SERVICE MANUAL
Model: HRF-663ISB2
31
Issue
2010-01
Rev.
Ref1001S015V0
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 let the air
come in, or use a fan to speed up air flowing so as to shorten the time needed for defrosting .Never
strike the frost layer with any iron tools or wood stick in order to avoid damage to the evaporator
tubing.
6) Refrigerating oil left in evaporator tubing
Analysis of Trouble
During the process of refrigerating cycles, a little refrigerating oil may remain in the evaporator tubing,
and after a longer time of operation, if there is considerable refrigerating oil left in the evaporator, the
heat conduction effect will be severely affected, thus causing a poor refrigerating effect.
Remedy
It is quite difficult to determine whether this trouble is caused by the refrigerating oil left in the
evaporator tubing, because this kind of
Maintenance Service and Trouble Shooting phenomenon and other several trouble are tends to be
confused .Generally speaking, you can make a judgment based on the frost formed on the
evaporator .If the frost does not cover the evaporator, and moreover, it is loosely formed ,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 refrigerating system was originally not purged thoroughly ,some of the filter screen
meshes have been clogged by dirt accumulated in the filter after using it for a certain 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 .
