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v. The temperature of the gas discharge tube drops
vi. There is no sound of gas eruption from the liquid in the evaporator, and
vii. No gas gushes out of the process tube when cut 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 is clogged with ice
Analysis of Trouble
This is typically a result of a poor dryness treatment, improper air purging, or substandard
water content. The symptoms of this condition are:
- Irregular refrigeration, extreme frosting at the clogged area,
- Evaporation temperature drops below 0°C or 32°F,
- Water accumulates and gradually clogs the narrow part of the capillary,
- Frost to melt at the evaporator, there is no sound of gas flowing,
- The gas suction pressure becomes a vacuum.
Note that these phenomena will appear intermittently. In order to know whether the
system is clogged with ice, heat the parts that are suspected with hot water. If the sound
of gas flowing is heard and the gas suction pressure rises, the trouble is that the system
is clogged by ice.
Remedy
If there is too much moisture in the refrigerating system, release the refrigerant, purge the
tubing with nitrogen, and then refill the system with the filtered refrigerant. Another
method is to connect a filter with moisture absorbers, such as silica gel or anhydrous
calcium chloride, to the refrigerating system. Next, replace the filter, evacuate it again,
and fill the system with refrigerant.
3) Refrigerating system is clogged with dirt
Analysis of Trouble
Coarse-grained dirt and refrigerant oil in the system tend to settle and clog the capillary
inlet. Flow of refrigerant stops when the filter screen is completely clogged by dirt. This
condition has the same symptoms as when the refrigerating system is clogged by ice.
However, when you heat the clogged area with a hot towel, there is no reaction. After
rejecting the possibility of ice clogging, it can be concluded that the clogging is due to dirt.
