En-2
2-7.Checkstotherefrigerationequipment
• Whereelectricalcomponentsarebeingchanged,theyshallbetforthepurpose
andtothecorrectspecication.
• Atalltimesthemanufacturer’smaintenanceandserviceguidelinesshallbefollowed.
• Ifindoubtconsultthemanufacturer’stechnicaldepartmentforassistance.
• Thefollowingchecksshallbeappliedtoinstallationsusingammablerefrigerants.
-Thechargesizeisinaccordancewiththeroomsizewithinwhichtherefrigerant
containingpartsareinstalled.
-Theventilationmachineryandoutletsareoperatingadequatelyandarenot
obstructed.
-Ifanindirectrefrigeratingcircuitisbeingused,thesecondarycircuitshallbe
checkedforthepresenceofrefrigerant.
-Markingtotheequipmentcontinuestobevisibleandlegible.Markingsandsigns
thatareillegibleshallbecorrected.
-Refrigerationpipeorcomponentsareinstalledinapositionwheretheyareunlikely
tobeexposedtoanysubstancewhichmaycorroderefrigerantcontainingcompo-
nents,unlessthecomponentsareconstructedofmaterialswhichareinherently
resistanttobeingcorrodedoraresuitablyprotectedagainstbeingsocorroded.
2-8.Checkstoelectricaldevices
• Repairandmaintenancetoelectricalcomponentsshallincludeinitialsafetychecks
andcomponentinspectionprocedures.
• Ifafaultexiststhatcouldcompromisesafety,thennoelectricalsupplyshallbe
connectedtothecircuituntilitissatisfactorilydealtwith.
• Ifthefaultcannotbecorrectedimmediatelybutitisnecessarytocontinueopera-
tion,anadequatetemporarysolutionshallbeused.
• Thisshallbereportedtotheowneroftheequipmentsoallpartiesareadvised.
• Initialsafetychecksshallinclude.
-Thatcapacitorsaredischarged:thisshallbedoneinasafemannertoavoid
possibilityofsparking.
-Thattherenoliveelectricalcomponentsandwiringareexposedwhilecharging,
recoveringorpurgingthesystem.
-Thatthereiscontinuityofearthbonding.
3.Repairstosealedcomponents
• Duringrepairstosealedcomponents,allelectricalsuppliesshallbedisconnected
fromtheequipmentbeingworkeduponpriortoanyremovalofsealedcovers,etc.
• Ifitisabsolutelynecessarytohaveanelectricalsupplytoequipmentduringservic-
ing,thenapermanentlyoperatingformofleakdetectionshallbelocatedatthe
mostcriticalpointtowarnofapotentiallyhazardoussituation.
• Particularattentionshallbepaidtothefollowingtoensurethatbyworkingon
electricalcomponents,thecasingisnotalteredinsuchawaythatthelevelof
protectionisaffected.
• Thisshallincludedamagetocables,excessivenumberofconnections,terminals
notmadetooriginalspecication,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.
• Thecheckshallalsotakeintoaccounttheeffectsofagingorcontinualvibration
fromsourcessuchascompressorsorfans.
6.Detectionofammablerefrigerants
• Undernocircumstancesshallpotentialsourcesofignitionbeusedinthesearching
forordetectionofrefrigerantleaks.
• Ahalidetorch(oranyotherdetectorusinganakedame)shallnotbeused.
7.Leakdetectionmethods
• Electronicleakdetectorsshallbeusedtodetectammablerefrigerants,butthe
sensitivitymaynotbeadequate,ormayneedre-calibration.(Detectionequipment
shallbecalibratedinarefrigerant-freearea.)
• Ensurethatthedetectorisnotapotentialsourceofignitionandissuitableforthe
refrigerantused.
• LeakdetectionequipmentshallbesetatapercentageoftheLFLoftherefrigerant
andshallbecalibratedtotherefrigerantemployedandtheappropriatepercentage
ofgas(25%maximum)isconrmed.
• Leakdetectionuidsaresuitableforusewithmostrefrigerantsbuttheuseof
detergentscontainingchlorineshallbeavoidedasthechlorinemayreactwiththe
refrigerantandcorrodethecopperpipe-work.
• Ifaleakissuspected,allnakedamesshallberemoved/extinguished.
• Ifaleakageofrefrigerantisfoundwhichrequiresbrazing,alloftherefrigerantshall
berecoveredfromthesystem,orisolated(bymeansofshutoffvalves)inapartof
thesystemremotefromtheleak.
Oxygenfreenitrogen(OFN)shallthenbepurgedthroughthesystembothbefore
andduringthebrazingprocess.
Precautions for using R32 refrigerant
Thebasicinstallationworkproceduresarethesameasconventionalrefrigerant(R410A,
R22)models.
