b. Air left in the system
Analysis
The residual air in the system will circulate with the refrigerant in the system. The major
symptoms are higher gas discharge pressure, higher discharged gas temperature, and poor
refrigerating effect. The gas discharge pressure will exceed its maximum value when the
compressor has run for an extended period of time as a result, making the protective relay
actuate to a stop
Remedy
Check for the process of the presence of air in refrigerating system. Normally, this occur
by three ways:
i.
Air gets into system during repairs for lack of attention or carelessness or refrigerator is
not properly cleaned when evacuating system
ii.
Leaking points at the low-pressure end of the refrigerating system. Leak points appear
in low temperature parts or assemblies. This is because the evaporation temperature is
lower for such low temperature devices, especially at the low-pressure end; it is easier for
the air to go into the system. Once it is clear that air does exist in the system, open the
tubing, re-evacuate it and then charge it with refrigerant.
2. Stoppage due to electric failures
a. Thermostat is out of control
Analysis
When the thermostat does not work or it’s temperature sensor is not properly installed,
frequent stoppage is likely to occur.
Remedy
Adjust the temperature sensor to position until the compressor can be start and stop
normally. The in ability to work normally will continue to the stop repeatedly. It is most
likely that the mechanical parts or contacts are out of order, disassemble the thermostat
and make a thorough checkup and repair it.
b. Overload of electric motor
Analysis
Possibly too many items are in refrigerator resulting in the thermal load exceeding its
refrigerating capacity; or in the case of the power supply voltage decreasing considerably,
the current flowing through the motor increases drastically making the thermal protector
actuate and blow fuse resulting in motor seizure. If motor continues to run in this
situation, its windings will burn out.
Summary of Contents for RF-8888-174
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