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evaporates in the evaporator will return to the compressor ,and thus a phenomenon of
"liquid striking" will occur .The liquid refrigerant evaporates and effervesces as soon as it
flows into the refrigerating oil at the bottom of compressor .If the condition is severe ,foams
will fill all over inside the compressor housing and be sucked by the piston ,causing
damage to the components of compressor .
Remedy
According to the operating procedures ,it is mandatory to turn the machine off ,and several
minutes later ,open the refrigerant charging tube and et the refrigerant escape from
it ,replace the dry filter ,recharge refrigerant after evacuating ,and then seal the charging
port .
3) There is air left in the refrigerating system Analysis of Trouble Residual air in the
refrigerating system will reduce its refrigerating efficiency .The prominent phenomena are
the increase in its gas suction and exhaust pressures (however ,the gas exhaust pressure
will not exceed its rated value ),obvious increase in temperature in the segment from the
compressor outlet to the condenser inlet .Because there is air in the system ,both the gas
exhaust pressure and temperature will rise ,and moreover ,the gas flowing sound is
intermittent and obviously louder .
Remedy
After shut down for several minutes ,open the tubing ,evacuate it and then recharge the
system with refrigerant .
4) Low efficiency of compressor
Analysis of Trouble
Low efficiency of a refrigerating compressor refers to the actual reduction of gas discharge
capacity ,and hence the corresponding reduction of refrigerating capacity ,under the
condition that the refrigerant in the system is unchanged .This phenomenon occurs mostly
when the compressor has been used for quite a long time ,its moving parts have worn to a
considerable degree ,fit clearance between various parts have increased and sealing
property of its gas valve has deteriorated ,resulting in an decrease in its actual gas
discharge capacity .
Methods of Judgment
Measure the high and low pressures with pressure gauges to see whether they are
normal .If an abnormal sound comes from the compressor or the temperature of its causing
is too high ,Cut the discharge port open and operate the compressor ,feel it if there is
pressure at the discharge port with your finger (For a normal compressor ,its discharge port
is difficult to be blocked with your finger if you just apply a little effort).
5) Too thick frost layer formed on evaporator
Analysis of Trouble
If a direct cooling refrigerator is to be used for a prolonged period of time ,be sure to defrost
its evaporator regularly ;if you fail to do so ,the frost layer on the evaporator tubing will
become thicker and thicker .Heat conduction will be severely affected when the whole
tubing is wrapped with a transparent ice layer ,and finally the temperature in the
refrigerator cannot drop down to the prescribed range .
Remedy
Turn the refrigerator off ,and make preparations for defrosting ,open the refrigerator door to
