PROTECTS AND CONTROLS AGAINST…l

SCALEl

CORROSIONl

SILTl

ALGAE AND SLIME GROWTHl

CLOSED SYSTEM CORROSION

2008 Altom Ct. l St. Louis, MO 63146(314) 469-7000 l 1-800-554-5499

www.nucalgon.com

Cooling WaterTreatment

for theACR Serviceman

3-302

TABLE OF CONTENTS

• Introduction......................................................................................................................... Page3

• Terms................................................................................................................................... Page3

• Relationships....................................................................................................................... Page3

• CoolingWaterTreatment................................................................................................. Page4-8

1.WaterFundamentals..........................................................................................................Page4

2.ScaleFormationandControlofCyclesofConcentration................................................Page4

3.DeterminingMaximumAllowableCycles.......................................................................Page4

4.DeterminingAmountofBleedOffRequiredtoControlCycles......................................Page6

5.DeterminingtheAmountofChemicalRequired..............................................................Page7

6.CoolingTowerOperation.................................................................................................Page8

• ControllingBiologicalGrowths-AlgaeandSlime.............................................................. Page9

• CorrosionControl................................................................................................................ Page9

• WaterTesting.................................................................................................................... Page10

• AcidCleaning.................................................................................................................... Page11

• EquipmentforCoolingWaterTreatment.......................................................................... Page12

1.ConductivityMeters........................................................................................................Page12

2.ConductivityControllers.................................................................................................Page12

3.ChemicalFeedPumps.....................................................................................................Page13

4.Nu-CalgonEquipment.....................................................................................................Page13

• ClosedSystemTreatment.................................................................................................. Page13

• EvaporativeCoolers.......................................................................................................... Page14

• SampleFieldReport.......................................................................................................... Page15

• ProductListing.................................................................................................................. Page16

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Priortothediscussionofwatertreatmentasitpertainstotheairconditioningandrefrigerationindustry,let’smakeoneobservation:Ifyoucanunderstandwhywatertreatmentisnecessaryandwhatproblemsarecausedbythelackofit,thetaskitselfbecomes,generally,quitesimple.

Therearebasically threeoptions forproviding theproperwater treatment.1)Contractawater treatment servicecompanytocomeinanddoit,2)Contractanairconditioning-refrigerationservicecompanytocomeinanddoitor,3)Doityourself.Ifthefirstoptionischosen,thereliabilityoftheequipmentisatthemercyofthepersondoingthewatertreatmentandnotinthehandsofthepersonresponsiblefortheequipment.Obviously,it’sbestthatthepersonresponsibleforthemechanicalsideofasystemalsoberesponsibleforthewatersideaswell.

Thismanualwaswritten toassistyou, theserviceman, inprovidinganapprovedandacceptablewater treatmentprogramthatwillassurethattheequipmentoperatesaswellaspossible.

Accordingly,therearesometermsandrelationshipsthatyouneedtobecomefamiliarwith.Thefollowingisalistofthesetermsandrelationshipsandadefinitionofeach.

1. ppm—partspermillion(howmanypoundsofasubstancethereareinamillionpoundsofwater).Mayalsobeexpressedasmg/1(milligramsperliter).

2. gpg—grainspergallon(measurementofwaterhardness).Mayalsobeexpressedinppm(seebelow).3. gpm—gallonsperminute(measurementofwaterflow).4. gph—gallonsperhour(measurementofwaterflow).5. BTUh—BritishThermalUnitsperhour(measurementofheat).6. Ton—coolingeffectofremoving12,000btu’sofheat.7. TDS—totaldissolvedsolids(thetotalamountofdissolvedmineralspresentinthewater).8. µmhos—micromhos;unitofmeasureofconductivity(theoppositeofohmwhichistheunitofmeasurefor

resistance).Usedasanindirectmeasureoftotaldissolvedsolids(TDS).9. COC—cycles of concentration; refers to the number of times the TDS of themakeup (fresh)water has

concentratedintherecirculating(tower)water.10.∆t—chanceintemperature;usedtodiscussthedifferenceintemperaturebetweenwatercomingfromthe

towerandwaterreturningtothetower.

1. 1gpg=17.1ppm2. 1gallonofH

2O=8.34lbs.

3. 1ppm≈1mg/1(milligramperliter)4. 1ft3H

2O=7.5gallons

5. TDS=µmhosx.756. µmhos=TDSx4/37. Btu/h=500xRecirc.Rategpmx∆T

ANDONEMORE—a ton of refrigerationwill remove 12,000Btu’s of heat per hour but the cooling tower orevaporativecondensermustremove15,000Btu’sofheatperhourduetotheextraheatpickedupfromthecompressor,generallyacceptedtobe3,000Btu’s.Thisisveryimportanttoremember.

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COOLING WATER TREATMENT

1. WATER FUNDAMENTALS Thehydrologiccycleistheongoingprocessofevaporationandprecipitationinthecourseofwatermovement.Aswaterevaporatesfromtheearth’ssurface,itdoessoinapurestate.Asitfallsbacktoearthintheformofprecipitation,itpicksupcontaminatesfromtheair.Asitpercolatesdownthroughtheearth’slayersandflowsacrosstheearth’ssurface,itdissolvesandpicksupmanydifferenttypesofminerals.Infact,waterisgenerallyregardedasauniversalsolventandifgivenenoughtimewilleventuallydissolvepracticallyanything.

Thesedissolvedmineralsarethecauseofmostoftheproblemsassociatedwithwater-cooledequipment(ie.coolingtowers and evaporative condensers).As thewater containing all of thesedissolvedminerals (calledTotalDissolvedSolidsorTDS)iscirculatedthroughacoolingtowerorevaporativecondenser(anOpenRecirculatingCoolingWaterSystem,orORCWS),asmallportionofitisevaporated(approximately1.8gphpertonor0.03gpmperton)toremovetheheatthatisabsorbedfromtherefrigerant.Inthisway,therestoftherecirculatingwateriscooledandmaybereusedtopickupheatinthecoolingapplication(commercialairconditioning,processcooling,etc.).TheevaporatedwateristhenreplacedwithfreshmakeupwaterwhichcontainsmoreTDS,allowingtheconcentrationofmineralstoincrease.

