Solved: Fridge Freezer (RSG5UCRS1) not holding temperature - Page 4

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 · ‎06-05-2023

Hi Robert - is your freezer still working fine?

I decided rather than wait to defrost it, pull it all apart and then do all the continuity checks on the thermal fuse and impedance on the defrost and drain heaters, I would order the defrost sensor first and when it arrives I can do all the checks and replace the sensor if that is the problem without having to wait for it to be delivered. If I have guessed the wrong faulty item it's only £10 wasted but it means I dont need to have the fridge and freezer off line quite so long.

Sensor has now just arrived so as soon as I have runs down the frozen food I will dive in - any last minute pieces of advice??

Regards, Mike

Nontechmile · ‎06-05-2023

Hi Robert

Is your freezer still working?

I thought to try and minimise the time my fridge freezer is off line, I would order the Sensor first and then do the defrost, perform the continuity test on thermal fuse and impedance checks on the defrost and drain heaters and then check the defrost sensor. If it turns out my guess was wrong then I wasted £9 but if I was right it speeds things up.

Sensor has just arrived so as soon as I have run down the freezer contents I will dive straight in - any last minute words of advice/wisdom??

RobLexy · ‎06-05-2023

Hi Mike, it’s a story with a sad ending unfortunately. Replacing the defrost sensor did help as the automatic defrost system began working again. However, now when the defrost heater came on, it would stay on for far too long, causing the freezer temp to rise to +5 degrees. The heater was coming on for an hour rather than the expected 20 minutes or so. I then tried fault finding on the control board pcb, but before I could make any progress, the freezer defrost heater failed completely. This is effectively a non replaceable part so that was that. I accepted defeat and bought a new samsung fridge freezer (basically the same one but 24 years younger).

I continued to use the temperature data logger in the new freezer and the result may surprise you. Going by the graphs you shared in this thread, you are seeing temperature fluctuations around -20 and then every few hours a rise to approx -14. Well that is precisely what is happening with the new fridge freezer. I guess I’m suggesting that there may be nothing wrong with your freezer at all. If you are only getting temp rises to approx -14 then there probably isn’t a fault. With my old one, the food was defrosting so there clearly was a problem.
Is -13/14 the warmest yours gets or does it get warmer than that?

Nontechmile · ‎06-05-2023

Well Ive been playing around with where I position the data logger sensor. With Freezer set to 20°, to start with it was seeing background variations of about +/- 1° with large increases every 9hrs apart. The first one being upto around -17° followed 9 hrs later by -13° and then 9hrs after that back to -17° and then 9 hrs later still -13° with this pattern then just repeating.

But then I moved the sensor right to the top of the freezer and then I got background variations of +/-4° with the highs still repeating every 9hrs but now with an initial high of -14° and then a high of -5° !! With the sensor right at the top where the "air" comes in I guess it is more sensitive to the incoming air temperature rather than the average ambient internal temperature of the freezer as a whole. So when the Freezer is trying the defrost it picks up on the incoming warm air and then when it is trying to cool back down it picks up on the extra cold air going in. Well that's the best theory I can come up with to explain why position of the sensor has made such a difference.

So I am going to move the sensor back down to the middle of the freezer for a few days and see what happens then.

Hopefully we will then be back to seeing the short period highs of -14° interspersed with short periods of -17° with the freezer otherwise running at -20° +/- 1° and if that is the case then maybe I stop worrying about it.

We had become sensitive to freezer temperature and monitoring it as a result due to one occasion when food defrosted - we were advised to do a 48Hrs defrost which although sceptical we did and since then this problem does not seem to have repeated itself. But we had lost confidence and got nervous when we saw large temperature variation even when they were very brief. But maybe what you have seen with your new freezer is that this is normal!!

Nontechmile · ‎06-05-2023

PS. Just out of interest which new model did you go for?

RobLexy · ‎06-05-2023

I can understand why the increases to -14 would be a concern, but the user manual of my new one explains that there is a variation in temperature due to the defrost system. Also the display temperature never changes from -20, just like yours - presumably deliberate as to not cause customer complaints of a fault when it is simply defrosting itself.
My replacement is model RS50N3913BC, which does everything the old one did but uses half the electricity. I insist on having plumbed water supply and a homebar so the choice on the market is very limited. Very pleased with it.

Nontechmile · ‎12-05-2023

That model isn't available in the UK but it looks great - I bet you're please with it

So I have powered down and defrosted mine and taken the internal back cover off the freezer compartment. I think the connector arrangement is slightly different to yours. Not sure but I think the sensor is in the top position, one of the heater wires is in the middle position and the thermal fuse connected to the bottom position. The second heater cable is on its own connector. See pictures

My sensor seems fine at room temp - shows 6k (my replacement sensor is showing more like 5.7k) but I guess that means the sensor is OK after all.

When I check impedance between the 2 wires of the Thermal fuse it shows effectively short circuit - I assume this is correct

But how do you check the impedance of the 2 heaters. I can put one probe on the single heater wire but where do I put the other probe?

RobLexy · ‎12-05-2023

It is a UK model and I am in the uk, I suspect I got one of the last ones as its been on the market for several years. I was limited by choice as I needed that homebar and plumbed in water.
Re your pics, I agree the temp sensor will be top, resistance looks ok, thermal fuse probably the bottom one and yes, you want continuity/short circuit. The middle connector has a single brown wire as it looks to me. So test the resistance between that brown wire and the other brown wire in its own connector. The resistance should be 100-350ohms approx. Just not 0 or short circuit.
My old one had a drain heater connected in parallel with the defrost heater. Yours perhaps doesn’t have a drain heater? (Red wire laid out around the drain hole.

Nontechmile · ‎12-05-2023

Impedance between the 2 brown wires is 0.2k. Given your comment above this 200 ohms sounds right. So I think that means all those items are OK. Maybe as your new machine has demonstrated briefly going upto -12/13° every 16-18hrs with a less severe increase to - 16/17° half way in-between these occasions is "normal". Latest datalog attached (we were away towards the end of this log and so no door opening and closing which might explain why we didn't get the "in-between" event on a couple of day). Of course I dont know how accurate the calibration is on this data logger - we have the freezer set to -20° and the chart shows an average more like -21° so may be we are reading 1° low? Either way I think I'm tempted to stick with it for now and just monitor to make sure we dont get any extreme hot events going forward

Thanks for all your help and advice. It was very much appreciated.

Regards, Mike

RobLexy · ‎12-05-2023

Hi Mike, looking at your latest charts and knowing what we know now about how the new one behaves, I think you can be confident there is nothing wrong with yours. So that’s a good result for you. The temperature rise with my old one was extreme and food actually defrosted. I’m still a bit disappointed I couldn’t quite fix it completely. I feel like a doctor who lost a patient on the operating table. Anyhoo, another 17 years and the new one will have paid for itself in electricity cost saving so there is that.
Best wishes to you and your fridge freezer.

Rob