Remedy
Check the whole machine, particularly those locations, which are liable to leak. After leak
points have been found, repair them or replace them with new parts according to specific
circumstances, then evacuate the system and finally charge refrigerant.
2) Refrigerating sy stem has been clogged
a) Clogged with Ice
Analysis of Trouble
The dryness treatment for the major parts in the refrigerating system has been performed
improperly, the effect of air purging for the whole system is not good ,or the water content in
the refrigerant is out of standard ,all these will cause the expansion valve to be clogged with
ice .The symptom for this trouble are as follows :the refrigerator sometimes can refrigerate
and sometimes cannot :the refrigerator compartment works normally at the beginning ,but
after working for a certain period of time ,frosting begins at the clogged position ,evaporation
temperature reaches below
0
ć
,
water will accumulate at the narrow part of the capillary and
clog it gradually ,then frost begins to melt at the evaporator ,no gas flowing sound can be
heard ,and the gas suction pressure assumes a state of vacuum .Note that these phenomena
will appear intermittently ; sometimes ,the refrigerator works well ,and sometimes not well .In
order to determine whether it is clogged with ice ,heat the suspicious points with hot water to
make ice melt ,and after a while if a gas flowing sound resulting from an abrupt gush is heard
and the gas suction pressure rises as well ,it can be confirmed that the trouble is caused by
ice clogging .
Remedy
If there is too much moisture in the refrigerating system, it is advisable to release the
refrigerant, purge the tubing with nitrogen, and then charge the system with the filtered
refrigerant. However, the commonly adopted method is to connect a filter with moisture
absorbers (such as silica-gel, anhydrous calcium chloride) to the refrigerating system so as to
filter out the moisture from the system, then replace the filter, evacuate it again and finally
charge the system with refrigerant.
b) Clogged with dirt in capillary
Analy sis of Trouble
The capillary inlet is a place where coarse-grained dirt or refrigerant oil in the system will tend
to settle down and clog it. In case considerable dirt accumulates there, the whole filter screen
may be blocked totally, making the refrigerant unable to go through. Clogging with dirt
exhibits the same symptoms as that with ice, namely, higher gas suction pressure, lower
temperature of discharged gas, and no gas flowing sound from the evaporator. The difference
between the both is as follows: if the clogging is caused by dirt, tapping the suspicious
clogged point (generally in the capillary or the connection joint of the filter) may cause the
refrigerant to flow through partially, resulting in some corresponding change, whereas in that
case if you heat it with a hot towel, no reaction will happen, no flowing sound can be heard,
moreover, there is no periodic change. After rejecting the possibility of ice clogging, it can be
generally considered as the clogging due to dirt.
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Summary of Contents for HB21FNN
Page 23: ...CIRCUIT DIAGRAM 1 Brief principle diagram 23 ...
Page 24: ...2 Connect diagram 24 CIRCUIT DIAGRAM ...
Page 40: ......
