Haier BC-117A Series Service Manual page 16

a) Listen to the noises produced when the compressor is running
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 refrigerator 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℃ in the normal state (it may exceed 90℃ 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
Maintenance Service and Trouble Shooting
15