TM9-4120-400-14
]
REFRIGERATION SYSTEM TROUBLESHOOTING.
Examination
This task covers:
INITIAL SETUP
Equipment Condition
Unit operating in full cool.
EXAMINATION
1. Check sight glass condition.
A bright green color indicates that the refrigerant is dry. As moisture content increases, the color will
a.
gradually change from chartreuse until it reaches pure yellow. A gradual change from green into
chartreuse over an extended period of time is normally an indication that the dehydrator is becoming
saturated with moisture. A sudden change of color is highly unlikely unless a rupture occurs allowing all
refrigerant to escape. Correct as indicated.
NOTE
When the system goes into bypass numerous bubbles will appear. This is normal. Be
sure that the refrigeration system is under full load when observing the sight glass for
refrigerant condition.
b. The appearance of an occasional bubble in the sight glass can be expected, especially when operating in
a high ambient temperature. A gradual increase in the number and frequency of bubbles is usually an
indication that the refrigerant charge is being lost from the system through a small leak. The number and
frequency of bubbles will also increase if the refrigeration system becomes overheated. The sudden
appearance of numerous bubbles is usually an indication of a serious leak. Correct as indicated.
2.
Check for decreased cooling capacity.
A reduction in cooling capacity will occur as a natural result if refrigerant is lost from the system; with a total
loss of cooling if all refrigerant is lost. However, in some conditions a considerable proportion of the
refrigerant may be lost before the reduced cooling capacity is noticeable. Sudden or erratic reduction, or
complete loss of cooling capacity is often caused by the malfunction of one of the valves in the
refrigeration system. Cooling capacity will also be reduced if the refrigeration system becomes
overheated. Correct as indicated.
NOTE
FOLLOW-ON MAINTENANCE:
Turn unit OFF.
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