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CAUTION
2-Servicing
2-1Servicepersonnel
• Anypersonwhoisinvolvedwithworkingonorbreakingintoarefrigerantcircuit
shouldholdacurrentvalidcerticatefromanindustry-accreditedassessment
authority,whichauthorisestheircompetencetohandlerefrigerantssafelyinaccor-
dancewithanindustryrecognisedassessmentspecication.
• Servicingshallonlybeperformedasrecommendedbytheequipmentmanufacturer.
Maintenanceandrepairrequiringtheassistanceofotherskilledpersonnelshallbe
carriedoutunderthesupervisionofthepersoncompetentintheuseofammable
refrigerants.
• Servicingshallbeperformedonlyasrecommendedbythemanufacturer.
2-2Work
• Priortobeginningworkonsystemscontainingammablerefrigerants,safetychecks
arenecessarytoensurethattheriskofignitionisminimized.Forrepairtotherefrig-
eratingsystem,theprecautionsin2-2to2-8shallbecompliedwithpriortoconduct-
ingworkonthesystem.
• Workshallbeundertakenunderacontrolledproceduresoastominimizetheriskof
aammablegasorvapourbeingpresentwhiletheworkisbeingperformed.
• Allmaintenancestaffandothersworkinginthelocalareashallbeinstructedonthe
natureofworkbeingcarriedout.
• Workinconnedspacesshallbeavoided.
• Theareaaroundtheworkspaceshallbesectionedoff.
• Ensurethattheconditionswithintheareahavebeenmadesafebycontrolofam-
mablematerial.
2-3Checkingforpresenceofrefrigerant
• Theareashallbecheckedwithanappropriaterefrigerantdetectorpriortoandduring
work,toensurethetechnicianisawareofpotentiallyammableatmospheres.
• Ensurethattheleakdetectionequipmentbeingusedissuitableforusewitham-
mablerefrigerants,i.e.nonsparking,adequatelysealedorintrinsicallysafe.
2-4Presenceofreextinguisher
• Ifanyhotworkistobeconductedontherefrigerationequipmentoranyassociated
parts,appropriatereextinguishingequipmentshallbeavailableathand.
• HaveadrypowderorCO
2
reextinguisheradjacenttothechargingarea.
2-5Noignitionsources
• Nopersoncarryingoutworkinrelationtoarefrigerationsystemwhichinvolves
exposinganypipeworkthatcontainsorhascontainedammablerefrigerantshall
useanysourcesofignitioninsuchamannerthatitmayleadtotheriskofreor
explosion.
• Allpossibleignitionsources,includingcigarettesmoking,shouldbekeptsufciently
farawayfromthesiteofinstallation,repairing,removinganddisposal,duringwhich
ammablerefrigerantcanpossiblybereleasedtothesurroundingspace.
• Priortoworktakingplace,theareaaroundtheequipmentistobesurveyedtomake
surethattherearenoammablehazardsorignitionrisks.“NoSmoking”signsshall
bedisplayed.
2-6Ventilatedarea
• Ensurethattheareaisintheopenorthatitisadequatelyventilatedbeforebreaking
intothesystemorconductinganyhotwork.
• Adegreeofventilationshallcontinueduringtheperiodthattheworkiscarriedout.
• Theventilationshouldsafelydisperseanyreleasedrefrigerantandpreferablyexpel
itexternallyintotheatmosphere.
2-7Checkstotherefrigerationequipment
• Whereelectricalcomponentsarebeingchanged,theyshallbetforthepurpose
andtothecorrectspecication.
• Atalltimesthemanufacturer’smaintenanceandserviceguidelinesshallbefollowed.
• Ifindoubtconsultthemanufacturer’stechnicaldepartmentforassistance.
• Thefollowingchecksshallbeappliedtoinstallationsusingammablerefrigerants.
-Thechargesizeisinaccordancewiththeroomsizewithinwhichtherefrigerant
containingpartsareinstalled.
-Theventilationmachineryandoutletsareoperatingadequatelyandarenot
obstructed.
-Ifanindirectrefrigeratingcircuitisbeingused,thesecondarycircuitshallbe
checkedforthepresenceofrefrigerant.
-Markingtotheequipmentcontinuestobevisibleandlegible.Markingsandsigns
thatareillegibleshallbecorrected.
-Refrigerationpipeorcomponentsareinstalledinapositionwheretheyareunlikely
tobeexposedtoanysubstancewhichmaycorroderefrigerantcontainingcompo-
nents,unlessthecomponentsareconstructedofmaterialswhichareinherently
resistanttobeingcorrodedoraresuitablyprotectedagainstbeingsocorroded.
2-8Checkstoelectricaldevices
• Repairandmaintenancetoelectricalcomponentsshallincludeinitialsafetychecks
andcomponentinspectionprocedures.
• Ifafaultexiststhatcouldcompromisesafety,thennoelectricalsupplyshallbecon-
nectedtothecircuituntilitissatisfactorilydealtwith.
• Ifthefaultcannotbecorrectedimmediatelybutitisnecessarytocontinueoperation,
anadequatetemporarysolutionshallbeused.
• Thisshallbereportedtotheowneroftheequipmentsoallpartiesareadvised.
• Initialsafetychecksshallinclude.
-Thatcapacitorsaredischarged:thisshallbedoneinasafemannertoavoidpos-
sibilityofsparking.
