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6) Refrigerating oil in evaporator tubing
Analysis of Trouble
During the refrigerating cycles, small amounts of refrigerating oil may remain in the
evaporator tubing. However, if there is considerable refrigerating oil left in the evaporator
after an extended period of operation, the heat conduction effect will be severely affected.
The result is poor refrigerating effect.
Remedy
If there is no frost on the evaporator, then there is a high probability that the deterioration
of refrigerating effect is due to the accumulation of refrigerating oil in the evaporator
tubing. Remove accumulated refrigerating oil, dismantle the evaporator, purge it
thoroughly, and then dry it. If it is difficult to dismantle, fill the evaporator tubing with
refrigerant from the evaporator inlet several times to remove the refrigerating oil. Then,
purge and dry it with nitrogen.
7) Flow obstructed in refrigerating system
Analysis of Trouble
If the refrigerating system was not purged thoroughly, the filter screen meshes become
clogged by dirt. This results in a decrease in flow rate and a poor refrigerating effect. The
effects of clogged filters included: decrease of gas discharge pressure, the drop in the
temperature of discharged gas, and, for severe cases, condensation and frosting may
appear.
Remedy
Purge the tubing. After replacing, the dry filter or cleaning it thoroughly, refill the system
with refrigerant and seal the charging port.
•
No Refrigerating
“No refrigerating” refers to a situation where the compressor runs normally, but the
refrigerator’s temperature does not decrease. While servicing, careful attention will be
required to find correct the cause. The most common causes for this malfunction are
analyzed below.
1)
The entire refrigerant has leaked
Analysis of Trouble
Leak points in the refrigerating system have not been found and repaired timely, allowing
refrigerant to leak completely. There are two kinds of leaks: slow leaks
and fast leaks.
Symptoms of total leakage of refrigerant are:
i. The compressor can be started easily (if there is no damage to the compressor parts)
ii. The operating current becomes low
iii. The gas suction pressure increases
iv. The discharge pressure decreases
