泄漏检测

FunctionalTestingGuidanceValveLeak-ByTest

Valve_Leak_By_Test_(lastupdated:8/06)Page1of16

Thisfunctionaltestingguidanceisdesignedtoaidindevelopingtestproceduresforaspecificprojectby

danceshouldbeadaptedasnecessarytoaddressthecontrol

quences,configuration,onally,

codesmayrequtsbadon

thisguidanceshouldbereviewedcarefullytoensurethattheyarecompleteandappropriate.

TestProcedure:ValveLeak-ByTest

Overview

Valvesaretestedforleak-bytodetermineiftheyareleakingwaterwhentheyhavebeencommanded

reveralpossibletestmethods,andthemostappropriateonedependsonwhetherthe

purpoofthetestistodetectsmallleaks(15%ofdesignfloworless)orlargeleaksafterthesystemand

stproceduresaremoretimeconsumingandotherscanbe

cumentcoversthemostcommonvalveconfigurationsforairhandlers,airandwater

terminalandfancoilunits,sthataretime-efficientand

1

providesasummaryguideonthefeaturesandapplicationsofthevariousmethods.

Thisdocumentdescribesthefollowingtestmethods:

g/coolingCoilValves

BalancingValve

WaterTemperatureAcrossCoil

InfraredThermometer

AirTemperatureAcrossCoil—SpotTest

OtherCoilControlValveMethods

AirTemperatureAcrossCoil—2HourTest

DifferentialPressureAcrossCoil

CoilDrainDown

ticIsolationValves

VisualInspection

BalancingValve

InstalledFlowMeter

OtherIsolationValveMethods

UltrasonicFlowMeter

DifferentialPressureAcrossBoilerorChiller

MixedTemperature

PumpDifferentialPressure

FunctionalTestingGuidanceValveLeak-ByTest

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eak-byTestMethodApplicationGuide

TestMethod

CanDetect

SmallLeaks

(<15%)

QuickTo

Perform

MostCommon

Application

CoilControlValves

ingValveYesYesLargeandsmallleaksofairhandlercooling

andheatingwatercoilsandchiller

evaporatorisolationvalves.

emperatureAcross

Coil

YesNoLargeandsmallleaksofairhandlercoils.

edThermometerNoYesLargeleaksorimproperfunctionofsmall

heatingandcoolingcoilsofterminalandfan

coilunitsandradiators.

peratureAcross

Coil-SpotTest

NoYesLargeleaksofairhandlercoils,terminaland

fancoilunits.

oilControlValveMethods

5.1AirTemperatureAcross

Coil-30MinuteTest

PossiblyNoLargeandsmallleaksofairhandlercoils

andairterminalswhendischargeis

monitored.

5.2DifferentialPressure

AcrossCoil

NotusuallyYesLargeleaksofairhandlercoilsandchiller

isolationvalves.

5.3CoilDrainDownYesNoLargeandsmallleaksofairterminalunits.

AutomaticIsolationValves

InspectionYesYesLargeandsmallleaksofchillercondenr

andcoolingtowerisolationvalvesonly.

ingValveYesYesLargeandsmallleaksofchillerandboiler

isolationvalves.

ledFlowMeterYesYesLargeandsmallleaksofchillerandboiler

isolationvalves.

solationValveMethods

4.1UltrasonicFlowMeterPossiblyNoLargeandsmallleaksofchillerandboiler

isolationvalves.

4.2DifferentialPressure

AcrossBoilerorChiller

NoYesLargeleaksofchillerandboilerisolation

valves.

4.3MixedTemperatureNoNoLargeleaksofchillerandboilerisolation

valves.

4.4PumpDifferentialPressureNoYesLargeleaksofchillerandboilerisolation

valves.

FunctionalTestingGuidanceValveLeak-ByTest

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SystemDescription

Valvesapplicableforthetestproceduresincludealltypesofautomaticallycontrolledhydronicvalves

thatrveheatingandcoolingcoilsonairhandlers,fancoilandterminalunits,andradiators,aswellas

automaticisolationvalvesonchillers,coolingtowersandboilers.

ValveConfigurationsandPreferredTestMethods

handlerswithvalveflowratesof30gpmor

more,atestthatwilldetectsmallleaks(<15%)sapplication,the

lveflowratesarebetween15to30gpm,testingasmaller

sample,like30%,r,theBalancingValveMethodisstillpreferredtodetect

veswithflowrateslessthan15gpm,refertotheAirTerminalandFanCoilction

below.