2. SCALE FORMATION AND CONTROL . . . CYCLES OF CONCENTRATION Ifyouwillrecall,waterevaporatesinapurestate.AswaterisevaporatedfromanORCWS,itsmineralcontentisleftbehind.Asthisevaporatedwaterisreplaced,itisdonewithfreshmake-upthatcontainsmorenaturallyoccurringminerals.Ifleftunchecked,themineralcontentwillcontinuetogrowandeventuallyexceedthewater’ssaturationpointandbeginto“fall-out”(precipitate)asscale.Themostcommontypeofscaleiscalciumcarbonateor“limescale”.Othertypesofscalearecalciumsulfate,magnesiumsulfate,silica,etc.

This build-up or concentration of minerals in the recirculating water is referred to as Cycles of Concentration(abbreviatedCOC or just C), and it represents the number of times theminerals present in themake-upwater areconcentratingintherecirculatingwater.

TomaintaintheCyclesofConcentrationorCatasafelevelinanORCWS,ableed-offisused.Bleed-offisthepurposefulremovalordraining,toanapproveddrain,ofasmallamountoftherecirculatingwater.Thebleed-offshouldbetakenfromaspotlocatedafterthecondenser.Thislossofrecirculatingwatercausesanequalamountoffreshmake-upwatertobeintroducedintothesystemwhich,ineffect,dilutesthemineralcontentoftherecirculatingwater,reducingtheCOCorTDSlevel.AndinordertoallowthewatertomaintainthehighestamountofsolubleTDSwithoutscaleformation, chemicals are added.Essentially, the use of selected chemicals gives thewater a higher saturationpoint.Thetypeofchemicalusedandthequalityofthemake-upwateriswhatdeterminesthelevelofCOCthatcanbesafelymaintainedinanygivensystem.

3. DETERMINING MAXIMUM ALLOWABLE CYCLES OneofthemostimportantstepsinwatertreatmentforORCWSisdeterminingthemaximumlevelthattheTDSwillbeallowedtoconcentrate,orthemaximumallowablecyclesorCOC.Thisdeterminationisdirectlycontrolledbythetotalalkalinity,hardnessandsilicaofthemake-upwater(toamuchlesserdegree,chloridescanbeanissueiftheyareunusuallyhighinthemake-upwater).And,inthecaseofthealkalinity,thetreatmentproductselectedalsoplaysarole.

Oneofthemostimportantcharacteristicsofwaterisitsalkalinity.Themineralsthatbelongtothealkalinityfamilyarecarbonates(CO3),bicarbonates(HCO3)andhydroxides(OH).Thesethree,takentogether,arereferredtoastotalalkalinity,andthetotalalkalinityofthemake-upwaterwilldeterminewhattypeofproblem(scaleorcorrosion)toexpect.Generally,thetotalalkalinityoftherecirculatingwatercannotexceed420-600ppmdependingupontheproductselected.

–4–

Withmake-upwaterhavinglowalkalinitylevels(below30ppm),corrosionistheanticipatedproblemandaproductcalledCal-Treat233shouldbeused.Formake-upalkalinitylevelsbetween30ppmand60ppm,wewouldexpectlightscaletobetheproblemencountered.However,itisalsopossibletohaveacorrosionproblem.Therefore,theproducttousewouldagainbeCal-Treat233asitisalsoagoodscaleinhibitoraswellasagoodcorrosioninhibitor.WhenusingCal-Treat233,thetotalalkalinitylevelcannotexceed500ppmintherecirculatingwater.

Formake-upalkalinitylevelsabove60ppm,scaleistheexpectedproblemandeitherNo.340LiquidScaleInhibitororTy-IonC70canbeused.No.340LSIisstrictlyascaleinhibitorwhileTy-IonC70inhibitsbothscaleandcorrosion,anditdispersessilt.Onceagain,therearemaximumallowablealkalinitylevelsfortherecirculatingwaterwhenusingtheseproductsandtheyare480ppmand600ppm,respectively.

Regardless ofwhichproduct is selected, themaximumallowableCOCaccording to alkalinity is determinedbydividingthealkalinityofthemake-upwaterintothemaximumallowablealkalinitylevelfortheparticularproductbeingused.Forexample:ifTy-IonC70isbeingusedandthetotalalkalinityofthemake-upwater(abbreviatedmu/alkandmeasurablewithasimpletitrationtypetest)is180ppm,thenyouwoulddivide600by180andarriveatananswerof3.3allowedcycles(byalkalinity)forthatsystemwhenusingTy-IonC70.

But,anotherimportantcharacteristicofwaterishardness.Themineralsthatbelongtothehardnessfamilyarecalcium(Ca)andmagnesium(Mg).Bothoftheseminerals,takentogether,arereferredtoastotalhardness,andtotalhardnessalsoplaysanimportantroleindeterminingthemaximumallowablecyclesofconcentration.Thesignificanceofthehardnessisthattheycombinewiththealkalinityand/orsulfatemineralstoformmosttypesofscaledepositsfoundinORCWS.Themaximumlevelofhardnessmineralsthatcanbesafelymaintainedinsolutionintherecirculatingwateris1000ppm,regardlessoftheproductused.MaximumallowableCOCaccordingtohardness,then,isdeterminedbydividing1000bythetotalhardnessofthemake-upwater.

Silicaisalsoveryimportant.Silicaiswhatglassismadefrom.Silicascale,causedbyanexcessiveamountofsilicaintherecirculatingwater,must be avoidedasitcannotberemovedbyacceptableaciddescalingmethodsthatareeffectiveontheothertypesofscales(seeapplicationbulletin3-106forinformationaboutacidcleaning).Thesilicalevelintherecirculatingwatercannotexceed150ppm,onceagainregardlessoftheproductbeingused.MaximumallowableCOCaccordingtosilica,then,isdeterminedbydividing150bythetotalsilicaofthemake-upwater.

