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Maintenance Service and Trouble Shooting
Hums from a fully enclosed aggregate unit is the sound caused by
overload indicating that the motor cannot be started normally ,meanwhile ,a
clattering sound can be heard from inside the start relay ,which is produced
because the start contacts cannot be released normally .A whistling sound
is caused by the high pressure gas flowing out of the crack of the pressure
tube inside the compressor ,and clucks are the sound of striking after the
suspended spring inside the compressor has broken .
During the normal operation of compressor, a slight and uniform hum
sound due to undulation of electric current can be heard generally ,this is a
normal phenomenon .However ,if it sounds like "tong ,tong … ",i.e., an
impact sound inside the compressor ,this means that a large quantity of wet
vapour of refrigerant or refrigerating oil has come into the compressor
cylinder ;if it sounds like "dang ,dang
…
", a striking sound of metal parts
inside the compressor ,this means that some moving parts have loosened
(note to differentiate this sound from those formed during starting or
stopping the compressor).
b) Listen to the sound caused by the flowing of gas in the evaporator
Open the Freezer door while the compressor is in operation, incline
your ear and listen attentively the gas flow sound inside the evaporator .If it
sounds like gentle whistling accompanied by a sound similar to water
flowing ,this is the sound produced by the normal circulation of refrigerant
within the evaporator .In case only the gas flowing sound can be heard and
there is no water flowing sound ,this indicates that the refrigerant has
already percolated .If neither the flowing sound nor the gas sounds from
the evaporator can be heard ,this means that the filter or capillary has been
clogged .
3)Touch and Feel
a) Feel the compressor when running ,its temperature should be
generally less than 90
°
C in the normal state (it may exceed 90
°
C in case
of running for a longer period of time ).
b) After the compressor has operated normally for 5~10 minutes ,
ouch and feel the condenser ,the temperature of its upper part should be
higher than that of its lower part (or its right part is hotter than its left
part ,depending on the type of condenser coil ),this indicates that the
refrigerant is circulating . If the condenser is not hot ,this means the
leakage of refrigerant .In case the condenser radiates heat for only several
minutes and then cools down ,this means that the filter and capillary have
been clogged .As for the forced air cooling condenser ,hot air will be blown
out of it ; this means that the system is out of order .
c) Feel the filter's temperature .During the normal operation of
refrigerating system ,the temperature on the filter's surface should be a
little higher than the ambient temperature ;if you touch it with your
hand ,you will have a sense of slight heat .In case dew condensation
appears due to the fact that its temperature is obviously lower than the
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