







PerArticle500‐516oftheNationalElectricalCode,ahazardous
areaisdefinedbya“Class”,“Division”,“Group”,and
“TemperatureCode”.TheClasscanbeIorII,whereClassI
indicatesthatthehazardclassificationisduetothepresenceof
anexplosivevapor.ClassIIindicatesanexplosivedust.The
Divisioncanbeeither1or2.Division1indicatesahazardis
WARNING – Explosion Hazard
HEATREXstronglyrecommendsinstallationbeperformedby
qualifiedpersonnelfamiliarwiththeNationalElectricalCode
andalllocalcodesandstandardsregardingexplosion‐proof
equipment.Itistheresponsibilityoftheinstallertoverifythe
safetyandsuitabilityoftheinstallation.

ALWAYSconsideredtobepresent.Division2meansthehazard
isonlypresentunderabnormalconditions.TheGroupdefines
theexplosivenessofthehazard.TheTemperatureCodespecifies
thetemperatureatwhichahazardwillignite.

HEATREXcanprovidedesignssuitableforalloftheabove
conditions,butaheatershouldneverbeplacedinan
environmentnotnotedontheheaternameplate.
NEVERoperatetheheaterinanatmospherewithanignition
codetemperatureLOWERTHANthenameplaterating.Theuser
mustdeterminetheactualareaclassification.
Specialdesignconsiderationsforelectricheatersusedin
hazardouslocations:
5
1. Locateallelectricalconnectionsinanappropriateenclosure.
2. Preventsurfacetemperaturesoftheheaterfromexceeding
thedesignignitiontemperature.
HEATREXPipeInsertHeatersdesignedforhazardouslocations
areprovidedwithanenclosuredesignedtocontainanexplosion.
Whenthedesigntemperatureoftheprocessexceedstherated
ignitiontemperature,itiscriticalthattheheaterandall
customerpipingisproperlyinsulated.
Ahazardousareaheatermustbepoweredandcontrolledbya
heatercontrolpaneldesignedtoprovidenecessaryover‐
temperaturesafetyinterlocks.ContactHEATREXifassistanceis
requiredtoproperlycontrolandprotecttheheater.
Neverapplypowertoaheaterinahazardousatmosphereunless
allterminalboxcoversareproperlyinstalledwithallcoverbolts.
Allconduitsenteringtheheaterterminalboxmustbesealed
within18”oftheheaterusinganexplosion‐proofconduitseal.
Anyunusedopeningsmustbeproperlysealedwithasteelpipe
plug.FollowtheNECforspecificconduitrequirementssuchas
therequirementforRigidConduit.

Toensureproperflamepath,allthreadedconduitsmustuse
ratedfittingsandbetight,withaminimumof5goodthreads
engaged.Anymachinedmetal‐to‐metalsurfacesonterminal
boxesmustbehandledcarefullytopreventscratcheswhichmay
voidtheexplosion‐proofrating.







Propergroundingofequipmentinhazardousareasiscriticalto
eliminatepotentialsourcesofsparking.

Replacementofelectricalcomponentsshouldonlybedoneby
authorizedpersonnelfamiliarwiththerequirementsof
maintainingelectricalequipmentinanexplosion‐hazardarea.






WARNING - Risk of Explosion
Operatingtheheateratavoltagehigherthanthe
nameplatevaluemayresultinelevatedtemperatures
andamperageabovethedesignratings.
HX79‐2150‐83‐1