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Section E - R-134a Service Information
CAUTION
If you use a vacuum pump with mineral oil to
evacuate an R-134a system, it is ABSOLUTELY
ESSENTIAL to have a shut-off valve between
pump and your manifold gauge set as shown
in Figure E2. The hand valve must be closed
during all times when vacuum pump is
not operating. This will prevent migration
of mineral oil vapor into R134a/Ester oil
system. If vacuum pump should stop during
evacuation for any reason, the hand pump
shut-off valve must be closed immediately.
Refrigerant Leaks
AsystemwithR-134aandEsteroilwillbecome
saturatedwithmoisturemuchfasterthanasystem
withR-12andmineraloil.Ifyourleakwasinthe
lowsideoftherefrigerationsystemwhenthe
compressorisrunningthepressureinthelowside
willgointoavacuum.Asadditionalrefrigerant
leaksoutthesystemwillgodeeperintoavacuum.
Thesystemrunninginthisvacuumwillallowair
andmoisturetobepulledintothesealedsystem.
Themoisturepulledincanthenbemixedintothe
Esteroilinthecompressor.
Iftheproducthashadalowsideleakyouwillneed
toinstallthetwostageservicedryerlterpart
number5303918288.Youmustheatthecrankcase
areaofthecompressorusingaheatgunonthe
highheatsettingthoughoutthe30minutesyouare
runningyourvacuumpumptopullavacuumonthe
system.Every4to5minuteswhileyouarerunning
yourvacuumpumpandheatingthecrankcasearea
shakethecompressor.Byheatingthecrank-case
youareheatingtheoilinthecompressor.Thiswill
drivethemoistureoutoftheoil.Byshakingthe
compressorthiswillallowthemoisturetocometo
thetopoftheoilfastersothevacuumpumpcan
removethemoisturefromthesystem.
Electrolux Home products does not approve
the use of the Sweep Charge for sealed system
repair. Thismethodofservicingsealedsystems
weknowisoftenusedtorepairproductsinthe
eld.TheSweepChargedoesnotadequately
removethemoisturefromtheoilinthecompressor.
InaR-134asystemyouwillneedtoreplacedthe
compressoriftheproducthashadalowsideleak
andyouareservicingwiththeSweepCharge
procedure.
R-134arefrigerantmoleculesaresmallerthanR-12
molecules.ThismeansthatR-134awillpassmore
minorleaksandtherateofowwillbegreater
thanforR-12.Therefore,itisnowmoreimportant
thanevertofollowgoodbrazingpractices.Usea
goodgradeofsilversolder.45%silversolderis
recommended.
Leak Detection
R-134asystemleakscanbepinpointedbymeans
ofanelectronicleakdetectororbybubblesolution.
ElectronicleakdetectorsforR-134aserviceare
currentlyavailablefromseveralmanufacturers.The
leastexpensivemodelsarenon-selectivedetectors
thatwilldetectanytypeofemissionorvapor
present,regardlessofitschemicalcomposition.
Somenon-selectivedetectorsdesignedforuse
withR-12mayhaveamuchlowersensitivity
whenusedwithR-134a.However,newlydesigned
detectorswithgoodR-134asensitivityarenow
available.Besuretoconsultwiththemanufacturer
beforeselectingorusinganon-selectivedetector
withR-134a.
Halogen-specicdetectorsuseaspecialized
sensorthatallowsdetectionofcompounds
containingchlorine,uorine,bromine,andiodine
withoutbeingactiviatedbyotherspecies.The
majoradvantageofthistypeofdetectorisa
reductioninthenumberof“nuisancealarms”.
Halogen-specicdetectorsaregenerallymore
expensivethannon-selectivedetectorsbutfeature
highersensitivity.