Regardlessofthemake-upalkalinity,hardnessorsilica,themaximumcyclesofconcentration(COC)shouldneverexceed8.0.

SUMMARY

Onceyouhaveselectedtheproducttouse,alwaysusethesmallestnumberobtainedfromtheabovecalculationsforthatproduct.ThatsmallestnumbermustbethemaximumlevelofallowableCOC.

Whenusing Cal-Treat 233 No. 340 LSI Ty-Ion C70

Maximumallowable 500 480 600COCbyalkalinity mu/alk mu/alk mu/alk

Maximumallowable 150 150 150COCbysilica mu/SiO2 mu/SiO2 mu/SiO2

Maximumallowable 1000 1000 1000COCbyhardness mu/H mu/H mu/H

–5–

4. DETERMINING AMOUNT OF BLEED-OFF REQUIRED TO CONTROL CYCLES Theamountofbleed-offrequiredisdeterminedbythecycleswearetryingtomaintainandthecapacity(tonnage)ofthesystem.Obviously,asystemthatcanoperateat4.3cycleswouldrequirelessbleed-offthanonethatoperatesat3.3cycles,assumingequalcapacity.Withthedesiredcyclesknown,theamountofbleed-offcanbecalculatedfromthefollowingformula:

B=––––,whereC=COC E=evaporationrate B=requiredbleed-off

Asapointofinformation,theevaporationrateisgiventobe1.8gph/tonor0.03gpm/ton.Andforthosemost interested,thisisderivedfromthefactsthat: a.15,000BTUhmustbedissipated b.thereare970BTUhdissipatedforeverypoundofwaterevaporated,and c.waterweighs8.34lbs./gal.

Therefore:

–––––––÷8.34=1.8gph/ton,oringpmitis0.03pgm/ton.

Inanyevent,factorintheevaporationandthetonnage,andthecalculationforbleedbecomes:

Bleedingpm(Bgpm)=––––(tonnage)

Allthatisneeded,then,tocalculatetheamountofbleed-offrequired,istoknowthemaximumlevelofCOCallowedandthetonnageofthesystem.Andyouwillrecall,inordertofindCOCyoualsomustknowwhichchemicalisgoingtobeusedaswellasthealkalinity,hardnessandsilicalevelsofthemake-upwater.Let’slookatanexample: Example: 1.Chemicalselected=Ty-IonC70 2.Make-upalkalinity=140ppm 3.Make-upsilica=22ppm 4.Make-uphardness=200ppm 5.Capacity=120tons COC by alk. COC by Silica COC by hardness

––––=4.3 ––––=6.8 ––––=5.0

therefore,COC=4.3(thesmallestofthethree).

Tocalculatebleed-offingpm(abbreviatedBgpm):

Bgpm=––––(120)=––––(120)=1.09gpm,or1gpm.

Onceitisdetermined,thebleedcanbesettofunction,either(1)atalltimesthesystemisrunningor,andthisismorepreferrable,(2)itcanbecontrolledwithaconductivitymonitorcontrollerandsolenoidvalve,(automaticbleed&feedsystem),suchastheCMS-IVCoolingMonitorSystem.

EC-1

.03C-1

600140

15022

1000200

.034.3-1

.033.3

15,000970

–6–

Cyclesofconcentrationvs.bleed-off.Wecanseefromthebleed-offformulathattheCOCandthebleed-offareinverselyproportional.Asthebleed-off is increased, theCyclesofConcentrationwilldecrease,andviceversa.Lookingat thefollowingchartyoucanseethatastherequiredCOCisincreasedfrom1.5to2andfrom2to3,therequiredbleed-offdecreaseseachtimeby50%.Itdecreases33%from3to4and25%from4to5andsoon.Thegreatestwatersavingsoccuruptoabout5or6COC.

Therearetwomethodsofdeterminingtheamountofchemicalrequired:aspecific,moreexactingwaythatwewillshowyoubelowandasimplifiedmethod.

Doingitthespecificway,wewouldlookattheformulausedtocalculatethemonthlychemicalfeedrequirement:

#’s=––––––––

Where: 1.#’s=lbs.ofchemical/1000gal.ofmake-up/day 2.ppm=partspermillionofchemicaldesired 3.C=maximumallowablecyclesorCOC

First,calculategal/dayofmake-up: make-up=(bleedover24hours)+(evaporationover24hours),or make-up=(Bgpmx60x24)+(1.8x24xtonnage) Therefore: #’s/day=––––––––x–––––––––––––or––––––––x–––––––––––––––––––––––––––

Onceyouknowpoundsperdayofrequiredproduct,youneedtochangeittogallonsperdayandultimatelygallonspermonth: gallons/month =––––––––––––––––––––(30)

EXAMPLE: 1.System=100tons 4.mu/alk=160ppm 2.Chemical=C70@50ppm 5.COC=3.75 3.Productwt./gal.=9.6 6.Bleed-off=1gpm

C70=––––––––––––––––––––––––––––––––––––––––––––––––––––– (calculationcontinuedonPage8)

COC Bleedgph/ton Bleedgpm/ton Change

10 .20 .0033 13% 9 .23 .0038 13% 8 .25 .0043 14% 7 .30 .0050 17% 6 .36 .0060 20% 5 .45 .0075 25% 4 .60 .0100 33% 3 .90 .0150 50% 2 1.8 .0300 50% 1.5 3.6 .0600

ppm

(120)(C)

(#’s/day)product’swt./gal.

ppm(120)(C)

ppm(120)(C)

(Bx60x24)+(1.8x24xtonnage)1000

dailymake-up1000( ) ) ) )( ((

9.6

ppm(120)(C)

