Advertisement
Thermostat generally controls start and stop of the compressor. When the temperature in the
refrigerator reaches its desired value, the thermostat will shut down the compressor automatically.
Never take this normal operation as a problem; care should be taken to differentiate it from other
real problems in servicing.
Compressor won 't start.
In case the compressor cannot be started, you must find out the origins of this trouble through
systematic checkup, because probably there are many causes, including the electrical and
mechanical parts.
a) Inspect the power supply to see whether it is connected to the compressor circuit.
Analysis of Trouble
In case the compressor cannot be started, this will generally exhibit in the power supply circuit,
for instance, power failure, poor contact of switch, and blown fuse. Make a comprehensive
analysis of these phenomena, find out its real cause and take corrective measures to resolve the
problem.
Remedy
i) Check the input power circuit to see whether there is voltage in the power supply, note: the
circuit that is connected to the knife switch. This can be determined with a voltmeter or a test
pencil. If a blown fuse is found, ascertain and remove its cause, then replace it with a new
one of the same specifications.
ii) Check the compressor accessories, including its thermal protector and relay. In case the
thermal protector is damaged, the compressor cannot be powered on. If the relay is out of
order, the motor will not run and hum sound can be heard from it after the compressor is
turned on. In that case, shut it down immediately, otherwise, the motor windings will be
burned out in case this condition lasts longer.
iii) Check the relay contacts and plugs to see if they are perfect and work reliably. Poor contact
may cause the motor not running or humming.
b) Check the circuit voltage to see whether it is normal
Analysis of trouble
If the circuit voltage is obviously lower than its rated value, it will be difficult to start the motor,
and a hum sound can be heard from it.
Remedy
Measure the voltage with a voltmeter; if it is really too low, give directions to the user for buying
a stabilizer to step up the voltage, thus normal operation can be achieved.
26
Advertisement
