Maintenance Service and Trouble Shooting
many joints and sealed surfaces in a
There are so
refrigerator ,accordingly ,quite a lot potential leak points do exist in the
system .In troubleshooting ,pay attention to those parts that are liable to
leak ,check main connection points for oil seepage and tubing for cracks .If
there is no severer leak point ,charge the system with nitrogen and detect
leak points with the commonly adopted method ,repair
them ,evacuate ,charge the system with refrigerant ,and then turn on the
refrigerator to make a test run .
2) Too much refrigerant charged into the system
Analysis of Trouble
a) In case the amount of refrigerant charged into the system exceeds
its nominal capacity ,the superfluous refrigerant will of course take some
space of the evaporator ,thus reducing its heat-dissipation area and hence
the refrigerating efficiency of the system .The abnormal phenomena
caused by this reason are as follows :the gas suction and exhaust
pressures are generally higher than their respective normal values ,the
temperature of its condenser is higher and the electric current of the
compressor rises ,loose frost forms on the evaporator ,the refrigerator
temperature drops slowly ,and frost appears on the gas return tube .
b) In case excessive refrigerant has been charged, the liquid
refrigerant that cannot 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
achine 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
18
