Solved: Fridge Freezer (RSG5UCRS1) not holding temperature - Page 3

Nontechmile · ‎19-11-2020

Although display says both fridge and freezer are at the requested temperature they are not. I have checked with a separate fridge freezer thermometer. If a do a reset (turn it off for a few minutes) the temp display now shows the correct temperature (albeit only about -6 in Freezer and 9 in fridge) but then slowly shows both temperatures reducing towards the set temperature (-19 Freezer and 3 for fridge). However, when I check the temperature manually it is still way too warm - another reset and the display again shows the correct temperature. So bottom line is the fridge freezer seems to think it is achieving the asked for temperatures but in reality it is not.

I have had it 8 years - it is still in same location it has always been. All door seals look good. All other functions (eg ice making) seem to be OK. No build up of ice inside the fridge or freezer. Any suggestions as to probable problem - fan, compressor, thermostat, coolant leak, mother board controller, etc??

PS. What is the warranty on the Compressor - I seem to recall it was 10 years.

Nontechmile · ‎18-04-2023

I have everything crossed for your success - I was just about to bite the bullet and buy a new one but will now wait to see how you get on. Good Luck!

I have installed a temp tracker probe inside my freezer to see what is actually going on over time. I can see that I get elevated temperatures every 8-9 hours. First is a very high temp of around -14° and the second event is around -16° . There appears to be a small drop in temp just before it goes to its highest temperature. Although the absolute temp may not be accurate I think we can rely on the variations in temperature it shows. Right at the end of this recording you see I did not get the high temp spikes - we were away for a couple of days and so the freezer was never opened during that time. Once we got home and started using the freezer again the 2 temp spikes started up again. I have attached one of the charts to show this.

Is this in line with what you are seeing and do you think the defrost sensor replacement will do the trick for me too?

PS What did you search for on eBay?

RobLexy · ‎18-04-2023

Yes, I think what you are observing is the same problem I have. You are seeing the fridge going into manual defrost mode every 6-8 hours, because the auto defrost has not been able to run. Although we have the same problem, the solution may not be quite the same and I’m long enough in the tooth not to declare success too soon. My freezer defrost sensor (search for 502AT samsung defrost sensor on ebay), the one with yellow wire, is way out of tolerance, resistance at room temperature of 1.2k ohms which translates to about +40 degrees! It should be about 5.7k ohms at room temperature. The fridge would only detect a fault if it reported >50 degrees or fails full open/closed circuit. It’s certainly possible that your defrost sensor is a problem, are you able to check with a multimeter?
I will know a bit more in next few days and update here. I’d love to think a £10 component could rescue what is otherwise a fantastic fridge freezer, but we’ll see…

Nontechmile · ‎18-04-2023

Thanks for getting back to me so quickly.

I do have a multi meter. Could you tell me more about where to look for the sensor and its connections?

RobLexy · ‎18-04-2023

Update: New Freezer defrost sensor arrived. Fitted it and good news so far. The fridge successfully completed self diagnostics. I ran it in forced operation and was able to confirm the fridge and freezer defrost circuits working (by monitoring power consumption using a smart plug). So now its just a case of monitoring temperature over the next day or two.
The photo shows inside of freezer. Unplug connectors (circled in red) and with a multimeter : top connector is thermal fuse - check for continuity, middle connector is defrost and drain heaters - test them for resistance individually. Should be several hundred ohms but not open or closed circuit, bottom connector is defrost temp sensor- resistance should be about 6k ohms at room temperature.

Nontechmile · ‎18-04-2023

OK thanks. I had not realised they were behind the internal back face of the Freezer. Presumably its fairly obvious how to remove this cover once I have run down the food in the freezer and taken all the shelves/drawers out.

Id be keen to hear how the extended trial run goes but sounds hopeful so far.🙂

RobLexy · ‎18-04-2023

There’s 2 ways to check. Either by removing furniture and panels in the freezer/fridge compartments or by the connectors at the pcb. Neither way is easy but if any parts need replacing you’d have to disassemble freezer/fridge compartments anyway.

I would recommend finding a copy of the service manual online to guide disassembly. I found mine on elektrotanya.com. Photos below show method for testing at the pcb end.

Nontechmile · ‎18-04-2023

Thanks again. I tried the site you said plus a general Google search for a Samsung RSG5UCRS1 Service Manual but without success. Lost of User Guides and Instructions but no Service Manual. Happy to share my email with you if you are willing to share your copy?

RobLexy · ‎18-04-2023

I’m happy to email my service manual to you but just beware they are very specific to the models, but very similar nonetheless. Also I got caught out looking for the wrong model number. There is a sticker on the outside left wall with a model number which got me nowhere. There is also a sticker on the inside of the refrigerator door about half way down. That model number is different and with that I was able to find the service manual. Don’t ask me why it would have 2 model numbers!! Lol

Nontechmile · ‎18-04-2023

RSG5UCRS is the model mentioned inside the refrigerator door

If that matches yours then please fwd to mjss_ivellatmsn.com (you'll need to replace the at with an asperand symbol)

RobLexy · ‎18-04-2023

I am beyond excited to report it is FIXED!!!!! Hurrah!
So this happens now:

Power on from room temperature. (Power consumption 180w)

Compressor runs for 4 hours.

Compressor Off. Freezer and Refrigerator heaters On (400w) for 10 minutes.

Refrigerator heater Off, freezer heater remains On (245w) for a further 15 minutes.

Everything off for 10 minutes (2w)

Compressor On AND temperature display updates itself (1 degree temp rise) and resumes cooling. (180w)

The root cause in this case, was a failing (NOT failed) freezer defrost sensor. As the sensor had not completely failed, it passed the diagnostic checks and confused the hell out of the control board, so it refused to enter auto defrost cycle and would go into manual defrost cycle every 8 hours causing temperatures to rise in fridge and freezer. The worse it got, the worse the temperature rises got and eventually my freezer food was defrosting.

My 24 year old Samsung fridge freezer has been rescued by a £9 sensor. Happy days.