ANALYSIS OF SERVICE AND TROUBLE SHOOTING
Part 6 Analysis of Troubles and Troubleshooting
A. Poor Refrigerating Effect
The so-called “poo r refrigerating effect “ refers to the fact that the refr igerator can ope rate and
refrigerator normally ,but the temp erature in t he refrigerato r cannot drop to the prescribed valu e
under the stipulated w orking conditions .In view of there ar e many causes for this phen omenon ,we
are going to discuss and analyze it in the following 7
aspects :
1) Leakage of refrigerant
ANALYSIS OF TROUBLE
The leakage of refrigerant in t he system will result in an insuf
ficient refrigerating capacity ,th e
resulting phenomen a ar e it s lower gas suction pressure an d exhaust pressure as well as highe r
exhaust gas temperature .The exhau st tube feels rather hot ,and a continuous gas flo wing soun d
louder than usual can be heard at the outlet of the capillary ,and no frost or a smaller quantity of loose
frost appears on the evaporator .After shut down ,the balance pressure in the system is usually lower
than the saturation pressure corresponding to the same ambient temperature .
REMEDY
In case there is leaka ge of refrigerant from
the system ,do not h
urry to recharg e it with
refrigerant ,manage to f ind out leak point s immediatel y ,an d make a n ote of from wher e it lea ks
---welding points and parts .After having them repaired ,recharge refrigerant . There are so many joints
and sealed surfaces in a refrigerat or ,accordingly ,quite a lot potent ial le ak point s 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 amou nt of refrigera nt charged in to the syste m exceeds it s nominal cap acity ,the
superfluous refrigerant will of course t
ake so me sp ace of the evaporat or ,thus reducing it s
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 ,lo ose frost fo rms on the evaporator ,the refrigerator temper ature drop s
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 st riking” will o ccur .The
liquid refrige rant evap orates and ef fervesces as soon as it flows into the refrigerati ng oil at th e
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
ccording to the ope rating procedu res ,it is mandator y to turn the machine of f ,and everal minute s
later ,open the refrigera nt charging tube and let t
he refrigerant escape om it ,replace the dry