(Bx60x24)+(1.8x24xtonnage)1000( ) )( 30 )(

–7–

C70=–––––––––––––––––––––––––––––––––––––––––––––––––––––

––––––––––––=––––––=1.8gals/month

TheSimplifiedWay

There isaneasierway!While thispreviousmethod iscorrect, it ismostexacting. Asa result,wehaveamoresimplifiedmethod that results inasimilaranswerwithoutall thearithmetic. It isassimpleas this:The amount of monthly chemical feed for a particular Nu-Calgon product is calculated by multiplying the Bleed-off in gpm times that product’s special factor!Nu-CalgonNo.340LiquidScaleInhibitormustbefedat10-15ppm,Cal-Treat233mustbefedat200-300ppmandTy-IonC70mustbefedat45-50ppmforscaleandsiltcontrolandat120-150ppmforscale,siltandcorrosioncontrol.Toobtaintheproperamountofmonthlychemicalfeed,usethefollowingchart:

EXAMPLE:usingTy-IonC70andthepreviousexample,a) 1gpmofbleed-offisrequired.b)Therefore,forscaleandsiltcontrol,youmultiplythebleedingpmtimesC70’sfactor,or1x2=2gallons.ofC70

neededtotreatthesystemat100%loadconditionsforthewholemonth.c)For corrosion and silt control, youhave1x6, or6gallonsofC70needed to treat the systemat100% load

conditionsforawholemonth.

ChemicaltreatmentcanbefedwithNu-CalgoncalibrateddripfeedersorwithaconductivitymonitorcontrollerandachemicalfeedpumpsuchastheCMS-IVCoolingMonitorSystem.And,inordertochecktheamountofchemicalpresentintherecirculatingwater,usetheNu-CalgonOrganicPhosphorusTestKit(4804-0)ortheNo.89ATestKit(4798-2).

6.COOLINGTOWEROPERATION Theproperoperationofthecoolingtoweritselfisofgreatimportanceintheoveralltaskofwatertreatment.Thewaterdistributionholes,spraynozzles,fillandbasinmustbekeptingoodconditiontoinsureproperwatermovementandsystemoperation.Averyimportantpartoftheproperoperationofacoolingtowerorevaporativecondenseristhemake-upwaterfloatassembly.Unlessthisissetproperly,itisimpossibletoprovideproperwatertreatmentforthesystem.

Inordertosetthefloatsoastooperateproperly,pleasefollowtheseguidelines:1. Withthesystemnotrunning,adjustthewaterlevelsothatitisapproximately1”-2”belowtheoverflow.

2. Adjustthefloatsothatnomake-upwaterisallowedtoenterintothesumpwhenthecirculatingpumpfirstcomesonandthewaterleveldrops.

3. Insurethataftersettingthefloattoaccomplishthis,anyfurtherdropinthewaterlevelwillresultintheadditionofmakeupwaterintothesump.

.1x5.76x309.6

17.259.6

9.6

50450

(1x60x24)+(1.8x24x1001000( ) )( 30 )(

Chemical ppmdesired Factor

No.340L.S.I. 15 .5

Ty-IonC70 50 2

Ty-IonC70 150 6

Cal-Treat233 250 10

–8–

Theaboveguidelinesarepresentedtoinsurethatwaterremovedfromthesumpatsystemstart-upisnotreplacedbymake-upwater.Theonlytimemake-upwaterneedstobeaddedtothesumpiswhenwaterislostduetoevaporationorbleed-off.Ifwaterisallowedtorefillthesumpduetotheinitialdropinwaterlevelatstart-up,whenthesystemisshutdowntherewillbeanexcessamountofwaterinthesump,resultinginwaterlossviatheoverflow.Whenthisoccursanunknownamountofchemicalislostandisnotreplaced.Also,TDSislostcausingadropinCOCandconductivity.IfthisisallowedtooccurrepeatedlythefinebalanceofTDSandchemicalresidualwillbelostanditwillbeimpossibletomaintianaproperwatertreatmentprogram.

Itisveryimportanttorealizethefactthattheonlywaterthatshouldbeallowedtoleavethesystemisfrombleed-offand/orevaporation.Anywaterthatisallowedtogoouttheoverflowwillthrowoffthebalanceofchemicalthatmustbemaintainedatalltimes.

DO NOT FORGET THAT THE AMOUNT OF WATER LEAVING THE SYSTEM MUST BE KNOWN IN ORDER TO BE ABLE TO ACCURATELY MAINTAIN THE PROPER AMOUNT OF CHEMICAL IN THE WATER!!

Ifthisfactisoverlooked,thetaskofwatertreatmentbecomespureguesswork.Onpage15,thereisasamplereportthatmaybeusedinthefieldtokeeparecordofwatertreatmenttestresults.Itcanbepersonalizedbycopyingitontoyourletterhead.

CONTROLLING BIOLOGICAL GROWTHS—ALGAE AND SLIME Allwatercooledequipmentissusceptibletoalgaeand/orslimebacteriainfestationsincebacteriaispresentinthewatersuppliesandtheatmosphere.Ifacoolingtowerorevaporativecondenserisinfectedwitheitheralgae(avegetablegrowth)orslime(ananimalgrowth),itmustbetreatedwithanalgaecide(biocide).Thealgaecideorbiocidekillstheproblem-causingmicrobials and prevents the infestation from causing anymajor problems.Normally if a system istreatedwith an approved and effective biocide, the algae and slime growths are controlled. Sometimes, however, aparticularstrainofbacteriaisabletodevelopanimmunitytothebiocidebeingused.Ifthishappens,allthatneedstobedoneistotemporarilyswitchbiocides.Sometimes(thoughrarely)itmayevenrequiretwodifferentbiocidesbeingusedatthesametimetocontrolanextremelyhardystrain.