AirTerminals,llythedeviceshavesmallcopper

pipingwithsmallvalvesandnotestportsorothermeansofmeasuringthetemperatureofthewater

rgypenaltyforanindividual

r,inmostprojects

thereisalargenumberofterminaldevices,whichtypicallyjustifiestestingforleak-byusingasampling

eairterminalunitdischargeairtemperatureisnotmonitored,thepreferenceistolook

onlyforlargerleaksu

alternativeapproachforairterminalunitsistorigorouslycheckasampleof10%to15%ofunitsusing

schargeairtemperatureforthe

airterminalunitisavailable,usingtheAirTemperatureAcrossCoil-30minuteTestmethodorthe

InfraredThermometerMethodispreferred.

ancingValveTest(oftenatriple-dutyvalve)onparallelchillers

andboilersisthepreferredmethod,becauitifficientandprovidesconfidentresults,unlessan

inrtionflowmeterhasbeeninstalled.

Sampling

Itmaynotbenecessary,oreconomical,berof

devicestestedandtheiracceptancecriteriadependsonthehowcriticalvalveleak-byistoeithersystem

operation,energyconsumption,ngisamethodthatekstobalancereliable

tionsforsamplingratesaregivenintheprevious

ctions,buttypicallyprojectspecificationswillstipulateeitheragivensamplepercentoraminimum

agivenpercentageofthesamplesfail,allremaining

atinordertomakesamplingeffective,lectionofthedevices

fortestingshouldbedonerandomly.

CorrectionstoLeakingValves

Ifavalveisleakingby,checkthatthevalvestroketimeprogrammedintotheBASis10%or15%longer

umaticactuatorstryincreasingthepressure.

Thevalveclo-offpressureshouldbeatleastequaltothepump’

recommends150%hatthevalveclosundertheforceoftheactuator,not

heclo-offspecificationsforthevalve

andcomparetothewaterpressureinthepipingtomakesurethevalvehasthecapacitytocompletely

ossiblecausforinadequateclosureareincorrectwiring,

stickingcomponentsanddamagedvalvecomponentscaudbycavitationfromoversizedvalves.

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TestEquipment

Eachtestmethodrequiresadifferenttoftools,ral,

typicaltestequipmentcaninclude:

Differentialpressuregage

Digitalthermometer

Infraredthermometer

Ultrasonicflowmeter

Alltestequipthe

methodsdescribedinthisdocumentexcludingtheInfraredThermometerMethod,theabsoluteaccuracy

ofthemeasuringinstrumentisnotcriticaliftheintentofthetestistomeasureadifferentialvalueandthe

sonisthatmeasurementerrorwillbe

mentswithaccuraciesof±1.0Ffor

temperatureand±3%offullscaleforpressuretransducersaresufficientlyaccurateforthispurpo.

However,sincepressuretransduceraccuracyistypicallyratedagainstfullscale,itisrecommendedthat

mple,a0-300psi

transducershouldnotbeudiftheexpectedpressurerangeisbetween30to40psi.

Directflowmeasurementsusingtheinstalledflowmeter(s)oraportableultrasonicflowmeteraremore

ledflowmetersarenormallysufficiently

accurateiftheyhavebeenfactorycalibrated,installedcorrectly,onic

flowmetershavegoodaccuracypotential,butareverynsitivetopipeconditions,urtupandur

application.

hemostdifficultissuewithany

temperature-badleak-bytestmethodisidentifyinganacceptablelocationforthehand-heldtemperature

ojectwillhaveadifferenttofchoicesfortakingtemperature

sadescriptionofthechoiceslistedinorderofthe

mostpreferred(easiestandmostaccurate)ure1foranillustrationofatypical

atthegagesinthisparticular

applicationcan’tbeudfortemperaturemeasurementsbecautheyarenotfittedwithisolation

petcocks.

