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2-7.Checkstotherefrigerationequipment
• Whereelectricalcomponentsarebeingchanged,theyshallbetforthepurpose
andtothecorrectspecication.
• Atalltimesthemanufacturer’smaintenanceandserviceguidelinesshallbefollowed.
• Ifindoubtconsultthemanufacturer’stechnicaldepartmentforassistance.
• Thefollowingchecksshallbeappliedtoinstallationsusingammablerefrigerants.
-Thechargesizeisinaccordancewiththeroomsizewithinwhichtherefrigerant
containingpartsareinstalled.
-Theventilationmachineryandoutletsareoperatingadequatelyandarenot
obstructed.
-Ifanindirectrefrigeratingcircuitisbeingused,thesecondarycircuitshallbe
checkedforthepresenceofrefrigerant.
-Markingtotheequipmentcontinuestobevisibleandlegible.Markingsandsigns
thatareillegibleshallbecorrected.
-Refrigerationpipeorcomponentsareinstalledinapositionwheretheyare
unlikelytobeexposedtoanysubstancewhichmaycorroderefrigerantcontain-
ingcomponents,unlessthecomponentsareconstructedofmaterialswhichare
inherentlyresistanttobeingcorrodedoraresuitablyprotectedagainstbeingso
corroded.
2-8.Checkstoelectricaldevices
• Repairandmaintenancetoelectricalcomponentsshallincludeinitialsafetychecks
andcomponentinspectionprocedures.
• Ifafaultexiststhatcouldcompromisesafety,thennoelectricalsupplyshallbecon-
nectedtothecircuituntilitissatisfactorilydealtwith.
• Ifthefaultcannotbecorrectedimmediatelybutitisnecessarytocontinueopera-
tion,anadequatetemporarysolutionshallbeused.
• Thisshallbereportedtotheowneroftheequipmentsoallpartiesareadvised.
• Initialsafetychecksshallinclude.
-Thatcapacitorsaredischarged:thisshallbedoneinasafemannertoavoidpos-
sibilityofsparking.
-Thattherenoliveelectricalcomponentsandwiringareexposedwhilecharging,
recoveringorpurgingthesystem.
-Thatthereiscontinuityofearthbonding.
3.Repairstosealedcomponents
• Duringrepairstosealedcomponents,allelectricalsuppliesshallbedisconnected
fromtheequipmentbeingworkeduponpriortoanyremovalofsealedcovers,etc.
• Ifitisabsolutelynecessarytohaveanelectricalsupplytoequipmentduringservic-
ing,thenapermanentlyoperatingformofleakdetectionshallbelocatedatthemost
criticalpointtowarnofapotentiallyhazardoussituation.
• Particularattentionshallbepaidtothefollowingtoensurethatbyworkingonelec-
tricalcomponents,thecasingisnotalteredinsuchawaythatthelevelofprotection
isaffected.
• Thisshallincludedamagetocables,excessivenumberofconnections,terminals
notmadetooriginalspecication,damagetoseals,incorrectttingofglands,etc.
• Ensurethatapparatusismountedsecurely.
• Ensurethatsealsorsealingmaterialshavenotdegradedsuchthattheynolonger
servethepurposeofpreventingtheingressofammableatmospheres.
• Replacementpartsshallbeinaccordancewiththemanufacturer’sspecications.
NOTES:Theuseofsiliconsealantmayinhibittheeffectivenessofsometypesof
leakdetectionequipment.
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.
1.1. Precautions for using R32 refrigerant
Thebasicinstallationworkproceduresarethesameasconventionalrefrigerant(R410A,
R22)models.
However,paycarefulattentiontothefollowingpoints:
WARNING
• Sincetheworkingpressureis1.6timeshigherthanthatofrefrigerantR22models,
someofthepipingandinstallationandservicetoolsarespecial.(Referto“2.1.Instal-
lationtools”.)Especially,whenreplacingarefrigerantR22modelwithanewrefriger-
antR32model,alwaysreplacetheconventionalpipingandarenutswiththeR32
andR410Apipingandarenutsontheoutdoorunitside.ForR32andR410A,the
samearenutontheoutdoorunitsideandpipecanbeused.
• ModelsthatuserefrigerantR32andR410Ahaveadifferentchargingportthread
diametertopreventerroneouschargingwithrefrigerantR22andforsafety.Therefore,
checkbeforehand.[ThechargingportthreaddiameterforR32andR410Ais1/2-20
UNF.]
• BemorecarefulthanR22sothatforeignmatter(oil,water,etc.)doesnotenterthe
piping.Also,whenstoringthepiping,securelysealtheopeningbypinching,taping,
etc.(HandlingofR32issimilartoR410A.)
CAUTION
1.Installation(Space)
• Thattheinstallationofpipe-workshallbekepttoaminimum.
• Thatpipe-workshallbeprotectedfromphysicaldamage.
• Thatcompliancewithnationalgasregulationsshallbeobserved.
• Thatmechanicalconnectionsshallbeaccessibleformaintenancepurposes.
• Incasesthatrequiremechanicalventilation,ventilationopeningsshallbekeptclear
ofobstruction.
• Whendisposingoftheproductisused,bebasedonnationalregulations,properly
processed.
2.Servicing
2-1.Servicepersonnel
• Anypersonwhoisinvolvedwithworkingonorbreakingintoarefrigerantcircuit
shouldholdacurrentvalidcerticatefromanindustry-accreditedassessment
authority,whichauthorizestheircompetencetohandlerefrigerantssafelyinaccor-
dancewithanindustryrecognisedassessmentspecication.
• Servicingshallonlybeperformedasrecommendedbytheequipmentmanufacturer.
Maintenanceandrepairrequiringtheassistanceofotherskilledpersonnelshallbe
carriedoutunderthesupervisionofthepersoncompetentintheuseofammable
refrigerants.
• Servicingshallbeperformedonlyasrecommendedbythemanufacturer.
2-2.Work
• Priortobeginningworkonsystemscontainingammablerefrigerants,safety
checksarenecessarytoensurethattheriskofignitionisminimised.Forrepairto
therefrigeratingsystem,theprecautionsin2-2to2-8shallbecompliedwithpriorto
conductingworkonthesystem.
• Workshallbeundertakenunderacontrolledproceduresoastominimizetheriskof
aammablegasorvapourbeingpresentwhiletheworkisbeingperformed.
• 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,shouldbekeptsufciently
farawayfromthesiteofinstallation,repairing,removinganddisposal,duringwhich
ammablerefrigerantcanpossiblybereleasedtothesurroundingspace.
• Priortoworktakingplace,theareaaroundtheequipmentistobesurveyedtomake
surethattherearenoammablehazardsorignitionrisks.“NoSmoking”signsshall
bedisplayed.
2-6.Ventilatedarea
• Ensurethattheareaisintheopenorthatitisadequatelyventilatedbeforebreaking
intothesystemorconductinganyhotwork.
• Adegreeofventilationshallcontinueduringtheperiodthattheworkiscarriedout.
• Theventilationshouldsafelydisperseanyreleasedrefrigerantandpreferablyexpel
itexternallyintotheatmosphere.
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