Haier HRN-186 Service Manual page 11

5.2. Normal Phenomena—Not Troubles for Refrigerators
In a domestic refrigerator, there is not only a complicated electric control system, but also a
refrigerating system that is difficult to discern whether it is in a good working condition. Both the
systems are related and affect each other. If a certain part of a refrigerator works abnormally .Its
refrigerating efficiency will decrease ,operation properties will become unstable ,or even it cannot be
used normally for those serious cases. Refrigerators are generally of larger volume ,once troubles
appear ,to send them to a service department is really a tough thing ,if such is the case ,the user will
always be in suspense ,sometimes ,normal phenomena will be erroneously regarded as
troubles .Therefore ,before we deal with the topics of frequently occurring troubles of refrigerators and
their remedies ,we should firstly give a brief account of some normal phenomena which are not
troubles .In case any one of such phenomena occurs ,there is no need to worry about it ,and the user
can use it at total ease .
1).When the compressor of a refrigerator has just stopped running ,a rumbling sound can be heard
from inside its evaporator .This is a sound caused by the flowing of refrigerant in the evaporator
tubing .Because the pressure difference is still greater after the compressor has just stopped
running ,the refrigerant will flow for a certain time , therefore ,this sound is a normal phenomenon.
2).A click sound can often be heard from the refrigerator .This is a normal sound produced by the
pull-in or release of
compressor .The compressor motor will produce a slight and uniform sound while it is running .This
sound is not easy to be heard in the
daytime ,but of course it can be heard distinctly at night.
3).The compressor consists of an electric motor and a compressing apparatus .During its normal
operation ,the motor's stator core and windings will rise to a temperature in the range of 100℃ ~110
℃ ,and the temperature of the piston and cylinder of the compressing mechanism can also reach as
above 100 ℃ due to the heat produced when compressing refrigerant .Most of the heat radiates to the
air through the compressor casing ,therefore ,its casing is generally at a temperature between 85
℃~90℃ ,it is very hot ,particularly in summer when the ambient temperature is higher .All these are
normal phenomena .
4).For the direct cooling refrigerator ,a kind of irregular crack sound can be often heard when the
compressor is running for a certain period of time or has just stopped its running .This sound is caused
by the stress relief due to expansion and contraction when temperature changes ,and will not affect
the normal application of refrigerator .
5.3. Common Troubles in Refrigerators and Their Remedies
Causes for troubles occurring in refrigerators are closely related to the quality of components and
workmanship in assembling by manufacturers as whether refrigerators are properly used and
maintained .The parameters generally used to express the working conditions of a refrigerator include
the temperature inside the refrigerator ,operation rate ,electric power consumption ,noise level ,and
other functional indexes .If any one of
these parameters is beyond its permissible range ,this indicates that there is a fault or trouble in the
refrigerator . During the whole service life of a refrigerator ,the probability of troubles occurring within a
union time is called its failure rate .Making a comparison between the control circuit system of a
refrigerator and its refrigerating system ,we can find that the failure rate of the former is higher ,and
that of the thermostat is the highest . In
troubleshooting ,the first thing you must do is to determine where the trouble comes from --- the control
the armature of a current deadweight start relay when starting the