Control Principle Of The Air Escaper; Control Principle Of The Fan; Defrosting Control Principle; Refrigerator Test Model - Haier AFD631 Service Manual

ELECTRICAL CONTROL PRINCIPLE

8.3 Control Principle of the Air Escaper

（1） The refrigeration air door is controlled with the fridge storage temperature sensor R SNR.
（2） The air door is closed from the beginning of defrosting until 15 minutes after the defrosting is
finished.
（3） Upon initial powering on or resetting of the control panel, the air door conducts a
close-and-open cycle before acting according to the control conditions in item (1).
（4） The air door will be forced to conduct an open-and-close cycle if it has been closed for 1 hour.
After that, its closing/opening will be controlled by R SNR.
（5） If the temperature is still rising (or dropping) within 10 minutes after opening (or closing) of
the air door, it will open (or close) once again.

8.4 Control Principle of the Fan

The freezer fan is controlled by the control panel according to the following conditions. The DC
fan's rotation speed is regulated with PWM mode and the AC fan operates directly.
(1) ON/OFF condition of the freezer fan (The control mode of the DC fan is listed in the table
below. The AC fan runs under condition ON and stops running under condition OFF):
（2）When the fridge storage compartment door is opened, the freezer fan will run and the
refrigeration air door will open. After 2 minutes, the refrigeration air door will close;
(3) When the freezer storage compartment door is open, the freezer fan will not run;
（4）Conditions for judging LOCK of the freezer fan: If the rotation speed of the fan is less than
300RPM or the fan does not run and the state has persisted for over 30 seconds, a freezer fan
malfunction will be displayed. Normal display will be recovered after it becomes normal. Otherwise
the freezer fan malfunction will persist.

8.5 Defrosting Control Principle

A defrosting cycle will be started once the compressor has operated for 8 hours accumulatively. It
will stop defrosting when the defrosting sensor detects a temperature over 10ºC
The compressor stops and the refrigeration air door is closed during defrosting.
After initial powering on or resetting of the control panel, it will start the first defrosting cycle after
the compressor has operated for 6 hours accumulatively.
It may enter the defrosting state when the defrosting sensor is malfunctiony (short-circuit or
open-circuit). In this case, it will exit the defrosting state after 30 minutes.
8.6 Refrigerator Test Mode
TEST1：Press the TEST key on the power board to enter the〈PULL DOWN MODE〉, the door display
panel displays T1 T1 and the refrigerator enters forced refrigeration state: the compressor
operates normally, the fan runs at high speed, and the defrosting heating wire is disconnected.
This can be used to test the refrigeration performance.
TEST2：Press TEST key again in TEST1 MODE to enter the 〈FORCED DEFROSTING MODE〉. It
will act depending on the temperature sensed by the defrosting sensor
When the temperature sensed by the defrosting sensor is over 10℃, the heating wire will exit
the 〈FORCED DEFROSTING MODE〉after 20s' heating
When the temperature sensed by the defrosting sensor is below 10℃, the heating wire will heat
continuously until the temperature sensed by the sensor reaches 7℃
In the 〈FORCED DEFROSTING MODE〉, the door display panel displays T2 T2, the
refrigerator conducts forced defrosting, the compressor and the fan are turned off, and the defrosting
heating wire is turned on. At this moment, you can test the power of the defrosting heating wire and it
should be 153±15W.
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