refrigerating effect. Furthermore, the gas discharge pressure will exceed its normal value when the
compressor has run for a period not too long, thus making the protective relay actuate and bring to a
stoppage.
REMEDY
Check up how the air has been lef t in the refrigerat ing system. Generally, there are two possibilities:
one is that the air has b een sucked into the system when r epairing due to carelessness, or it has not
been purged out totally when evacuating the system; the other is that there are leak points at the low
pressure end of the refrigerating system. Leak points appear mostly in those low temperature parts or
assemblies, because the evapor ation tempera ture is lower for such low tempera
ture devices ,
especially at the low pressure end, it is easier
for the air goes into the system. Once it has been
ascertained that air does exist in the system, you have to o pen the tubing, re-evacuate it and the n
charge it with refrigerant.
2) Stoppage due to electric troubles
a) Thermostat is out of control
ANALYSIS OF TROUBLE
In case the thermostat does not work in its good order or its temperature sensor has not been installed
properly, frequent stoppage is also likely to occur.
REMEDY
Try to adjust the temperature sensor’s position u ntil the co mpressor can be st arted and stopped
normally. If this cannot be achieved, and the stoppage still occurs repeatedly, it is most likely that the
mechanical parts or contacts are out of order, disassemble the thermostat, make a thorough checkup
and repair it.
b) Overload of electric motor
ANALYSIS OF TROUBLE
Probably, too many things have been put into the refrigerator, and hence the thermal load exceeds its
refrigerating capacity ; or in ca se the power s upply voltage dr ops considerably, the current flowing
through the motor will increase drastically making t he thermal protector actuate and the fuse blown ,
and hence the motor stop s running. If the motor is still running continuously in such a case , it s
windings will be burned out .
REMEDY
Reduce the thermal load, pay attention to the variation in voltage of the power supply.
c) Abnormal thermal protection
ANALYSIS OF TROUBLE
The compressor current is within its normal range, but the thermal protector actuates repeatedly.
REMEDY
Replace the thermal protector with a new one.
3) Sudden stoppage due to other causes
NORMAL STOPPAGE
Start and stop of the compressor is generally controlled by a thermostat . When the temperature in the
refrigerator reaches it s d esired value, the thermost at will shut down the compressor automatically .
Never take this normal operation as a trouble, care s hould be taken to differentiate it from other rea l
troubles in servicing.
D. Compressor won 't start
In case the compressor cannot be started, you must find out the origins of this trouble through checkup