-Thattherenoliveelectricalcomponentsandwiringareexposedwhilecharging,
recoveringorpurgingthesystem.
-Thatthereiscontinuityofearthbonding.
CAUTION
3-Repairstosealedcomponents
• Duringrepairstosealedcomponents,allelectricalsuppliesshallbedisconnected
fromtheequipmentbeingworkeduponpriortoanyremovalofsealedcovers,etc.
• Ifitisabsolutelynecessarytohaveanelectricalsupplytoequipmentduringservic-
ing,thenapermanentlyoperatingformofleakdetectionshallbelocatedatthemost
criticalpointtowarnofapotentiallyhazardoussituation.
• Particularattentionshallbepaidtothefollowingtoensurethatbyworkingonelectri-
calcomponents,thecasingisnotalteredinsuchawaythatthelevelofprotectionis
affected.
• Thisshallincludedamagetocables,excessivenumberofconnections,terminalsnot
madetooriginalspecication,damagetoseals,incorrectttingofglands,etc.
• Ensurethatapparatusismountedsecurely.
• Ensurethatsealsorsealingmaterialshavenotdegradedsuchthattheynolonger
servethepurposeofpreventingtheingressofammableatmospheres.
• Replacementpartsshallbeinaccordancewiththemanufacturer’sspecications.
NOTE:Theuseofsiliconsealantmayinhibittheeffectivenessofsometypesofleak
detectionequipment.
Intrinsicallysafecomponentsdonothavetobeisolatedpriortoworkingon
them.
4-Repairtointrinsicallysafecomponents
• Donotapplyanypermanentinductiveorcapacitanceloadstothecircuitwithout
ensuringthatthiswillnotexceedthepermissiblevoltageandcurrentpermittedfor
theequipmentinuse.
• Intrinsicallysafecomponentsaretheonlytypesthatcanbeworkedonwhilelivein
thepresenceofaammableatmosphere.
• Thetestapparatusshallbeatthecorrectrating.
• Replacecomponentsonlywithpartsspeciedbythemanufacturer.
• Otherpartsmayresultintheignitionofrefrigerantintheatmospherefromaleak.
5-Cabling
• Checkthatcablingwillnotbesubjecttowear,corrosion,excessivepressure,vibra-
tion,sharpedgesoranyotheradverseenvironmentaleffects.
• Thecheckshallalsotakeintoaccounttheeffectsofagingorcontinualvibrationfrom
sourcessuchascompressorsorfans.
6-Detectionofammablerefrigerants
• Undernocircumstancesshallpotentialsourcesofignitionbeusedinthesearching
forordetectionofrefrigerantleaks.
• Ahalidetorch(oranyotherdetectorusinganakedame)shallnotbeused.
7-Leakdetectionmethods
• Electronicleakdetectorsshallbeusedtodetectammablerefrigerants,butthe
sensitivitymaynotbeadequate,ormayneedre-calibration.(Detectionequipment
shallbecalibratedinarefrigerant-freearea.)
• Ensurethatthedetectorisnotapotentialsourceofignitionandissuitableforthe
refrigerantused.
• LeakdetectionequipmentshallbesetatapercentageoftheLFLoftherefrigerant
andshallbecalibratedtotherefrigerantemployedandtheappropriatepercentageof
gas(25%maximum)isconrmed.
• Leakdetectionuidsaresuitableforusewithmostrefrigerantsbuttheuseof
detergentscontainingchlorineshallbeavoidedasthechlorinemayreactwiththe
refrigerantandcorrodethecopperpipe-work.
• Ifaleakissuspected,allnakedamesshallberemoved/extinguished.
• Ifaleakageofrefrigerantisfoundwhichrequiresbrazing,alloftherefrigerantshall
berecoveredfromthesystem,orisolated(bymeansofshutoffvalves)inapartof
thesystemremotefromtheleak.
Oxygenfreenitrogen(OFN)shallthenbepurgedthroughthesystembothbefore
andduringthebrazingprocess.
8-Removalandevacuation
• Whenbreakingintotherefrigerantcircuittomakerepairs–orforanyother
purpose–conventionalproceduresshallbeused.
However,itisimportantthatbestpracticeisfollowedsinceammabilityisaconsid-
eration.
Thefollowingprocedureshallbeadheredto:
• removerefrigerant
• purgethecircuitwithinertgas
• evacuate
• purgeagainwithinertgas
• openthecircuitbycuttingorbrazing
• Therefrigerantchargeshallberecoveredintothecorrectrecoverycylinders.
• Thesystemshallbe“ushed”withOFNtorendertheunitsafe.
• Thisprocessmayneedtoberepeatedseveraltimes.
• Compressedairoroxygenshallnotbeusedforthistask.
• FlushingshallbeachievedbybreakingthevacuuminthesystemwithOFNand
continuingtolluntiltheworkingpressureisachieved,thenventingtoatmosphere,
andnallypullingdowntoavacuum.
• Thisprocessshallberepeateduntilnorefrigerantiswithinthesystem.
• WhenthenalOFNchargeisused,thesystemshallbeventeddowntoatmospheric
pressuretoenableworktotakeplace.
• Thisoperationisabsolutelyvitalifbrazingoperationsonthepipeworkaretotake
place.
• Ensurethattheoutletforthevacuumpumpisnotclosetoanyignitionsourcesand
thereisventilationavailable.
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