Midea HC-702WE - Chapter 6: Flow Chart of Refrigerator Failure Predication

8
Chapter 6: Flow Chart of Refrigerator
Failure Predication
● For different products, there is some difference for the predication of failure, thus, it is un-necessary to
explain each point clearly.
● For products with inleakage and in need of repair, excavate the foaming material according to the
pipeline location drawing in Chapter 3. Carry out repair welding for the inleakage point, and conduct
pressure maintaining and leakage detecting. No leakage found, fill it with foaming material.
Figure -1
Use oscilloscope to
check whether
signal is output here
abnormal operation
of refrigerator
check the power
supply and voltage
electroless
too low voltage
check the
plug and
socket fuse
check indoor
power circuit
normal
The compressor
can be started and
operated normally
Whether the display
displays normally,
whether there is
trouble code
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
no
no
no
no
no
no
no
no
no
Firstly, eliminate the
trouble according to
the trouble code
and instruction.
no
See Figure-4
See Figure-5
See Figure-1
See Figure-2
See Figure-3
The
compressor
fails to start
display and light
off
display and light on
check the
power line
Use the oscilloscope to
check whether there is
signal sent out from the
main control panel
poor refrigeration of
chilling chamber
poor refrigeration
of refrigerating
chamber
Whether the chilling
chamber blower fan
works normally
Whether the
refrigerating chamber
blower fan works
normally
Whether the chilling
chamber defrosting
heater is normal
Check the chilling
blower fan circuit
or change the
chilling blower fan
Whether the
refrigerating
defrost heater is
normal
Check the refrigerating
blower fan circuit or
change the chilling
blower fan
Check the heater
circuit or change the
chilling chamber
defrosting heater
Check whether the
electric changeover
valve works normally
Check the heater
circuit or change the
refrigerating defrost
heater
Check which one is
larger, the compressor
power or the rated
power
smaller
smaller
larger
larger
Check the electric
valve circuit or
change the electric
changeover valve
Check which one is
larger, the compressor
power or the rated
power
There is insufficient
coolant in the
system, and refilling
is required
There is insufficient
coolant in the
system, and refilling
is required
The system pipeline is
blocked up. Find out
the blocking point,
weld and refill again
The system pipeline is
blocked up. Find out
the blocking point,
weld and refill again
abnormal operation
of the
temperature-variabl
e chamber
whether the
temperature of
temperature-variable
chamber is normal
on the high side on the low side
the temperature-variable air
duct is blocked up or the
temperature- variable
damper is not open
temperature
-
varia
ble damper opens
all the time and
cannot be closed
clear out the foaming material in
the temperature-variable air
duct, or check the damper
circuit and change the
temperature
-
variable damper
change the
temperature-vari
able damper
poor refrigeration
of the chilling and
refrigerating
chamber
whether the chilling
chamber blower
fan works
there is no sound of
flowing coolant at
the inlet of
evaporator
check the
condensate fan or
change the blower
fan
very low power
dissect the process
tube after closing
down
master control
board trouble
change the
master control
board
check whether there
is voltage output from
the frequency
conversion board
check whether the
frequency
conversion board
and compressor
connector are
correctly erected
frequency
conversion board
trouble
change the
frequency
conversion board
wrong terminal
linear ordering may
cause compressor
trouble easily
compress
or trouble
change the
compressor
change the
compressor
change the
compressor
there is
no
liquid ejected
there is liquid
ejected
all the coolant
is leaked
find out the
leakage point,
pump out and
refill the coolant
restarted, there
is no suction at
the cutting
nozzle
restarted, there
is suction at the
incision
compressor is
out of work
there is blockage on
the high voltage side
clear the blockage,
evacuate and refill
the coolant.