Tocontrolalgaeandslimegrowthsonacontinuousbasis;(a)feedNu-CalgonNo.85Algaecideintothesystemattherateof1/6gal/monthforevery50gphofbleed-offusingoneofNu-CalgonDripFeedersor(b)feedNo.90Algaecideattherateof1-1.5lbs./monthforevery1.0gpmofbleed-offusingoneofourBrominefeeders,ameshfeedbagorabiocidefloater.Thesetwoproductsmaybeusedindependentlyortogether,beingalternatedasrequired.ThebestresultsareobtainedbyusingNo.90Algaecide.

CORROSION CONTROL Corrosionisthe“eatingaway”ofthesystemmetalsandcanoccurinoneoftwoways.

1. “GeneralAttack”typecorrosionisuniforminitsappearanceasitattacksallmetalsexposedtothewaterinafairlyuniformmanner.This typeofcorrosionis the leastaggressiveof thetwoandisgenerallycausedbythewaterhavingalowpHoralargeamountofdissolvedcarbondioxidepresentinit.Inthelattercase,carbonicacidisformedresultinginalowpHconditionandcorrosion. 2. “Pitting”typecorrosionappearsasscatteredorlocalizedpits.Thisiscausedbyoxygenmoleculesbeingtrappedundersomethingthatisadheringtothemetalsuchasscale,siltorbiologicalgrowths.Asoxygenisaverycorrosiveelement,thisresultsinholesbeing“eaten”clearthroughthemetal.Thistypeofcorrosionismuchmoreaggressiveandthereforemuchfasterthanthegeneralattacktypediscussedabove.

–9–

Tohelppreventcorrosionfromoccurring,corrosioninhibitorsareusedtocoatthesystemmetalswithaprotectivefilmtopreventthemetalfrombeingattacked.Thisismosteffectivewhentheinhibitorisusedfromthe“firstday”ofthesystem’soperation.Ifthesystemisallowedtooperatewithoutanycorrosioninhibitorsinthewater,corrosionwillstart.Itisverydifficulttocorrectthisproblemasalloftheexistingcorrosionby-productsmustberemovedpriortothestartofanytreatmentbyaninhibitor.Ifthecorrosionby-productsarenotremovedandtheinhibitorsaredepositedontop,thecorrosionwillcontinueunderneaththeinhibitorsandtheywillnotbeeffective.Inhibitorshowever,willhelpcorrosionfromstartinginanynewareas.

Averycosteffectivewayof removingexistingcorrosionproducts isbyusingagoodhydrochloricacidsuchasNu-Calgon’sLiquid Scale Dissolver.Tousethisproduct,followthedirectionsfoundinproductbulletinNo.3-106.

Nu-Calgon has several very good products available for use as a corrosion inhibitor. Each has its own specialapplicationandareawhereitisalittlebetterthantheothers.

1. Cal-Treat233isazinc,molybdateandorganicphosphonatebasedproductusedprimarilyinverylowalkaline waters.Italsocontainsacoppercorrosioninhibitor. 2. Ty-IonC70isanorganicphosphonateandpolymerbasedproductthatalsoincludesacoppercorrosion inhibitor. 3. Micromet,whichcomesinbothaplate(SeasonTreat)andcrystalform,isaninorganicpolyphosphateproduct withover50yearsofsuccessincontrollingcorrosion.Itisusedinmoderatelyalkalinewaterswherethewater canbeeithercorrosiveorscaleforming.

WATER TESTING The No.89A Test Kit has all of the materials necessary to run the tests that are appropriate for cooling waterapplications:alkalinity,hardness,chloridesandpHaswellasproductresidualtestsfororganicphosphorousandsodiumnitrite(silicaisnotincluded)..Wehavealreadydiscussedalkalinityandhardnessandtheimportantroletheyplaybothinpredicting theproblemtoexpectand insettingupaproperpreventativemaintenanceprogram.Now, let’sdiscusschloridesandpH.

1. CHLORIDES Chlorides(CI)areoneof themanymineralspresent inwater.Theyareverysoluble inwater,meaning theycanconcentratemany,manytimeswithoutprecipitating.Forthisreasontheyareusedasacomparisonorbarometeragainsttheothermineralconcentrationstomakesomedecisionsastowhatisgoingoninsidetherecirculatingwaterregardingtheconcentrationsofminerals(COC).

Thenormalprocedureistomeasurethealkalinity,hardness,chloridesandpHandsilicaofthemake-upwaterandalsooftherecirculatingwater.Dividemake-upalkalinityintorecirculatingalkalinityandyou’llarriveataCOCforthealkalinityminerals.Dothesameforthehardness,silicaandchlorideminerals.Ifthesystemisoperatingasitshould(inbalance),thealkalinity,hardness,silicaandchloridemineralsshouldallbeconcentratingataboutthesamerate.Ashasalreadybeendiscussed,scaleisformedbymineralsprecipitatingandformingdeposits.Ifthealkalinity,hardnessandsilicamineralshaveprecipitatedandformedscaledepositswithinthesystem(condenser,piping,tower,etc.),thentheynolongerwillbepresentintherecirculatingwatertobemeasuredwiththetestkit.Ifthatisthecase,therewillbealowerCOCforthem,particularlyhardness,thanforchlorides.Wewillthenhaveacluethatsomethingisnotasitshouldbeandtheproblemshouldbelookedinto.IfahigherCOCforalkalinity,hardnessandsilicathanforchloridesispresent,thenmineralsthathadbeendepositedpreviouslyarebeingremovedfromsomewhereinthesystemandplacedinsolutioninthewater,andthatisgood....descalingistakingplace.