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lAirHandlingUnitPiping

P/TPorts.P/T(pressure/temperature)portsaredesignedforahand-heldmetaltemperatureprobetobe

cavenathermocouplewireendcanbecarefully

ortsalsoareud

directlyfortakingpressuremeasurements.

thermometerwelltomeasuretemperature,unscrewthethermometerand

inrttheendofthehandheldinstrument’eattransfer

greaaroundthethermocoupleisideal,fftheopeningofthewelltoprevent

heatexchangewiththeambientairwithinsulation(ifinsulationisnotavailable,ucrumpledpaperor

cloth.)Respontimetotemperaturechangesinthewaterareslowerthanwithnsorsdirectlyinthe

waterby1to3minutes.

reandtemperaturegagesinstalledwith

isolationvalvesbetweenthegageandthemainpipecanbeudtomeasurewatertemperaturedirectly.

thehandheldinstrumentthermocoupleintotheopen

pipeendandslowlybleedwateroutpastthethermocouple,ng

tupwithaP/Tportforthethermocoupleandbypassdrainhooffersa―cleaner‖test.

earenoappropriatelylocatedports,wellsorgagestaketemperaturemeasurements

WaterTemperatureAcrossCoilMethodfindalocationatleast

3or4feetawayfromthecoilsothatthepipewalltemperatureatthehand-heldnsorisnotaffected

ipeisinsulated,makeasmallslicethroughthe

insulation,slidethethermocouplewireundertheinsulation,andgetitdirectlyagainstthepipesurface.

Slideitbackandforthafewtimeswhileobrvingthetemperaturereadinguntilgoodcontactismade(i.e.

measuredtemperatureiscloexpectedtemperature).Tapethewiretotheoutsideoftheinsulation,if

necessary,etestiscompleted,make

suretotapeovertheslice

pipe,wipeaitin

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placewithducttapeandcoverwith1/2‖foamor1‖ormoreoffiberglassinsulation,extendingatleast

fourinchesonallsidesofthethermocouple.

TestProcedureOutline

GeneralProcedures

ation

1.1Createatestform

1.2Determineacceptancecriteria

1.3Provideinstructions/precautions

1.4Specifytestparticipantsandroles/responsibilities

allprefunctionalchecklistsforcompleteness

HeatingandCoolingCoilValveTest

ingValveMethod

1.1Testtup

1.2Valveclosureperformance

1.3Returnsystemtonormal

emperatureAcrossCoilMethod

2.1Testtup

2.2Establishbaline

2.3Valveclosureperformance

2.4Returnsystemtonormal

edThermometerMethod

3.1Planning

3.2Testtup

3.3Readings

3.4Interpretation

3.5Returnsystemtonormal

peratureAcrossCoilSpotTestMethod

4.1Testtup

4.2Establishbaline

4.3Valveclosureperformance

4.4Returnsystemtonormal

oilControlValveMethods

5.1AirTemperatureAcrossCoil~30minutetest

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5.2DifferentialPressureAcrossCoil

5.3CoilDrainDown

AutomaticIsolationValveTest

InspectionMethod

1.1CondenrBundleIsolationTest

1.2CoolingTowerIsolationTest

1.3Returnsystemtonormal

ingValveMethod

2.1Testtup

2.2Valveclosureperformance

2.3Returnsystemtonormal

ledFlowMeterMethod

3.1Testtup

3.2Testandevaluation

3.3Returnsystemtonormal

solationValveMethods

4.1UltrasonicFlowMeter

4.2PressureDifferentialAcrossChillerorBoiler

4.3MixedTemperature

4.4PumpDifferentialPressure

GeneralProcedures

ation

gwillbeeasier,moreconclusiveandefficientifthetestprocedure

pingatestformwill

assistindatacollectionandsubquentevaluationandmayallowlesxperiencedstaffto

executethetests.

-bytestsarenormallyasimplepass/failbadon

iningminorleakageoneveryvalvemaynotbepracticalor

,thetestsshouldfocusonthoapplicationsthatcancontributeto

eapplications,anyleak-byresultdesignates

afailedtest.

1.3Provideinstructions/ingthesystemwithno-flowthroughacoilduring

thetestformorethan30minutesmayleadtoindoorcomfortcomplaintsifthespaceis

vebuildingpressuresandpotentialcondensationinhotandhumidclimates

canalsobeaproblem,iftheassociatedexhaustfansarenotshutdownwhensupplyfansare

turnedoff.

