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Hi,
Would appreciate any advice concerning an ongoing problem with my Liebherr CUN 3033 Fridge Freezer (service code 0907994-00).The freezer temp alarm beeps 4 times at various intervals indicating that it is too warm. Temperature when this occurs ranges between -6.6 and -12C. Pressing the alarm button stops the beeping and after a while the system starts up and returns to normal expected temperature. There is no interval pattern for this alarm, varies between 1 and 4 days.
I do not experience any of the Sensor fault codes as listed on the available “Liebherr CUN Fridge Freezer Fault Codes” document indicated by SF LED flashing in sync with relevant temp LED. However I have confirmed 3 of these codes (1) Fridge compartment air sensor, (2) Fridge evaporator sensor and (3) Freezer evaporator sensor by removing each of the 2 wire connectors, at the right end of the control board, one at a time.
Would like to know if these are the only 3 thermistor sensors on this model and do I need to check each one more thoroughly?There is no ice build up on the evaporator, as experienced previously. This was eventually fixed by replacing freezer evaporator sensor after good advice from Tony R and ELDAR59.
Fan confirmed working when freezer at correct temp.
Continuity of freezer defrost circuit confirmed with a reading of 385 ohms.
In desperation replaced original control board 6113897 with latest 6113980.
Thanks in advance
Stay safe
PeteHave you tried running it in super frost mode and checking the temperature after several hours in this mode ?
Thanks Tony R,
No I have not tried your suggestion so far.
Should I wait for the freezer alarm to sound before trying to run in SF mode or just in normal operation.
I take it I should note temperature at the time and then again after several hours of running in SF mode.
I there a fixed time you would suggest ?If you can wait till it alarms, check the compressor and feel if it is running or not and at what temperature it is, ie cold warm or hot, and if not running put the superfrost on and see if it starts up.
Hi Tony R,
Freezer alarm sounded at -6.9C.
Whilst feeling the compressor, which was between cold and slightly warm to the touch, it suddenly started up!
Next I didn’t cancel the alarm and pressed SuperFrost on.
Within a couple of minutes alarm stopped and temp quickly restored to normal level.
Should I leave in SF mode?Will repeat test next time alarm sounds and hope to switch on SF mode before compressor starts up.
Unless of course you instruct me otherwise.Thanks for you help
PeteHi Pete, from your descriptions, I would fit a new evaporator sensor in the fridge, it will be the green one.
Thanks Tony R,
I will order a sensor as you suggest.
Do you know if the 3 thermistor sensors are the same. When I replaced the Freezer evaporator one it had a value of 4.7Kohms.
Also could you please advise location of fridge evaporator sensor. I know it is the green connector on the control board but so far have only located the fridge air sensor behind the lamp cover housing.
Thanks again
PeteYes Pete all the sensors are the same, the green sensor is behind the panel at the end of the light housing and then screwed to the rear wall.
Regards Tony.Hi Tony,
Replaced theevaporator sensor in the fridge as advised.
All seemed to be OK but unfortunately after 3 days freezer alarm sounded at -7.5C.
Cancelled alarm and pressed SF button, compressor started up after 9 minutes.
Would appreciate any further advice you could offer as possible solution.
Regards PeteHi PClem,
Since I am experiencing exactly the same issues as you with your freezer, I was wondering whether you have any updates on the problem?
Kind regards,
RienHi Rien,
Unfortunately I have nothing positive to update you with following my actions previously reported.
I am lost for ideas to resolve this frustrating problem now as the component parts test out OK.
I fail to understand why the freezer alarm sounds at various different high temperatures and other times works fine.
Was hoping that an experienced engineer on this forum might be able offer some logical explanation.Good luck with your freezer and please let me know if you have any ideas or come across a solution elsewhere.
Regards
PeteHi Pete, sorry to hear your unit is still malfunctioning, they are not that complicated a unit, there are only 4 sensors, 2 in the fridge, air sensor (red) turns unit off at temperature as selected on dial, evaporator sensor (green) which turns unit back on after fridge rear wall has defrosted, the evaporator sensor in freezer ( black) turns the fan on at -25c at coil temperature and ends the defrost phase around +5c, there is a dripping time after the defrost, the 4th sensor is an ambient sensor located on the board, this cannot be tested and you have already fitted a new board. I suspected the fridge evaporator sensor as this is the one that brings the compressor back on, I try and give as much help as I can via this forum, but it can never replace a visit and inspection by an Engineer.
Hi,
Just an update on a couple of symptoms experienced with this ongoing issue of intermittent freezer temperature alarm without any explanation.
When the freezer alarm sounds (4 beeps) if you do not cancel it by pressing the flashing red alarm button it stops after 30 minutes and unit eventually returns to normal operation.
If the fridge door is left slightly open with light off alarm (3 beeps) never sounds?
If opened further to bring on light alarm sounds correctly after 60 seconds.
Freezer door is left slightly open similar to fridge door alarm never sounds.
Would appear that door open system alarm relates only to operation of relevant reed switch and nothing to do with temperature of either compartment.Any comments welcome.
[h=2][/h]Hi Pete,
Door has to be open by more than 2 mm to activate door open alarm, 3 beeps. Going back through the threads I can only suspect the evaporator sensor in the fridge, this is the ONLY sensor that activates the control board to fire up the compressor, there is no actual control of the freezer, the temperature of the freezer is controlled by the fridge sensors, red air sensor, turns the unit compressor OFF, fridge evaporator brings the compressor back ON, once the fridge rear wall has defrosted, evaporator sensor in freezer coil ends the defrost and brings the fan back ON when refrozen. You say the compressor was warm to cold to touch which tells me it is not struggling to start when required, so something is keeping it OFF, which leads me to the fridge evaporator sensor, I assume you fitted a genuine Liebherr part.Dear Pete and Tony,
I seem to have a similar problem with my Liebherr CUN3033 fridge freezer. It’s 4 years old and for a few months has had a 4 beep alarm intermittently for high freezer temperature. I’ve changed the settings lots but manually checking the temperature it stays -10ish deg regardless of changing the set temp to much lower. There is also ice build up on the freezer back wall. The fridge side works just fine. I’ve cleared the ice but it accumulated again. Is this a freezer evaporator sensor malfunction? I can see a cream coloured sensor right in the middle of the back wall of the freezer. Rear wall fan in freezer works ok.
Any help is much appreciated.
Thank you in advance
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