I have recently had an issue with icing up in the refrigerator or a Samsung RS21 NCMS,which has resulted in the fridge being too cold and reaching -6C. I found that the R fan was iced up and the motor had burned out. The motor has now been replaced.with a genuine Samsung replacement motor. The fridge was completely thawed out and all ice removed, and the lower panel defrosted so no ice or water remained.
When I switched back on the diagnostics passed without any issue and no errors were displayed. After about 4 hours of operation, I ran the diagnostics again and no error was displayed. The Load check had segments 6, 8 , 10, 13 and 14 displayed.
After a total of 24 hours since switching on the refrigerator was cooled to around -5C. Changing the Fridge Temp on the control panel made no effect to the fridge temp which is now cycling between +4C and -5C with the display set at 7C. I re ran the diagnostics and segment 4 was displaying as an error code. The fridge motor is running and the voltage v=being supplied to it is approx +10V dc and the feedback is supplying +2.3V dc. THe laid Check is the same as before with segments 6, 8 , 10, 13 and 14 displayed. I found that changing the Set Point Shift for the fridge also made no difference. I can see nothing in the service manual that helps any further with diagnosing this problem.
I have replaced the fridge thermistor with a new part as it was not reading correctly when tested, but the results are still the same.
The freezer is behaving perfectly.
Do you have any ideas on what could be causing this and what I should check?
Is it possible to use a DA41-00188A controller with the RS21NCMS model as it does not have all the additional features? Would it just work as expected but produce error codes for all the features that are not present?
I look forward to hearing from anyone who can help.