ARIETE 9020 - Page 25

10. Repair to intrinsically safe components
Do not apply any permanent inductive or capacitance loads to the circuit without ensuring
thatthiswillnotexceedthepermissiblevoltageandcurrentpermittedfartheequipment
in use.
lntrinsicallysafecomponentsaretheonlytypesthatcanbeworkedonwhileliveinthe
presenceofaammableatmosphere.Thetestapparatusshallbeatthecorrectrating.
Replacecomponentsonlywithpartsspeciedbythemanufacturer.Otherpartsmayresult
intheignitionofrefrigerantintheatmospherefromaleak.
11.Cabling
Checkthatcablingwillnotbesubjecttowear,corrosion,excessivepressure,vibration,
sharpedgesoranyotheradverseenvironmentale󰀨ects.Thecheckshallalsotakeintoac-
countthee󰀨ectsofagingorcontinualvibrationfromsourcessuchascompressorsorfans
12.Detectionofammablerefrigerants
Undernocircumstancesshallpotentialsourcesofignitionbeusedinthesearchingforor
detectionofrefrigerantleaks.Ahalidetorch(oranyotherdetectorusinganakedame)
shallnotbeused.
13. Leak detection methods
Thefollowingleakdetectionmethodsaredeemedacceptableforsystemscontainingam-
mablerefrigerants.
Electronicleakdetectorsshallbeusedtodetectammablerefrigerants,butthesensitivity
maynotbeadequate,ormayneedre-calibration.(Detectionequipmentshallbecalibrated
in a refrigerant-free area.) Ensure that the detector is not a potential source of ignition and
issuitablefortherefrigerantused.Leakdetectionequipmentshallbesetatapercentage
oftheLFLoftherefrigerantandshallbecalibratedtotherefrigerantemployedandthe
appropriatepercentageofgas(25%maximum)isconrmed.
Leakdetectionuidsaresuitableforusewithmostrefrigerantsbuttheuseofdetergents
containingchlorineshallbeavoidedasthechlorinemayreactwiththerefrigerantandcor-
rodethecopperpipe-work.
lfaleakissuspected,allnakedamesshallberemoved/extinguished.
lfaleakageofrefrigerantisfoundwhichrequiresbrazing,alloftherefrigerantshallbe
recoveredfromthesystem,orisolated(bymeansofshuto󰀨valves)inapartofthesys-
temremotefromtheleak.Oxygenfreenitrogen(OFN)shallthenbepurgedthroughthe
systembothbeforeandduringthebrazingprocess.
14. Removal and evacuation
Whenbreakingintotherefrigerantcircuittomakerepairs-orforanyotherpurpose-con-
ventionalproceduresshallbeused.However,itisimportantthatbestpracticeisfollowed
sinceammabilityisaconsideration.Thefollowingprocedureshallbeadheredto:
- removerefrigerant;
- purgethecircuitwithinertgas;evacuate;
- purgeagainwithinertgas;
- openthecircuitbycuttingorbrazing.
Therefrigerantchargeshallberecoveredintothecorrectrecoverycylinders.Thesystem
shallbe“ushed”withOFNtorendertheunitsafe.Thisprocessmayneedtoberepeated
severaltimes.Compressedairoroxygenshallnotbeusedforthistask.
FlushingshallbeachievedbybreakingthevacuuminthesystemwithOFNandcontinuing
tolluntiltheworkingpressureisachieved,thenventingtoatmosphere,andnallypulling
downtoavacuum.Thisprocessshallberepeateduntilnorefrigerantiswithinthesystem.
WhenthenalOFNchargeisused,thesystemshallbeventeddowntoatmosphericpres-
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