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1.4Specifyparticipantsandroles/tingguidanceprovidedinthis

documentcanassistinverifyingpropersystemperformanceinbothnewconstructionand

lowingpeoplemayneedtoparticipateinthetesting

otheFunctionalTestingBasicsctionoftheFunctionalTestGuidefora

dolesand

responsibilitiesshouldbecustomizedbadonactualprojectrequirements.

NewConstructionProjectExistingBuildingProject

CommissioningProviderCommissioningProvider

MechanicalContractorBuildingOperatingStaff

ControlContractorControlsContractor

TABContractor

allprefunctionalchecklistsforcompleteness

Priortoperforminganyfunctionaltests,thecommissioningpre-start,start-up,andverification

checklistsshouldbecompleted,aswellasapplicablemanufacturer'spre-startandstart-up

recommendations.

Prefunctionalchecklistsitemsinclude,butarenotlimitedto,thefollowing:

Technicianavailabletocommandvalvesopenandclodfromthebuildingautomationsystem.

Valvesinnormaloperatingcontrol.

Airhandler,pumpsandwaterheatingandcoolingequipment(boilerandchiller)inrvice.

Sensor(s)isinstalledperthelocationspecifiedontheplans.

Allairhandlingunit(s)beingtestedhavebeenfunctionallytestedandarecapableofrving

normaloperatingloads.

Allterminalunit(s)beingtestedhavebeenfunctionallytestedandcapableofrvingnormal

operatingloads.

Airandwatersystemhavebeenbalancedperdesign.

Centralhotwaterandchilledwaterplantshavebeenfunctionallytestedandarecapableof

rvicenormaloperatingloads.

Allsafetiesandinterlockshavebeentestedandareoperational.

Allquenceofoperationsareprogrammedperdesign.

HeatingandCoolingCoilValveTestProcedures

ingValveMethod

Manyairhandlershavebalancingvalves(circuittters)onthepipestotheirheatingorcooling

coilswhichcanbeudtodetectvalveleakagebymeasuringthepressuredifferenceacrossthe

rtestmethodmustbeudif

testinga3-waycontrolvalve.

ewaterpumpONandensureitisprovidingnormalflowtotheair

llymarkthebalancingvalve’stting,eargage

types,ewtypeadjustments,counttheturnsasyouturnthebalancing

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lbalancingvalvesrvingthecontrolvalvebeingtestedto10%

ancingvalvemustnotbeopenfurtherthanabout10%orasmallcontrolvalve

leakwouldgivetoosmallapressuredropacrossthebalancingvalvetobeconclusive.

ethepressure

resultsareinconclusive,clothemanualisolationvalvesandeifthebalancingvalve

differentialpressurelowers,kingpressure

measurements,besuretokeepthetransduceratthesameelevationduringeachmeasurement

ofagivenportsothatatmosphericpressuredoesn’tskewtheresults.

tethebalancingvalveprecilytothepre-testtting.

emperatureAcrossCoilMethod

Becauoftheeffortrequiredbythismethod,itismostsuitedtolargervalves(>2inches)onair

thodprovidesveryconclusive

resultsandisapplicabletoboth2-wayand3-waycontrolvalves.

ewaterpumpsandtheheatingorcoolingplant(chillerorboiler)ON,so

pflowratemaybefixedorvariable(i.e.,leavein

normalcontrol).Thewatersupplytemperaturetpointtypicallycanbeleftinnormalmode

withanyretquenceinplace,sincetheretisslowinrelationtothetestduration.

inecentralairhandlerorfancoilunitbalinebycommanding

thesupplyandreturnfansOFFandcommandingthecoilvalvebeingtestedto100%open.

Foraterminalbox,balinecanbeestablishedbycommandingairhandlerOFFor

commandingtheprimaryterminalboxairdamper100%clodandthecoilvalvebeing

testedcommanded100%-poweredterminalbox(eitherriesorparallel)is

beingtested,ensuretheterminalboxfaniscommandedOFFinadditiontofollowingthe

damper/dthecentralhot

waterorchilledwaterplants(s,chillers,distributionpumps,etc.)tobeoperating

entofturningofffans,

closingdampers,andopeningthecontrolvalveistoeliminateheattransferfromthewater

hesystemtooperateforapproximatelyfiveminutesto

stabilizethesystem.

