Remedy
Measure the voltage with a voltmeter. If it is really too low, advice user to acquire a
stabilizer to step up the voltage for efficient work
3. Check the thermal relay for proper contacts
Analysis
The contacts of thermal relay sometimes may be open due to the leakage of temperature
sensing agent from the temperature sensor.
Remedy
Remove the relay cover to check up its contact if it is opened it means that the original
setting is not properly set or temperature-sensing agent has leaked out of the temperature
sensor. Turn the adjusting stem of this value in the direction of the lower temperature
graduation and check the contacts to see whether they are closed. If they are still not
closed, dismantle the temperature-sensing disc and immerse it into warm water to see
whether the contacts actuate. If not, it can be preliminarily determined that temperature-
sensing agent has leaked out. It should be replaced with a new thermostat.
4. Problems of motor and other electrical faults
a. Motor windings are damaged or there is a short circuit between turns
Analysis
When motor windings are damaged or short-circuited between turns, the fuse will blow
continuously and the blow out particularly occurs at that instance where you close the
knife switch.
Remedy
Check the terminals and the outer casing for short-circuits and measure the resistance of
each phase with a voltmeter. If short circuit occurs or the resistance of a particular phase
is low, this means that there is no short circuit in the windings and/or between turns, and
that insulation layers are damaged or deteriorated. Another instrument that can also be
used in this inspection is a mega meter. If the insulation resistance is lower than 2 M
Ω
, it
means that the insulation layer has breakdown already. If the motor is damaged, repair or
replaced it with a new one.
b. Control relay faulty
Analysis
Overheating, burns or wearing of control relay contacts will normally show as symptoms,
these will cause poor contact in electricity.
Remedy
Dismantle it for repairs, or replace it with a new one.
a. Poor electric contractor in thermostat
Analysis
Summary of Contents for RF-8888-174
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