–10–

EXAMPLE IN BALANCE Make-up Recirc COC alkalinity 120 530 4.4 hardness 225 990 4.4 pH 8.1 8.8 chlorides 55 240 4.4 conductivity 550 2400 4.4

SCALING alkalinity 120 430 3.6 hardness 225 810 3.6 pH 8.1 8.7 chlorides 55 240 4.4 conductivity 550 2150 3.9

DESCALING alkalinity 120 625 5.2 hardness 225 1170 5.2 pH 8.1 9.0 chlorides 55 240 4.4 conductivity 550 2750 5.0

Asyoucansee,inaproperlybalancedsystem,thealkalinityandhardnessmineralsmustconcentrateatavalueequaltoorgreaterthanthatofthechlorides.Ifthisisnotthecasethenscaleisbeingformedandtheoperatingparametersmustberecalculatedandrechecked.Thistestingandanalyzingmustbedonemonthlytoensureproperoperation.

2. pH pHisthetermusedtoexpresstheacidityoralkalinitylevel,orstrength,ofasubstance,anditisrepresentedbyanumber.ThepHscaleisalogarithmicscalefromzerotofourteenwithsevenbeingneutral.Asubstance,suchaswater,havingapHbelowsevenisacidic.Ifitsvaluewereabovesevenitwouldbealkaline.WaterwithalowpH(say,6.8orlower)oranalkalinitylevelbelow30ppmshouldbeconsideredaspotentiallycorrosiveandtreatedwithacorrosioninhibitor.Asthealkalinityoftherecirculatingwaterincreasesorbecomesmorealkaline,thepHwillalsoincrease.ThepHoftherecirculatingwaterwillusuallybegreaterthanthemake-upwaterpHbecause,asalkalinityincreases,soshouldthepH.

ACID CLEANING

Acidcleaningisperformedtoremovescaledepositsandcorrosiondepositsfromwatercooledequipment.Therearemanydifferentacidsthatcanbeusedtoaccomplishthistask,however,thetwomostcommononesarehydrochloricandsulfamicbecauseofthereefficiencyandrelativesafety.

Whencorrosiontakesplacewithinthesystem,theintegrityofthesystemmetaliscompromised,whichresultsindrasticallyreducedequipmentlifeandtheformationofcorrosiondepositsoccurs.Thepresenceofscaleorcorrosiondepositswillreduce water flow and heat transferwithin thesystemwhichresults in lossofsystemefficiencyandhigheroperatingcosts. When thisoccurs in air conditioningor refrigeration systems it causes the systemoperatingpressuresand temperatures to increase. These increases result inmore rapidbreakdownof thecompressor lubricantcausinglossoflubricationandcompressorfailure.

Tolearnaboutthesetwoacidsandtheproperproceduresforusingthem,refertoourApplicationBulletinNumber3-106“RemovingScaleFromCoolingTowerSystems”.

–11–

EQUIPMENT FOR COOLING WATER TREATMENT1. Conductivity Meters

The conductivity meter is a hand held instrument that is used to measure the conductivity or TDS of water.Conductivitymetersareusuallycalibratedinµmhosbutsometimestheyarecalibratedinppm.Theconductivitymeterisoneofthetoolsofthewatertreatmentspecialist.ItprovidesaveryfastwayofdeterminingtheCOCofasystem.ItisalsousedtocalibrateconductivitymonitorcontrollersliketheCMS-IVbyfirstcalibratingthemeterwithCalibrationSolutionandthenusingittocalibratethecontroller.

2. Conductivity Controllers

There aremanymakes andmodels of conductivity controllers ormonitors in use today.However, they are alldesignedtodothesamething:continuouslymonitortheconductivity(TDS)oftherecirculatingwaterandtoturnonableed-offsolenoidvalveandachemicalfeedpumpwhentheconductivityreachesapredeterminedsetpoint.

The controller utilizes a sensor that is installed in the recirculating loop as themeans ofmonitoring the waterconductivity.Whentheinputfromthesensorreachesthesetpointofthecontroller,tworelaysareenergized.Oneoftherelayssuppliespowertothebleed-offsolenoidvalveandtheotheronesuppliespowertothechemicalfeedpump.Thenormallyclosedbleed-offsolenoidvalveopensandallowsapresetrateofrecirculatingwatertobedischarged(bledoff)intoanapproveddrain,causinganequalamountoffreshmake-upwatertobeintroducedintotherecirculatingwater;sincethemake-upcominginhasalowerTDSthanthebleed-off that it isreplacing, thesystem’sTDSisessentiallydilutedorreducedandCOCis thuscontrolled.Thechemicalfeedpumpispreset topumpasetamountofchemicalintothesystemduringthesameperiodoftimethatthesystemisbleeding-off;essentially,thisreplaceschemicalthatislostthroughbleed.Withapredeterminedandpresetamountof“bleed-off”andchemicalfeed,theCOCandtheproperamountofchemicalresidualsareconstantlyandautomaticallycontrolled.

Somecontrollersutilizea“setknob”toallowforsettingofthe“setpoint”.Themoresophisticatedandbetteronesutilizeananalogmeteroradigitalread-outwhichallowsforacontinuous,visualindicationofthewaterconductivity.Andthetop-of-thelineunits,liketheCMS-IV,aredigital.

Thecontrollersshouldbeequippedwithmeansofcalibratingthemforproperoperation.Theproperprocedureistouseapre-calibrated,handheldconductivitymetertomeasuretheconductivityoftherecirculatingwaterandthentocalibratethecontrollertoreadthesameasthehandheldmeter.

Thebettercontrollersalsohavea“safetylock-outtimer”toautomaticallyturnoffthechemicalfeedpumpif theoperatingor running timeof thepumpexceeds the time seton the “lock-out timer”.This isdone toprotect againstaccidentallypumpingout theentirecontainerofchemical in theeventofa failurewithin the system thatallows thecontrollertostayinacontinuous“run”modeforanextendedperiodoftime.Wheneveracontrollerisequippedwitha“lock-outtimer”,itshouldbesetat60-90minutes.Andifthesystemeverrunsatclosetooratfullloadformostoftheoperatingtime,itisagoodideatoincreasethebleedrate,perhaps25%abovethenormallycalculatedrate.ThiswillprovideforaquickerreductioninsystemTDSandpreventthesystemfrom“floating”nearthe“setpoint”.Itwillalsopreventthe“lock-outtimer”fromprematurelyturningoffthechemicalfeedpump.Ifthisisdone,increasethecalculatedmonthlyrateofchemicalfeedby25%aswell.Conductivity Controllers should be calibrated and have their sensors cleaned monthly.