Checkthefollowing:

2.2.1Measurethesupplywatertemperaturenearthecoiloruthebuildingautomation

ethereturnwatertemperaturebetween

theo

returnwatermeasurementshouldbemadeatapointonetotwofeet(ormore)away

fromthecoilaswellastwoormorefeetawayfromwherethecoilreturnpipetiesin

entistominimizetheinfluencethatthecoil

gthoftime

thatthemeasurementswillbevalidissignificantlyreduced,theclorthe

measurementsaremadetoeitherthecoilordistributionlines,duetoheattransferin

thepipeandwaterfromthecoil.

2.2.2Thesupplyandreturnwatertemperaturesshouldbewithin1Fofeachotherwhen

thesupplywaterismeasurednearthecoilandwithin3Fwhenthetemperatureis

measuredneartheplant(toaccountforheatlossalongthepipinglength).Recordthis

watertemperaturedifference(supply–return).

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uingfromthelaststepwiththesupplyandreturnwater

temperaturesstabilized,commandthecoilvalveclodandcommandthecorresponding

supplyfanONand/ordamperopen(terminalbox).Theintentistoallowairtoflowacross

thecoilandremoveheator―cool‖hesystemtooperateat

2illustratesthesupplyandreturn

temperatur

3illustrateshowthewatertemperaturewillchangeovertimeatthereturnmeasurement

locationwhenthereisnoleak-by,badonpipediameterandthedifferentialbetweenthe

returnwaterinthepipeandambientairtemperatures.

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

11121314

ElapdTime(minutes)

W

a

t

e

r

T

e

m

p

(

F

)

HWST

HWRT

CHWS

T

CHWR

T

AHUON-

ValveOPEN-

-AHUOFF

-ValveOPEN

-AHUON

-ValveCLOSED

AHUOFF-

ValveOPEN-

-AHUON

-ValveCLOSED

Leak-by

Noleak-by

Leak-by

Noleak-by

HeatingCoilValve

CoolingCoilValve

Figure2CoilValveLeak-byTestIllustration

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0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

2

WatertoAmbientAirTempDifference(F)

W

a

t

e

r

T

e

m

p

C

h

a

n

g

e

1

s

t

H

r

(

F

)1"Pipe

2"Pipe

3"Pipe

Badonstillwaterinmetalpipewith1"areheatloss

aforgeneralreference

only.

Note:the2ndhourwillbejust

slightlylessthanthe1sthour.

Figure3No-Leak-byReturnWaterTemperatureChangeinFirstHour

Checkthefollowing:

2.3.1Measuresupplyandreturnwatertemperatureatthesamelocationudtoestablish

eisleak-byatthecontrolvalve,thereturn

watertemperaturewillchangerapidlyduetotheheattransferoftheairstreamacross

eisnoleak-byatthecontrolvalve,thestagnantreturnwaterwill

3to5minutes,if

thesupply-returnwatertemperaturedifferencehaschangedbymorethan2Fthen

eadingsaretakenlongerthan10minutesafterthevalve

wasclod,theremaybesomedetectablechangeinthereturnwatertemperature

(andthusthesupply–returndifference)evenwhenthereisnoleak-by,asshownin

Figure2andFigure3.

2.3.2Ifthetestdataisinconclusive,tryexecutingtheentiretestagainbutclosingthe

ouldprovidethe

estfails,thetestmustbe

performedagainoncethenecessaryrepairsaremadebytheappropriateparty.

ltestsarecomplete,returnallcontrolparametersbackto

originaltpointsandconditionsperthedesignquenceofoperations.

edThermometerMethod

ThismethodisavariationoftheWaterTemperatureAcrossCoilMethodandmeasuresthe

applicableinidentifyinggross

valvemalfunctionsandisnotgenerallysuitedtodetectingsmallfractionsofleak-by(<10%of

designflow).Itisfastandefficientandisrecommendedforcheckinglargenumbersofreheatcoils

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thodisapplicabletoboth2-

wayand3-waycontrolvalves.

onstruction,informtheconstructionteamthatyouwillneedaccesstoall

minalboxes,thiswillmeankeepingthe

reinfraredthermometerud

ldbeatleastaccurateto±3Fandhavealarge

ariousmodels,thetypicalmeasurementarea-

to-distanceratiosrangefrom8:1to20:1,

example,a20:1ratiomeansthatwhentakingameasurement5feetfromthedevice,the

instrumentwillaveragethetemperaturereadingsovera0.25foot(3inch)diameterspot

[1x5/20].Whereas,an8:1ratioinstrumentwillaveragethesametemperatureovera9inch

rmeasurementarea-to-distanceratio

meansthatamoreaccuratereadingcanbemadeatafurtherdistance.

