Magic Chef MCSR-6085W, Инструкция по эксплуатации

Страница: 20 / 32

20
1) All refrigerant in the system has leaked out Analysis of Trouble Leak points in the
refrigerating system have not been found and repaired timely ,thus resulting in the
total escape of refrigerant .There are two kinds of leakage :I) slow leakage for instance
,when we want to use a refrigerator that has been put out of quite a long time ,we
find the leakage of refrigerant ,or in the course of its operation ,we have found that
the refrigerator is gradually becoming not so cold and finally no refrigerating cab be
achieved ; ii) fast leakage in that case ,all the refrigerant will escape swiftly due to abrupt
rupture of system tubing . Symptoms of total leakage of refrigerant are mainly asfollows
: the compressor can be started easily (if there is no damage to the compressor parts)
and its operating current becomes low ,its gas suction pressure is high and discharge
pressure is lower ,the gas discharge tube feels rather cold ,no sound of gas eruption
from the liquid in the evaporator can be heard ,and no will gush out of the process
tube if you cut it open after shutdown . Remedy Check the whole machine , particularly
those locations which are liable to leak .After leak points have been found ,repair them
or replace them with new parts according to specific circumstances ,then evacuate the
system and finally charge refrigerant.
2) Refrigerating system has been clogged
a) Clogged with Ice
Analysis of Trouble The dryness treatment for the major parts in the refrigerating system
has been performed improperly, the effect of air purging for the whole system is not
good ,or the water content in the refrigerant is out of standard ,all these will cause the
expansion valve to be clogged with ice .The symptom for this trouble are as follows
:the refrigerator sometimes can refrigerate and sometimes cannot :the refrigerator
compartment works normally at the beginning ,but after working for a certain period of
time ,frosting begins at the clogged position ,evaporation temperature reaches below
0°C , water will accumulate at the narrow part of the capillary and clog it gradually ,then
frost begins to melt at the evaporator ,no gas flowing sound can be heard ,and the gas
suction pressure assumes a state of vacuum .Note that these phenomena will appear
intermittently ; sometimes ,the refrigerator works well ,and sometimes not well .In order
to determine whether it is clogged with ice ,heat the suspicious points with hot water to
make ice melt ,and after a while if a gas flowing sound resulting from an abrupt gush is
heard and the gas suction pressure rises as well ,itcan be confirmed that the trouble is
severely affected ,thus causing a poor refrigerating effect . Remedy It is quite difficult to
determine whether this trouble is caused by the refrigerating oil left in the evaporator
tubing ,because this kind of phenomenon and other several trouble are tends to be
confused .Generally speaking ,you can make a judgment based on the frost formed on
the evaporator .If the frost does not cover the evaporator , and moreover ,it is loosely
formed ,you can make a judgment that the deterioration of refrigerating effect isdue
to the accumulation of refrigerating oil left in the evaporator tubing in case no other
troubles have been found . To clear off refrigerating oil left in the evaporator ,dismantle
the evaporator ,purge it thoroughly and then dry it .In case it is difficult to dismantle it
,charge refrigerant from the evaporator inlet to wash it several times ,then purge and
dry it with nitrogen .
7) Flowing obstructed in refrigerating system
Analysis of Trouble Because the refrigerating system was originally not purged
thoroughly ,some of the filter screen meshes have been clogged by dirt accumulated
in the filter after using it for a certain time of period ,thus resulting in a decrease in flow
rate ,and hence a poorer refrigerating effect . The abnormal phenomena caused by this
kind of slight clogging in the system are as follows: the gas discharge pressure is lower
,the temperature of discharged gas drops down ,the position clogged has a temperature
lower than that in normal conditions ,and for a severe clogging ,even dew condensation
as frosting may appear . Remedy Purge the tubing ,and after replacing the dry filter with
a new one or clearing it thoroughly ,recharge the system with refrigerant and seal the
charging port .
B. No Refrigerating
The phenomenon that the compressor runs normally ,but no frost (or only a little frost
) appears on the evaporator ,and the refrigerator temperature does not drop down
is called «no refrigerating». There are many causes for this trouble and it is relatively
complicated , too . In servicing ,special attention to finding direct causes for this
phenomenon .Three main potential causes for this trouble are analyzed
below :