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Therearemanytypesandstylesoffeedpumpsavailableandinuse.However,themostaccurateandreliableoneshavetwocontrolsonthem.Oneofthemistoadjustthe“stroke”oractualdistanceofthediaphragmmovementandtheotheroneistoadjustthe“speed”orfrequencyofthismovement.Mostpumpsareratedingpd(gallonsperday)output,and this information isusuallyprintedon thepumpnameplate.Toproperly setupapump, theamountof chemicalfeedrequiredpermonthmustbeknownandthisfigureisthenconvertedtoapercentageofthepump’stotalmonthlyoutputcapacity.Thepercentageofspeedoperationmultipliedbythepercentageofstrokeoperationmustthenequalthispercentageofthepump’stotalcapacity.

EXAMPLE: 4gpdpump=120gal/month 2.5gal/monthchemicalneeded

Therefore,weneed: 2.5gal/monthchemicalfeedrate,whichis0.02or2%ofthepump’smaximumcapacity.

Toobtain2%ofthepumpoutput,multiplyadecimalstrokesettingbyadecimalspeedsettingtoobtain.02.Forexample,10%speed(.10)x20%stroke(.20)=.1x.2=.02.Setthespeedcontrolat10%andthestrokecontrolat20%.Thiswillgiveyou2%ofthepumpoutput,or2.5gal/month.Whenthegpdoutputofthepumpissolargethatthedesiredsettingscannotbeobtained,apercentagetimersuchastheC-1120maybeused.

4.Nu-CalgonEquipment Nu-Calgonprovidestwopiecesoffeedequipment.ThefirstistheCMSFeedPump.Itcanfeedupto15.1gallonsperdayandaslowas0.02gallonsperday.Ithasbothfrequencyandstrokeadjustments.TheotheristheCMS-IVPump/Monitor,adigitalunitthatcombinesboththepumpandtheTDSMonitorintooneunit.Itisaveryadvancedpieceofequipment,combiningapumpoutputof0.02–15.1gallonsperdayandvariousfeedtimerarrangements. Experiencehastaughtusthatclosedsystems(ie.chilledwaterloops,hotwaterloopsandprocesswaterloops)mustbetreatedforthepreventionofcorrosion.Itisgenerallyacceptedthatthebesttreatmenttouseinclosedsystemsisaborax-nitritetypeproduct,andNu-Calgonhassuchaproductavailable.Itisared-coloredliquidcalledTy-IonB20anditofferstheeaseoftreatmentleveldetectionbyasimplecolorcomparison,bytheabilitytoadministerthechemicalthroughalmostanyavailableopeningandbyapolymerdispersantformudandsludgedispersing.

Ifthesystemtobetreatedisnoticeablyfouled,thoroughlyflushthesystemasmuchaspossibleandaddfreshwater.Ifapotfeederisnotalreadyinplaceforintroducingtreatment,installaNo.44PotFeederonaby-passarrangement.Ifyouhavechosentousetheliquid,anypluggedopeningcanbeusedforthispurpose.Ifthereisahosebibavailable,aT775-0SilverKingPumpmaybeused.Therealbenefitofthispumpisthatitcanbeusedcontinuallyonalljobs.

Ifthesystemwasflushedduetofouling,asaninitialcharge,add3gallonsofTy-IonB20liquidforevery100gallonsofwaterinthesystem.Thiswillprovideanexcessoftreatmenttoreactwithanyexistingcorrosionproducts(ironoxide)inthesystem.Ifthesystem’swaterturnsmurkyordirtywithin4-6weeksduetothetreatment’sreactionwtihtheironoxidedepositsinthesystem,thewatershouldbedrainedandflushedtopreventanyproblemsthatcouldbecausedbylooseneddeposits.Ifyouflushthesystemafter4-6weeks,besuretoaddfreshwaterand1gallonofTy-IonB20forevery100gallonsofwaterinthesystem.Thiswillprovidetherequiredtreatmentlevelof1000-1200parts

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permillion(ppm)ofsodiumnitrite.Thistreatmentlevelisalsotherequireddosageforanewsystemoronethatisnotnoticeablyfouled.

Note that the 1000-1200 ppm treatment level must be maintained at all times if proper protection is to be assured. And if the system is a hot water boiler where the temperature is above 180°F, it may be necessary to use up to 1800 ppm as nitrite.

Nu-Calgon’sW003-0TestKit(orthetheNo.89ATestKit)isanidealwaytomeasuretheamountofsodiumnitriteinthewater.Thetestshouldbeusedtocheckthetreatmentleveleverymonthaswellasduringtheinitialtreatmentofthesystem.AhandheldConductivityMeter(Part#4812-0)maybeusedinlieuofthetestkit,incaseofanemergency,byfirstmeasuringtheconductivityoftherecirculatingwaterandthenaddingchemicaluntiltheconductivityofthesystem’swaterincreasesbyapproximately1400-1600µmhos.

Oncethesystemiscleanedup,orifitisanewsystem,andadropintreatmentlevelinnoticed,itishighlyprobablethataleakexistswherewaterisleavingthesystem.Thesystemshouldbeinspectedthoroughlyinordertomaintainthe1000-1200ppmtreatmentlevelatalltimes.

EVAPORATIVE COOLERS

Evaporativecoolers,or“swampcoolers”astheyareoftenreferredto,aredevicesthatareusedforairconditioningor cooling in drier climates (southwest, desert areas, etc.)…where dry-bulb temperatures of 90°F or more occursimultaneouslywith wet-bulb temperatures of 75°F and below. Thewider this gap, the greater the opportunity forefficientevaporativecoolerapplications.Theyaccomplishcoolingbyaddingmoistureorhumiditytotheambientair.