terminalboxes,commandthecentralairhandlersupplyfansONandthe

respectiveprimaryairvalves100%dalltheheatingcoilvalvesbeingtested

100%least30minutes

morebeforetakinganytemperaturemeasurementssothatanyresidualheatinthecoilhas

fullydissipatedandthecoiltemperatureisnearsupplyairstreamtemperatureforairterminal

boxesandnearroomtemperatureforradiantcoilsorradiators.

dthe

pflowratecanbeleftinnormal

mode,watersupply

temperaturetpointcanbeleftinnormalmodewithanyretquenceinplace.

emperaturereadingusinganinfraredthermometerontheexpodcoil

iantcoilsorfintubestake

kereadingsnearthe

supplyendofthecoil,sincehotwaterfromasmallleakmaybetotallycooledoffbythetime

commendedthatthedistancebetweentheinfrared

thermometerandsurfacebeingmeasuredbe5feetorlesstoensureanaccuratemeasurement.

dcoilendfintubeneartheenteringsupplyshouldreadwithin

10Fto20Fofthesupplyairtemperatureforanairterminalunitorambientairtemperature

foraradiant/fintubedeviceifthereisnoleak-byatthevalveandthesystempass.

Ifhotwaterwasflowingthroughthecoilpriortoclosingthevalveandthetemperature

measurementismadeonthesupplypipingclotothecoilbecauthecoilendisnot

accessible,thentheacceptabletemperaturevariationwillbelargerthantherangeprovided

erthataninsulatedpipewithstagnant170Fsupplywaterina70Froom

willstillbeabout140Fafteronehour(refertoFigure3).Inthiscaifthetemperature

measurementislessthan140F,thereismostlikelynoleak-byatthecoilandthesystem

:Withtheinfraredthermometer,SATatthediffurcouldalsobecheckedand

comparedtoSATattheAirhandler.

ltestsarecomplete,returnallcontrolparametersbackto

originaltpointsandconditionsperthedesignquenceofoperations.

peratureAcrossCoilMethod–SpotTest

Thismethodisfast,ults

mple,a20Fdifferentialcoilwitha

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valveleakageof10%willonlyresultinapproximately2Ftemperaturechangeintheairstream.

Suchasmalldifferentialmaybedifficulttodetectacrosstheentireairstreamviaspot(

point)stisapplicabletocentralairhandlingunitsandterminalunitcoils

witheither2-wayor3-waycontrolvalves.

rehotorchilledwateriscapableofbeingprovidedtoallzonesbeing

dthedistributionwaterpumpsandthecentralheatingandcoolingplants

OFF.

tralairhandlingunits,ing

airterminalboxes,commandthecentralairhandlersupplyfanONandtherespective

primaryairvalves100%dallthecoilvalvesbeingtestedto100%clod.

Thiswilltypicallybebyunitforcentralsystemsandbyfloororgroupoffloorsforterminal

tion,clothemanualisolationvalvesonthesupplyandreturnpipesrving

least30minutesbefore

takinganytemperaturemeasurementssothatanyresidualenergyinthecoilhasfully

dissipated.

Checkthefollowing:

4.2.1Measurethemixedandsupplyairtemperatureupstreamanddownstream,ofthecoil.

Ifpossible,makethemeasurementsusingthesametemperaturensorinveral

locationswithinthemixedairplenumandsupplyairplenumtodetermineanaverage

temperatureforbothparameters.

4.2.2Calculatethedifferentialbetweentheaveragemixedandsupplyairtemperatures.

Theyshouldbewithin2emperaturedifferenceisgreaterthan

2F,thentheremaybensorerror(ifusingmultiplensors)ornotenoughtimehas

additional10minutes

beforetakingthereadingsagain.

uingfromthelaststepwiththecoilvalve100%clod

andthemixed–supplyairtemperaturedifferentialstabilized,openthemanualisolationvalves.