However,paycarefulattentiontothefollowingpoints:
WARNING
• Sincetheworkingpressureis1.6timeshigherthanthatofrefrigerantR22models,
someofthepipingandinstallationandservicetoolsarespecial.(See“2.1.Installation
tools”
.)
Especially,whenreplacingarefrigerantR22modelwithanewrefrigerantR32model,
alwaysreplacetheconventionalpipingandarenutswiththeR32andR410Apiping
andarenutsontheoutdoorunitside.
ForR32andR410A,thesamearenutontheoutdoorunitsideandpipecanbe
used.
• ModelsthatuserefrigerantR32andR410Ahaveadifferentchargingportthread
diametertopreventerroneouschargingwithrefrigerantR22andforsafety.There-
fore,checkbeforehand.[ThechargingportthreaddiameterforR32andR410Ais1/2
inch.]
• BemorecarefulthanR22sothatforeignmatter(oil,water,etc.)doesnotenterthe
piping.
Also,whenstoringthepiping,securelysealtheopeningbypinching,taping,etc.
(HandlingofR32issimilartoR410A.)
CAUTION
1.Installation(Space)
• Thattheinstallationofpipe-workshallbekepttoaminimum.
• Thatpipe-workshallbeprotectedfromphysicaldamage.
• Thatcompliancewithnationalgasregulationsshallbeobserved.
• Thatmechanicalconnectionsshallbeaccessibleformaintenancepurposes.
• Incasesthatrequiremechanicalventilation,ventilationopeningsshallbekept
clearofobstruction.
• Whendisposingoftheproductisused,bebasedonnationalregulations,properly
processed.
2.Servicing
2-1.Servicepersonnel
• Anypersonwhoisinvolvedwithworkingonorbreakingintoarefrigerantcircuit
shouldholdacurrentvalidcerticatefromanindustry-accreditedassessment
authority,whichauthorizestheircompetencetohandlerefrigerantssafelyinac-
cordancewithanindustryrecognisedassessmentspecication.
• Servicingshallonlybeperformedasrecommendedbytheequipmentmanufac-
turer.Maintenanceandrepairrequiringtheassistanceofotherskilledpersonnel
shallbecarriedoutunderthesupervisionofthepersoncompetentintheuseof
ammablerefrigerants.
• Servicingshallbeperformedonlyasrecommendedbythemanufacturer.
2-2.Work
• Priortobeginningworkonsystemscontainingammablerefrigerants,safety
checksarenecessarytoensurethattheriskofignitionisminimised.Forrepairto
therefrigeratingsystem,theprecautionsin2-2to2-8shallbecompliedwithprior
toconductingworkonthesystem.
• Workshallbeundertakenunderacontrolledproceduresoastominimizetherisk
ofaammablegasorvapourbeingpresentwhiletheworkisbeingperformed.
• Allmaintenancestaffandothersworkinginthelocalareashallbeinstructedonthe
natureofworkbeingcarriedout.
• Workinconnedspacesshallbeavoided.
• Theareaaroundtheworkspaceshallbesectionedoff.
• Ensurethattheconditionswithintheareahavebeenmadesafebycontrolofam-
mablematerial.
2-3.Checkingforpresenceofrefrigerant
• Theareashallbecheckedwithanappropriaterefrigerantdetectorpriortoanddur-
ingwork,toensurethetechnicianisawareofpotentiallyammableatmospheres.
• Ensurethattheleakdetectionequipmentbeingusedissuitableforusewitham-
mablerefrigerants,i.e.nonsparking,adequatelysealedorintrinsicallysafe.
2-4.Presenceofreextinguisher
• Ifanyhotworkistobeconductedontherefrigerationequipmentoranyassociated
parts,appropriatereextinguishingequipmentshallbeavailableathand.
• HaveadrypowderorCO
2
reextinguisheradjacenttothechargingarea.
2-5.Noignitionsources
• Nopersoncarryingoutworkinrelationtoarefrigerationsystemwhichinvolves
exposinganypipeworkthatcontainsorhascontainedammablerefrigerantshall
useanysourcesofignitioninsuchamannerthatitmayleadtotheriskofreor
explosion.
• Allpossibleignitionsources,includingcigarettesmoking,shouldbekeptsufcient-
lyfarawayfromthesiteofinstallation,repairing,removinganddisposal,during
whichammablerefrigerantcanpossiblybereleasedtothesurroundingspace.
• Priortoworktakingplace,theareaaroundtheequipmentistobesurveyedto
makesurethattherearenoammablehazardsorignitionrisks.“NoSmoking”
signsshallbedisplayed.
2-6.Ventilatedarea
• Ensurethattheareaisintheopenorthatitisadequatelyventilatedbeforebreak-
ingintothesystemorconductinganyhotwork.
• Adegreeofventilationshallcontinueduringtheperiodthattheworkiscarriedout.
• Theventilationshouldsafelydisperseanyreleasedrefrigerantandpreferably
expelitexternallyintotheatmosphere.
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