P a g e
21
PRINTED : JAN’2015
REF NO. SM7715010-01-11
7. Defrosting control
Item Explanation
Outline
Defrosting starts based on compressor operating time.
Execution period
Accumulated time of the compressor operating
Minimum time
8hours
Original value
* First defrosting from power supply ON
Ambient temperature 34
o
C or over: 8hours
Ambient temperature less than 34
o
C: 12hours
* After the second
Ambient temperature 23
o
C or over: 18hours
Ambient temperature less than 23
o
C: 20hours
Shorten the execution
period by R door
OPEN/CLOSE operation
The execute period becomes short 5min by door opened every 3sec.
But,
* Ignore less than 20sec operation per 1 time
* It isn't becoming below minimum time.
* Maximum time is 100min by 1 time operation
Conditions of
shorten the execution
period to minimum
* When defrosting process continues for 40min.
* When the compressor continues ON for 1.5hours in normal cycle.
* When the compressor continues ON for 3hours in first time after
defrosting.
End judgement
8.0
o
C (D sensor temperature)
Control before defrosting
When accumulated time reaches fixed value, compressor and freezer
fan operate to compressor OFF temperature.
Next, defrost heater output shall be started.
(For details, refer 8. Compressor/Fan motor control before defrost)
Maximum time of
defrost heater output
90min
Manual DEF
When MDEF pin
（
CN12
）
is shorted, execute defrosting process
Immediately.
When sensors are
abnormal
When R sensor or D sensor are open or short, the defrost heater shall
be
forced OFF.
8. Compressor/Fan motor control before defrosting
Item Explanation
Outline
When defrost condition is realized, compressor and freezer fan control
are changed.
Step1
When accumulated time reaches fixed value, compressor and freezer
fan
operate to compressor OFF temperature.
Next, do Step2
But, in spite of that it doesn't reach compressor OFF temperature, when
the compressor continues run for 45min, proceed to Step2.
Step2
The compressor shall be turned OFF, and start defrost heater output.
