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temperature sensor. Try to turn the adjusting stem of this value in the direction of the lower
temperature graduation, and then check the contacts to see whether they are closed. If
they are still not closed, dismantle the temperature-sensing disc and then 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, and it must be replaced with a new
thermostat.
d) Problems of motor and other electrical faults
i) Motor windings are damaged or there is a short circuited between turns
Analysis of Trouble
When motor windings are damaged or there the occurrence of a short circuit between
turns, the fuse will be blown repeatedly, and the blowout particularly occurs at that
instance where you close the knife switch.
Remedy
Check the terminals and the outer casing to see whether they are short-circuited, and
measure the resistance of each phase with an avometer. 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 megameter. If the
insulation resistance is lower than 2 MΩ, this means that the insulation layer has a
breakdown already. If the motor is damaged, repair or replaced it with a new one.
ii) Control relay is faulty
Analysis of Trouble
Overheating, burns or wearing of control relay contacts will generally occur if this is true.
All these will cause poor contact in electricity.
Remedy
Dismantle it for repairs, or replace it with a new one.
iii) Poor electric contractor in thermostat
Analysis of Trouble
Damaged contractor and leakage of temperature sensing agent will generally occur if
this is true.
Remedy
Replace the old one with a new one.
iv) Check the terminals for loose connection and electric circuits for other abnormal
phenomena.
e) Mechanical faults of compressor
i) Seizure of shaft
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