REMEDY
It is quite dif ficult to determine whet her this trouble is cause d by the refrigeratin g oil lef t in the
evaporator tubing ,b ecause this kind of phe nomenon a nd other severa l trouble a re tends to b e
confused .Gener ally spe aking ,you can make a ju dgment based on the frost formed on the
evaporator .If the frost does not cover the evap orator , and moreo ver ,it is loosely for med ,you can
make a judgment that the deterioration of refrigerating effect is due to the accumulation of refrigerating
oil left in the evaporator tubing in case no other troubles have been found . To clear off refrigerating oil
left in the evaporator ,dismantle the evaporator ,purge it thoroughly and then dry it .In case it is difficult
to dismantle it ,charge refrigerant from the evaporator inlet to wash it several times ,then purge and dry
it with nitrogen .
7) Flowing obstructed in refrigerating system
ANALYSIS OF TROUBLE
Because the refriger ating system was originally not purg ed t horoughly ,som e of the filter screen
meshes have been clog ged by di rt accu mulated in the filter af ter using it for a cert ain time of
period ,thus resulting in a decrease in flow rate ,and hence a poorer refrigerating effect .
The abnormal phenomena caused by this kind of slight clogging in the system are as follows: the gas
discharge pressure is lower ,the temperature of discharged gas drops down ,the position clogged has
a temperature lower than that in normal conditions ,and for a severe clogging ,even dew condensation
as frosting may appear .
REMEDY
Purge the tubing ,and after replacing the dry filter with a new one or clearing it thoroughly ,recharge the
system with refrigerant and seal the charging port .
B. No Refrigerating
The phenomenon that the compressor runs normally ,but no frost (or only a little frost ) appears on the
evaporator ,and the refrigerator temperature does not drop down is called “no refrigerating”. There are
many causes for this trouble and it is relatively complicated , too . In servicing ,special attention to
finding direct causes for this phenom enon .Three main potential causes for this trouble are an alyzed
below :
1) All refrigerant in the system has leaked out
ANALYSIS OF TROUBLE
Leak points in the refrigerating system have not been found an d repaired timely ,thus resulting in the
total escape of refrigerant .There are two kinds of leakage :I) slow leakage for instance ,when we want
to use a refrigerator that has been put out of quite a long time ,we find the leakage of refrigerant ,or in
the course of its operation ,we have found that th e refrigerator is gradually becoming no t so cold and
finally no refrigeratin g cab be achieved ; ii) fast leakage in that case ,all the refrigera nt will escape
swiftly due to abrupt rupture of system tubing .
Symptoms of total leakage of refrigerant are mainly as follows : the compressor can be started easily
(if there is no damage to the compressor parts) and its operating current becomes low ,its gas suction
pressure is high and discharge pressure is lower ,the gas discharge tube feels rather cold ,no sound of
gas eruption from the liquid in the evaporator can be heard ,and no will gush out of the process tube if
you cut it open after shutdown .
REMEDY
Check the whole machine , particularly those locations which are liable to leak .After leak points have