Heatrex 797 SERIES Assembly instructions

INSTALLATION, OPERATING &

MAINTENANCE INSTRUCTIONS FOR 797 &

798 SERIES PIPE INSERT HEATERS



GENERAL



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.

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.



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



HandlingandStorage



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



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.



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

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.



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.



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.



WARNING

Surfacesoftheheaterpipeextendingbeyondtheuser’s

vesselmaybeextremelyhot.Avoidcontacttoprevent

ersonnelin

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.



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



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:

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

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