Command

pumpflowratecanbeleftinnormalmode,butshouldbevariable,ifallvalveswillbeshutat

andchilledwatersupplytemperaturetpointcanbeleftinnormalmodewith

least15minutesbeforetakinganymeasurements.

Checkthefollowing:

4.3.1Measurethemixedandsupplyairtemperatureupstreamanddownstream,ofthecoil.

Ifpossible,makethemeasurementsusingthesametemperaturensorinveral

locationswithinthemixedairplenumandsupplyairplenumtodetermineanaverage

temperatureforbothparameters.

4.3.2Calcula

thetemperaturedifferenceisgreaterthan5F,thenthereislikelyleak-byatthevalve.

Withcarefulmeasurements,evena3unately,

thenormalvariationofairtemperatureacrossthecoilandtheinaccuraciesofnsors

don’tallowfirmconclusionswithdifferenceslessthan3esultsare

inconclusive,considerperforminganalternatetest.

nualvalves,releafanandpumpoverrides,etc.

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oilControlValveMethods

Thereareotherviablemethodsfordetectingleak-byoncoilcoolingandheatingvalves,butthey

ebrieflymentionedherefor

reference.

5.1AirTemperatureAcrossCoil~stisviablewhentheBAS

accuratelymonitorsairhandlersupplyandmixedairtemperaturesortheterminalunit

dischargeaironaterminalunitvalvetest(oranarrayofdataloggerscouldbeud).This

methodonlyworksifthensorsonbothsidesofthecoilarecalibratedtobereadingwithin

0.2hodinvolvesmonitoringtheairflowfor30minuteswiththe

controlv

methodismoreconclusivethantheAirTemperatureAcrossCoil—

testandevaluationproceduresarethesameasforthespottest,exceptthatthemixedand

supplyairtemperaturesaretrendedforatleast30minutesat2minuteintervalsoncethe

initial30minutetimedelaytoremoveresidualheatfromthecoilhaxpired.

thodmeasuresthechangeindifferentialpressure

hodisfast,butcanonlydetectlargerleakagerates,sinceasmallleak

ceduresareto

turnONthepumpandcloallmanualcoilisolationvalvesonbothsupplyandreturnto

ferenceshould

,emanualisolation

eadingswiththeautomaticisolation

valvecommandedclodshowaconsistentdifferentialpressureover1psi,thenleak-byis

likely.

thodisabsolutelyconclusive,butissuitedonlytosmallcoilsor

airterminalboxeswith2-waycontrolvalvesinstalledonthesupply-sideofthecoil.

Locationofthecontrolvalveiscriticalsincewaterwillcontinuetoflowtothecoilifthe

tisonlyrecommendedforsmallercoilssince

themethodrequirestheentirecoiltobedraineddown,anditshouldonlybeperformedwhen

utethistest,

commandthecoilvaleto100%lyclotheisolationvalveonsupplysideof

esn’tthereisaleakpastthecontrolvalve.

AutomaticIsolationValves

Themethodsdescribedbelowapplytovalvesdesignedtoisolateequipment,suchaschillers,boilers,and

coolingtowers,lly,testsonisolationvalvesare

performedtofindlargeleaks.

InspectionMethod

dallchillersOFF,allcondenrbundle

isolationvalvesclod,allcoolingtowerisolationvalvesopen,andcondenrwaterpump(s)

lofthecondenrbundleisolationvalvesclodandthecondenrwaterpumps

operating,thisineffectcreatesa―deadhead‖conditiononthepumpandshouldnotbe

lyinspectforanywaterentering

risflowing,rceoftheproblemmustbe

fixedbeforethesystemcanberetested.

FunctionalTestingGuidanceValveLeak-ByTest

Valve_Leak_By_Test_(lastupdated:8/06)Page15of16

uingfromabovewithallchillersOFFandcondenr

waterpump(s)ON,commandallcondenrbundleisolationvalvesopenandallcooling

lofthecoolingtowerisolationvalvesclodandthe

condenrwaterpumpsoperating,thisineffectcreatesa―deadhead‖conditiononthepump

lyinspectfor

risflowing,rceof

theproblemmustbefixedbeforethesystemcanberetested.

ltestsarecomplete,returnallcontrolparametersbackto

originaltpointsandconditionsperthedesignquenceofoperations.

ingValveMethod

Mostchillersandboilersdesignedtooperateinparallelwithotherunitswillhaveautomatic

isolation

distributionpumpsrvingtheunitsmaybeconfiguredasconstantorvariableprimaryflow.