Inmostequipmentdesigns,waterisallowedtoflowoveramediaorevaporativepadwhilewarm,dryambientairisforcedorblownacrossthewetmedia.Evaporationisinduced,andthedryambientairiscooled.Evaporativecoolerscanbeusedtodirectlycoolambientairforcomfortairconditioning,orusedas“precoolers”onmechanicalairconditioning(aircooled)condensers.

Nearlyallwatersupplies,particularlythoseinthedryaridregions,arescale-formingduetothepresenceofhardness,alkalinityandsilicaminerals.Asthiswaterisbroughtintoanevaporativecoolerandevaporated,thesescale-formingmineralsremainbehindintherecirculatingwater.Eventually,thedissolvedmineralsbecomesoconcentratedinthewaterthattheybeginto“fallout”orprecipitateasscale.ThemosteffectivewaytocontrolthisproblemistouseaninorganicpolyphosphatelikeMicromet,andtherecommendedproductisaspecialpolyphosphatecalled6RMicromet.

Today,6RMicrometcanbeeasilyappliedtoevaporativecoolersthroughtheuseoftheNPSeries.TheNPSeriesconsistsoftwohousingsthatwilleachholdtheirowncartridgeof6RMicromet.TheNP24DDwillholdtheNP246Rcartridgeandcantreatasystemupto5500cfmwhiletheNP48DDwillholdtheNP486Rcartridgeandcantreatasystemupto10,000cfm.Multiplesofthesehousings,usedinconjunctionwithoneormoreofthecustombrackets,canprovidetreatmentonunitsupto20,000cfm.Inallcases,treatmentwilllastforsixmonths.

Capacity NP NP Bleed of Cooler Housing(s) Bracket Rate 5500cfm NP24DD ––––– 9.0fl.oz. permin.

10,000cfm NP48DD ––––– 16.0fl.oz. permin.

15,000cfm NP24DD(x3) NP3BR 24.0fl.oz. permin.

20,000cfm NP48DD(x2) NP2BR 32.0fl.oz. permin.

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SAMPLE FIELD REPORT

Name:__________________________________________________________________________________________

Address:________________________________________________________________________________________

PhoneNumber:_____________________City:_____________________State:__________ZipCode:___________

Date: Make-upWater RecirculatingWater

alkalinity __________ppm __________ppmhardness __________ppm __________ppmsilica __________ppm __________ppmpH __________ __________chlorides __________ppm __________ppmconductivity __________µmhos __________µmhos

Date: Make-upWater RecirculatingWater

alkalinity __________ppm __________ppmhardness __________ppm __________ppmsilica __________ppm __________ppmpH __________ __________chlorides __________ppm __________ppmconductivity __________µmhos __________µmhos

Date: Make-upWater RecirculatingWater

alkalinity __________ppm __________ppmhardness __________ppm __________ppmsilica __________ppm __________ppmpH __________ __________chlorides __________ppm __________ppmconductivity __________µmhos __________µmhos

Bgpm=––––(tonnage) COC=C=–––––––(forC70)

Ty-IonC70/month=2xBgpm COC=C=–––––––(for340)

No.340L.S.I/Month=Bgpmx.05 COC=C=–––––––(for233)

Comments:_____________________________________________________________________________________

_____________________________________________________________________________________________

_____________________________________________________________________________________________

.03C-1

600mu/alk

480mu/alk

500mu/alk

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Nu-CalgonWholesaler, Inc. is committed tohelpprovideyouwitha successfulandefficientwater treatmentprogram.Ifwecanbeofanyassistancetoyouinanyway,pleasedonothesitatetocontactus.Arepresentativecanbecontactedbycalling1-800-554-5499andaskingtobeputintouchwithyourlocalrepresentative.Wecanalsobecontactedthroughanyofthemajorair-conditioningrefrigerationwholesalersinyourarea.

PRODUCT LISTING

CHEMICALS

No.340LiquidScaleInhibiter,1-gallon...........................................................................................................4340-08No.340LiquidScaleInhibiter,5-gallon...........................................................................................................4340-05No.340LiquidScaleInhibiter,55-gallon.........................................................................................................4340-01Ty-Ion®C70,5-gallon.........................................................................................................................................7597-05Ty-IonC70,15-gallon.........................................................................................................................................7597-P3Ty-Ion®B20,5-gallon.........................................................................................................................................7537-05Cal-Treat®233,5-gallon.....................................................................................................................................4149-05Micromet®Crystals,4lb.....................................................................................................................................4243-97MicrometCrystals,50lb......................................................................................................................................4243-84SeasonTreat®,5lbcanister.................................................................................................................................4364-88Micromet®Plates,50lb.......................................................................................................................................4275-84No.85Algaecide,1-gallon...................................................................................................................................4108-08No.85Algaecide,15-gallon.................................................................................................................................4108-P3No.90Algaecide,4lb..........................................................................................................................................4109-M5No.90Algaecide,50lb........................................................................................................................................4109-M9

EQUIPMENT

No.215DripFeeder............................................................................................................................................4669-W3No.1075DripFeeder...........................................................................................................................................4670-W31-GallonBracket...................................................................................................................................................4606-05-GallonBracket...................................................................................................................................................4607-0CMSFeedPump...................................................................................................................................................4609-1CMS-IVMonitorSystem......................................................................................................................................4608-4No.90AlgaecideFloater.....................................................................................................................................4695-0Micromet®PlateFeedingBags..........................................................................................................................4673-W3No.89ATestKit...................................................................................................................................................4798-2OrganicPhosphorusTestKit................................................................................................................................4804-0Nitrite TestKit.....................................................................................................................................................4797-0

(1007) 3-302Calgon is a licensed trade name.

2008 Altom Ct. • St. Louis, MO 63146 • 800-554-5499 • www.nucalgon.com