Can i hold down some buttons or check somthing to give me an idea what may be wrong? fridge seams to be working ok

top of display shows a square to tell me there is a problem

Peter, September 2005

when i open my door on my aeg santo rs18031 the display is flashing but temp is ok

anthony, April 2011

Adding to Bruce Gridley's answer the black cabled sensor can be dried out if it fails by removal and placing somewhere fairly warm for a while. While it is missing I substituted a variable resistor set to just over 7K as that was the value I measured when working (6K8 may do). I have left this for several months but eventually the fridge went warm warm, guessing the software controlling the defrost is waiting indefinitely for the evaporator to warm up and the sensor resistance to fall (unless my fridge has some other fault making it stop). Changing resistance to around 3k5 (warm value) gets fridge going, then change back to 7k. I have only done this once so far but seems to work. Beware this circuit floats at a high ac voltage so switch off when working and use a two wire flex joiner to house the resistor safely.

pj, February 2011

Hi Dr Michael S Short,

How old is your fridge if you now need to defrost it every 2 weeks?

Regards
Leon

Leon, December 2009

This is an addendum to my orginal answer:
As the fridge gets older the problem appears to happpen quicker. My Santo fridge now requires a complete manual defrost (taking several hours) every two weeks. I have pondered this and consider it to be the build up of an oxide layer on the aluminium fins.
When the unit is new the aluminium is clean and un-oxidised. The surface tension effect is materially altered as the oxide layer forms increasing the amount of water held up at the gap between the fins.

Dr Michael S Short, June 2009

so where can I order that part from ? Ive done a search on the aeg website for part no 2080861058 to no avail. we have same problem! help!

cinderella, December 2008

Bruce Gridley here again the sensor was changed £18. and still working brilliant, It was the only spare sold by espares so that must be it , it was next time I'll do the same maybe?!

Bruce Gridley, December 2008

The temperature sensor at the evaporator is defective due to the humidety. The sensor is behind the radiator at the rearside of the fridge.Remove the power plug first !! Remove partly the radiator at the backside carefully and the putty at the hole in the backside. Pull out the sensor with the blackwire. The sensor with the white wire is the one inside the room of the fridge. The partnumber is 2080861058. It is a common problem of this type. By replacing the sensor it has to be not to far pushed inside the tube (to the first lock)
Connect the sensor wire of the new sensor to the wire of the old sensor with a wire connector, otherwise you have to dismount the control panel every time. The normal live of the sensor is only one year ! Good luck.

johan, September 2008

Would switching it off and leaving it to defrost itself for 2 weeks do the same job? (while on holiday). Does the square on the temp guage correct itself after removing the ice or is that a faulty sensor problem?

Margo, June 2008

It is all to do with the surface tension of water.

The design of the fridge is basically a fan to blow the fridge air over a finned cooling heat exchanger set vertically down the centre back of the fridge. The cooled air then comes out at various points down the fridge to maintain an even cold temperature.

After a time, the fridege goes into defrost mode to melt the ice build up on the heat excanger and under gravity the water runs down and out of a drain pipe located directly below the heat exchanger. So far so good

Unfortunately, in order to get good air cooling the heat exchanger has lots of fins closely packed together set along the vertical coolant pipe. (The fin spacing is only 2 to 3 mm.) Therefore the fins are not very far from horizontal and very close together. This means that although the ice melts the water does not completely run off from between the fins. A small quantity is held by surface tension along the bottom space between successive fins when the defrost cycle finishes.

This water refreezes and is of sufficient quantity not to melt in the next defrost cycle. Indeed each cycle causes a little more ice to build up. The fridge therefore works for some months without a problem but eventually the heat exchanger becomes a solid block of ice touching the plastic cover plates whereupon ice starts to form on the front of it.

Removing the ice from this section will not cure the problem. You need to remove the plastic cover sections to gain access to the heat exchanger behind them and pour boiling water over it until all the ice (AND WATER) is removed from between the fins. In total it took me several hours.

Remove a narrow plastic strip at the top using a small screwdriver in one of the small holes. Then remove the screws to take off the top cover section. Pull towards you on the left. You may find it difficult because the ice build up prevents getting the plastic plate out on the right hand edge. Do not force it and be patient. I did not have any, but windscreen de icer sprayed behind the plastic, especially on the right hand side will help speed up the melting. A hair drier set to warm not hot will help to remove all the moisture at the end.

As soon as ice starts to show on the front of the plastic panels the job will need to be repeated. However if you have removed all the ice and dried it it should last as long as it did from new.

Dr Michael S Short, May 2007

Brian B.
Would love to know how you got on with the ServiceForce centre as I am at exactly the same stage and dependant on your reply may throw the fridge away and replace it. HELP!!!

Gary, March 2007

I have a problem also with santo 3795 -7kg Fridge part, top suare showing. The fridge freezes almost, ice at back and no defrost cycle. It was intemittent and had fixed it for two periods of several weeks. have tried checking thermostat and soldered pCB and checked all connections to no avial. Disheartened but as electtronic engineer frustrated there is no further info or self check known to me. Changing the thermostat would destroy the fixing. I have already routed cables dircetly to PCB to isolate poor connections. Still no fix!

Get PCB serviced on web page there is a company doing it for £32-34, not sure if they do AEG or this one though. else buy new fridge , not AEG!

Bruce.

Bruce Gridley, October 2006

I have the same problem & suspect the thermostat is faulty. Does anyone know how to locate & change it

Brian B. Leighton Buzzard, January 2006

We have the same problem. The manual is pathetic. "If the display shows a rectangle instead of the temperature, then there is a problem with your fridge."

And that's all it says! Anyway, our fridge is turning into a freezer - we have to leave it on for 12 hours, then off for 12, otherwise everything is 80% frozen. Doesn't make a difference what we set the temperature to.

So, basically, the rectangle means there is a problem, but nothing specific. Called the ServiceForce centre, they were meant to come on Saturday but didn't turn up, now they're telling me January 16th before anyone can come!

Chris, December 2005

Do you have a problem with water coming out of the fridge.

If so that ligt and the water coming out is the same problem i have and I have been quoted £200.00 to fix!!

Any ideas on a cheaper fix?

James, October 2005