Eachpumpwillbefittedwitheitheratriple-dutyvalveoradedicatedbalancingvalveatthe

dischargeofthepump,lowingprocedures

arequicktoperformandshouldidentifyasmallleakageratethroughthevalve(s)beingtested.

llymarkeachbalancingvalve’sttingbeforemakinganyadjustments.

Forlineargagetypes,ewtypeadjustments,markthestemaswellas

eachbalancingvalvervingthe

isolationvalvebeingtestedto10%opentoensureasmallvalveleakcanbedetected.

CommandallchillersandboilersOFFtoensuretheywillnottrytooperatewithoutanywater

dtheisolationvalveontheunitbeingtestedclod,andclothemanual

donepumpON.

e

arenoleaksinthesystem,thedifferentialpressureacrossthebalancingvalveshouldbezero.

ltsareinconclusive,clothe

manualisolationvalvesonthetestedunitandeifthedifferentialpressureacrossthe

,thenitconfirmsthevalveisleaking.

Whentakingpressuremeasurements,besuretokeepthetransduceratthesameelevation

duringeachmeasurementofagivenportsothatatmosphericpressuredoesn’tskewthe

thisprocedurewithallotherunitstobetested.

tethebalancingvalveprecilytothepre-testttingand

returncontrolledequipmenttoautoorpre-testconditions.

ledFlowMeterMethod

Manylargerboilerandchillersystemscontainpermanentlyinstalledflowmetersontheirprimary

orcondaryloops,cas,

usingtheinstalledflowmeteroffersaneasywaytodetectisolationvalveleakageifthedevicecan

ceduresforusinginstalledflowmetersare

describedbelow.

dallchillersandboilersOFFtoensuretheywillnottrytooperate

dtheisolationvalveontheunitbeingtestedclod,and

lowmeterisinthe

primaryloop,lowmeterisina

condarydecoupledloop,manuallyvalveoffthebypasslegandcommandthecondary

pumpsOFF.

FunctionalTestingGuidanceValveLeak-ByTest

Valve_Leak_By_Test_(lastupdated:8/06)Page16of16

sleak-byiftheflowmeter

thisprocedurewithallotherunitstobetested.

all

automaticdevicestoautoorpre-testconditions.

ethodsforIsolationValves

Thereareotherviablemethodsfordetectingleak-byonchillerandboilerisolationvalves,butthey

ebrieflymentionedherefor

reference.

tproceduresaresimilartotheInstalledFlowMetermethod

stmaybemoretimeconsumingduetothepotentialnecessityto

removean

addition,theaccuracyoftheultrasonicmeteratreducedflowmaymakeitdifficulttoidentify

smallleaks.

thodmeasuresthechangein

differenti

methodisfast,butcanonlydetectlargerleakagerates,sinceasmallleakreprentsavery

ceduresaretoturnthechillerorboilerOFF;turn

ethedifferential

pressureacrossthedevice(whichshouldbezero).Then,commandtheautomaticisolation

valveclod,openthemanualisolationvalves,andmeasurethedifferentialpressureagain.

Ifthereadingswiththeautomaticisolationvalvecommandedclodshowaconsistent

differentialpressureover2psi,thenleak-byislikely.

hodworksforequipmentthatispipedinparallelandthe

entisto

measurethemixedwatertemperaturetodetermineifthereisleakagepastaunitthatisnot

bestillustratedthroughthefollowingexample:Chiller1isONand

producing42

leakagethroughtheChiller2isolationvalve,themixedwatertemperaturewillbe42

thereisleakage,themixedwatertemperaturewouldbehigherduetoblendingofwarm

returnwaterwiththe42tprocedurefollowsthixample–commandone

unitONandtheother(s)ixedtemperatureis

higherthandischargewatertemperaturefromtheunitthatisoperating,

thodmaybe

inconclusiveduetothedifficultyinmeasuringthemixedwatertemperature.

thodissimilartothebalancingvalvemethodexcept

thebalancingvalveis100%clodratherthan10%open,andthedifferentialpressureis

einthedifferentialpressure

acr,many

pumpshaveaveryflatimpellercurve,makingasmallflowrateduetovalveleakagedifficult

todetect.