Samsung RT50K6335SL Top Down Fridge Evap Coils Freezing

Refrigerator & Freezer Repair
1

Brand: Samsung
Model Number: RT50K6335SL
Main Symptom: Coils Freeze up after a few months
What happens & when:

Hi all,

So over the past year to two years, my evap coils in the fridge portion of my unit freeze up enough to affect the fan. It makes a loud grinding noise as the fan is hitting the ice build up. If I leave it alone, the sound might go away for a day or two, but it comes back. If i leave it too long, the fridge eventually starts to heat up.

My solution (based on youtube videos) have been to take off the evap cover and use a steam cleaner to melt all the ice build up. I put it back together and all is well. 3 or 4 months later, same issue.

I’m about to go the path of testing the thermistor, however one thing I noticed is that the fridge portion of my unit doesn’t appear to have a heating/defrost element. I can’t imagine this was left out accidentally, so are some Top/Down fridges like this? I assume the heating element is located in the top freezer part (I found some service manuals for Samsung fridges that are similar to my model - and they only specify a heating element in the Freezer).

That being the case - i wonder how the heck the fridge is able to defrost the bottom part appropriately?

From what I can see is there are two thermistors in the fridge (bottom part) - one located on the coils, and one (I assume) is located within the evap coil cover (I see a yellow wire running under the evap fan, and based on documents I assume this is it.

My next step is to clear out the freezer part of the unit and see how that looks - if it’s a solid block of ice, or maybe the drain for that is blocked. I don’t know. It’s just confusing as all Youtube videos for Samsung fridges are ‘french door’ style - which appear to have a dedicated heating element for the fridge portion, however they have freeze issues as well.

Any help would be greatly appreciated. I’ll include some pictures.

Error Code (if any): N/A
Parts or tests already tried: N/A
Photos / video link: Imgur: The magic of the Internet

2

Many of the refrigerators now days do not put a heating element in the refrigerator due to the temperature is above freezing. when the refrigerator sensors reads the proper temperature it shuts off the fan and freon going to the evaporator. This allows the frost that was formed on the coils to melt off naturally. If the coils are freezing up, the temperature in the refrigerator is either set too cold, or the sensor is reading the wrong temperature and is staying on too long.

3

Thank you taking the time and responding. That’s really good to know and makes sense in the context of my issue. When this first started happening I put a IOT temp sensor in the fridge and confirmed it was at least cycling. I have the fridge set to 2c - so I’m assuming that is too low. I imagine the evaporation coils need to be colder than that to get the ambient temperature to 2 Celsius. I’ve put it up to 4 and will monitor.

thanks again.