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make anoteof fromwhere itleaks---welding points andparts.After having
them repaired ,recharge refrigerant .
There aresomanyjointsandsealedsurfacesina
refrigerator,accordingly,quitealotpotentialleakpointsdo exist in the
system .In troubleshooting ,payattention to those partsthat areliable to
leak ,check mainconnectionpointsforoilseepageand tubing forcracks .If
thereis nosevererleakpoint,chargethesystem with nitrogen anddetect
leak pointswith thecommonlyadoptedmethod,repair
them,evacuate,charge the system withrefrigerant ,andthenturn on the
refrigeratorto make a test run.
2) Too muchrefrigerant charged intothe system
Analysis of Trouble
a) Incasetheamountofrefrigerantcharged intothesystemexceedsits
nominalcapacity,the superfluous refrigerant will of coursetake some space
of the evaporator ,thusreducing itsheat-dissipation area and hencethe
refrigeratingefficiencyof the system .The abnormal phenomena causedby
this reasonare asfollows:thegassuctionandexhaust pressuresare
generallyhigher than their respectivenormalvalues,thetemperature ofits
condenser is higherand the electric current of thecompressor rises,loose
frost forms on the evaporator ,the refrigerator temperaturedropsslowly,and
frost appears on the gas returntube.
b) Incaseexcessiverefrigerant has beencharged,the liquidrefrigerant
that cannotevaporates inthe evaporator will return tothecompressor ,and
thusaphenomenon of “liquid striking”will occur.Theliquid refrigerant
evaporates andeffervesces as soonasit flowsintotherefrigeratingoil at the
bottom ofcompressor .If theconditionissevere,foams will fill alloverinside
the compressor housingand be suckedbythe piston ,causing damageto the
components of compressor.
Remedy
Accordingtothe operatingprocedures ,it ismandatorytoturn themachine
off ,andseveralminuteslater,openthe refrigerantcharging tubeandletthe
refrigerant escape fromit ,replacethe dryfilter ,recharge refrigerantafter
evacuating ,andthen seal thechargingport .
3) Thereis air left in the refrigeratingsystem
Analysis of Trouble
Residual air inthe refrigerating system will reduceits refrigerating
efficiency.The prominentphenomenaaretheincreaseinitsgas suctionand
exhaust pressures(however ,thegasexhaustpressure will not exceed its
ratedvalue ),obvious increaseintemperaturein the segment fromthe
compressoroutletto the condenserinlet.Becausethere isair in the
system ,both thegasexhaustpressureandtemperaturewill rise,and
moreover ,the gas flowing sound is intermittent andobviouslylouder .
Maintenance Service and Trouble Shooting