Aeg favourit- water not heating up

AEG Favorit 40850 Problem : Water not heating. Solution : Checking the heater Access to the heater (tube type) is via the small rear panel. Remove two star screws, and pull the sides out SLIGHTLY to release the panel. The electrical contacts of the heater are to the inside so are not visible yet. I removed the left hose (hose compression clip) and the earth connection on the bottom of the heater. This allowed me to twist the heater round and see the electrical connector. I removed this, and measured the resistance of the heater. It was 28Ω, from reading various forums, this seems to be of the correct order, therefore the heater is ok. I put everything back together, remembering the earth connection on the bottom, and turned to the front of the machine Checking the Relay : Again from reading around there is a relay in the supply chain to the heater, described as ?in the door?. I opened the door and removed the crosshead screws. This released the front panel from the inner metal part. The control switches and the mains switch are held in with clips, easily removed, I guess you could leave the mains switch connected to the front panel, but I removed it so that the skin would not be pulling on any wires. I then wrote (with an indelible pen) a number on all the connectors to the control box, noting that one of them has to be fitted at one particular end of the unit connector, as it could fit in more than one position. With the control unit removed the next step was to open it up. The control unit is clipped together with four clips, just press them in and it opens. At this point I should say that there are proper electronics inside this box, so some sort of static protection should be observed! Ground yourself before working inside the unit, touching something metal connected to ground should to the trick (radiator, but not the painted part!), and do not touch any of the components on the board, or the connections. Be careful of the flexible connection between the two boards, do not bend it any more than necessary. The relay mentioned above is in the bottom left of the board in my extremely bad picture. Unclip the main board, and have a look around where the relay is on the other side. One of my pins was charred, and on closer inspection was not actually making contact!! Looks like it was a bad / high impedance joint that was getting hot, and finally melted the solder causing the open circuit that made the heater not work. With a soldering iron I reflowed the solder (adding more as necessary) to make the connection between the relay pin and PCB good. This was the only visible problem, so I reassembled everything (reverse order of disassembly, Haynes is a wonderful manual!!!) and tried the machine. IT WORKED!!! The whole process took probable less than an hour, and saved the cost of a repair man, and a new control unit (I don?t think anybody fixes things like this on a commercial bases any more, easier for them to just replace the unit!! This is what I did to fix my water not heating problem, I am experienced with electrical and electronic components, so if you choose to follow my story please be careful, it can save a few pounds, but it?s not worth risking your life if you really don?t know what you are doing. For interest, the relay is a NAIS device, numbers on the top are JS1-B-12V-F-H111, and AJS1311F MO1. My relay was working so I didn?t need to look for a replacement, but they should be fairly easy to find if yours is broken. Being an electromechanical device this is probably the most unreliable component in the heater chain, although if the rest of the circuit is designed correctly should last for years, if not decades. (I have seen relays used in gas boilers that had no suppression, and therefore burnt themselves out within 3-4 years, but I don?t think that is the case here)

I had the same problem, water had not been heated..

I went through the Bulgaria´s hints. I am very grateful Bulgaria´s good job, many thanks to him!

I omit checking resistance (functionality) of heater itself because of my believe in problem location in control unit - to avoid a need of washer manipulation itself.


I would like to add some hints.

First. The removal of front two parts door cover is three-four hands job. Top part is with little tingue fixed to bottom part. That´s why you should only loose bottom part screws first, then free top part from frame completely and then fix bottom part again temporarily. That´s time to click switch and control unit plast boxes off from top cover part. Than, you free cables more with removal of bottom part cover. Styrofoam piece under bottom part could be removed or fixed with adhesive tape.

Second. To free control box you should pull the connectors out. When I grounded myself (static charge) I opened control unit box first and I pressed connectors from their possitions by fingers with caution. I decided this way to avoid risk of breaking connectors and/or wrench cables in case I pulled them.

Third. Eye inspection to printed circuit was the textbook one, Bulgaria had mentioned about. There was charred joint there. It was impossible to resolder relay pin to charred joint, every next try to do it would go to next unproper connection (drop of soldering tin instead of small „roof“) and degradation of printed circuit. The solution was short fine wire, one side soldered to relay pin itself, second side soldered to joint before charred field, the relay contact is surrounded by. This is only other, more safe way of reconnection, Bulgaria said „I reflowed the solder (adding more as necessary)“.

Fourth. Before you reconnect the connectors to control unit, you can clean printed circuit contact fields with soft school eraser for better contact. Eraser movement in direction perpendicular to edge only!

Again, many many thanks to Bulgaria´s research.

Viva la bulgaria. AEG 40850 working again !!! Thank you very much. I went directly to the relay, because my dishwasher didn't dry the dishes as well and voila, some 500+ EUR is saved for the moment. Thanx a lot bulgaria.

Just wanted to say a big thank you to Bulgaria. I had the very same heating problem with my AEG dishwasher and had replaced the heating element with no effect. I then followed Bulgaria's advise and bingo! the thing now works! I would make a small suggestion though. My soldering skill was very limited and it sems to be critical that the soldered area is kept neat and you should ensure that you don't use to much to repair the connection
Once again Bulgaria-many many thanks.

Check the relay located on the pcb situated inside the door of the dishwasher, this may be defective or have adry joint on the underside of the board. also check the water heater itself, this is a tubular flow through heater

This fixed my problem also. Although there were no black burn marks on the plastichousing there ewas a wire poking through the PCB with no apparent solder. Soldering iron cost me £14, inc. solder. I'm amazed, as is the Mrs.

Thank you Bulgaria!

This looks to have solved the problem. Mrs thought I was crazy as I purchased a soldering iron, very easy fix. Thanks to all who posted!

I had a similar fault on my F54850 and traced it bach to solder failure on the BACK of the control panel.
Dry joint and black burn marks round it - a very obvious fault.
...should have looked there first as it was much easier than getting to the heating element on this slimline dishwasher

The solution from Bulgaria was the best!
I had the same heating problem. And yes one of the pins of the relay was completely burned...
After some soldering it did not worked. Than I directly conect two lines from relay during working of washmachine and ...

ant it start to work.

It is great thanks to all and thanks to internet.

See U in future

JoN
www.ateliersuzanne.cz


thanks for the input.

The solution from Bulgaria was the best!
I had the same heating problem. And yes one of the pins of the relay was completely burned...
After some soldering it worked like a charm again.

thanks for the input.

Eddy

Difficult to diagnose without mor detail. however, is the element visible inside the cabinet? if not the element is in the base and is a cylindrical type. these often go open circuit