Samsung fridge section of fridge/freezer keep icing up

Hi all,

A year ago, we brought a house, and as agreed, the previous owner left behind their American style Samsung fridge/freezer as part of the sale. I estimate it to be about 10 years old. The fridge is a frost-free type, as you know, it uses a fan to draw air from the cabinet, pass it through a cooler, then back into the cabinet. If the temperature of the cabinet went above a certain limit it would sound an alarm. If the door is left open, an alarm sounds. There are 2 temperature displays outside on the door showing the temperature of the fridge & freezer. Please forgive me for not using the correct technical words.

After a month of moving in the house, I found the fridge not very cool, found that the air inlet had been iced up, took the back of the inner cabinet out and took 4 hours to de-ice everything inside – there were so much ice – cleaned everything thoroughly, checked the fan worked and put it back together. It worked perfect after. I set the thermostat to 2 degrees C. The freezer was fine, no problem at all. This was less than a year ago.

Recently, I found things started to go off quickly, milk would go off after 2 days of purchase, things would go mouldy quickly. The fridge thermometer display on the door showed 2 degrees C and no problem. I borrowed a stand-alone thermometer used in a different fridge it showed 13 degrees C.

I had a look at the inlets, it was badly iced up again.

I will take it apart to remove the ice. The stand-alone thermometer showed that the freezer is at the correct temperature as shown on the door. I assume the sensor for the door thermometer display is within the back of the fridge behind the iced up inlet so that is probably the reason why it is unaware something is wrong. However, I’m just guessing here.

I need to know why does it ice up so easily? How can I prevent it from icing up again? I know the fan works fine. However, I can’t tell if the self defrosting process works – I assume it heats up the cooling circuits by reversing the process? I know leaving the door open for too long and too much will create condensation which will ice up the heat exchanger, but my wife and I am quite good about making sure the door’s closed, and we rarely leave it open for too long.

Any advice would be greatly appreciated!