Maintenance Service and Trouble Shooting
Analysis of Trouble
Leak points in the refrigerating system have not been found and repaired timely. thus
resulting in the total escape of refrigerant .There are two kinds of leakage :
l)
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 the refrigerator is gradually becoming not so cold and finally no refrigerating cab be
achieved ;
ii)
Fast leakage
In that case .all the refrigerant 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 been found ,repair them or replace them with new parts according to
specific circumstances .then evacuate the system and finally charge refrigerant.
2) Refrigerating system 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
D
C, 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.
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