NR-BN30PGW, NR-BN30PGB, NR-BN30PS1, NR-BN30QGW, NR-BN30QGB, NR-BN30QW1, NR-BN30QS1 - Panasonic Other Service Manuals Service Manual (repair manual). Page 14

 

 

14 

7 Analysis of Troubles and Troubleshooting 
 
A. Poor Refrigerating Effect. 
The so-called "poor refrigerating effect " refers to the fact that the refrigerator can operate and 
refrigerator normally ,but the temperature in the refrigerator cannot drop to the prescribed value 
under the stipulated working conditions .In view of there are many causes for this phenomenon ,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 the system will result in an insufficient refrigerating capacity, the 

resulting phenomena are its lower gas suction pressure and exhaust pressure as well as higher 
exhaust gas temperature. The exhaust tube feels rather hot, and a continuous gas flowing sound 
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 leakage of refrigerant from the system, do not hurry to recharge it with refrigerant, 
manage to find out leak points immediately, and make a note of from where it leaks ---welding points 
and parts .After having them repaired, recharge refrigerant . 
There are so many joints and sealed There are so surfaces in a 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 machine off ,and several minutes