Bosch serie 6 washer dryer skips to drain only

I was so happy that I didn't inspect the original connector properly and just reconnected to correct port to save myself stripping whole grid of wires. It had comparing to the new connector one of the plastic guide on its frame missing. Not sure if it was filed off or some misfit from production hence I think it fitted in the wrong port on PCB.

Wow. The odds of you finding that are very remote. It's ridiculous that any connector would fit in the wrong place on a pcb. Bad design. Well done for not giving up.

So I was in contact with QER tech over the last week exchanged few short messages about the symptoms . He suggested that the PCB is not at fault in his opinion and generally was reluctant for me to send the board to test, he pointed to pressure sensor fault or possible earth leakage. I mentioned that I replaced the sensor and blown in it to try create different pressure to what he replied that this can damage the modern sensor.

I was confused whether I've blown into the replacement sensor I got yet before I installed it so I bought another new replacement which when fitted in didn't make any change to the behavior. I then decided to buy new wires to the sensor to replace the whole pressure sensor circuit for new as I though the machine stood in showcase property and what if it never worked for some silly error and because faulty it was placed there by developer.

The wire arrived today and as soon as I compared it to one on the machine the new wire connector had different guides on it which corresponded with other port on PCB which was not occupied. I tried to plug it there disconnected the original and VOILA !

PROBLEM FIXED!!

The sensor was plugged in wrong port on PCB hence it was not picking up the feed from the sensor and kept switching the flood protection on.

I have done a wash and dry today and works perfectly.

It would have been clear immediately if there was a wiring diagram available, as such I must say it got repaired by luck.

I have no clue why the connector would have been placed in wrong port, if it was repaired for other fault and then wrongly assembled and written off, no idea.

I wanted to thank you Andy, for your kind advice and guidance through the course of testing. I have never had washing machine opened before and with your help I was able to begin understand how such machine works in principal. THANK YOU!!!

Great to know it won’t hurt the pump running dry, coffee machine brass pumps don’t like that at all.

I contacted QER this morning, tech who repairs these PCB’s is back at work on Monday so will get to know more then.

Happy weekend.

Contact them first to make sure they can help. The pump running dry won't hurt.

When the machine is plugged into mains it performs some check, interesting fact is that the door lock remains locked at all time.

When the selection is left on OFF it doesn't go into draining, only when the program selection is made and program either started or not.

To be honest I have left the machine draining until it stops itself only couple of times when I acquired it as I'm not sure if it is safe for the pump to be running dry. So I have to try that again to see if it produces any error itself. From what I understood from the manual it only shows the type of error which can be rectified by consumer.

I think I will try to send the PCB for a test to QER next week as you suggest, I haven't found this type of PCB in their order search though so I hope they will be able to test it.

If it tests using 500v DC that would work. But it's still a lot of money to spend just to test a washing machine. It's not even certain it will find anything. It might not be that much more to get a proper engineer in, and they should tell you exactly what's wrong and even may fix it if it isn't anything too serious.

The pump shouldn't have any power, have you tried safely disconnecting the live wire on the pump to see what happens? It's probably a waste of time but it might do something different.

Maybe the PCB does some self checks when switched on and is finding something. However, it should abort and give an error code after detecting a fault. If it thought it was overfilling it might operate the pump but it would operate it for much longer as it is trying to get rid of a lot of water. If it thought it was overheating it would operate the pump too. But for longer, and machines I've seen reacting to overheating usually combine that with letting water in to cool everything down.

So the fact that it misbehaves before even any wash cycle is selected or attempted implies it's failing a self check, or there's a fault on the pcb. If determined not to give up you could at least eliminate the pcb by sending it to QER repairs for testing and possible repair. But apart from I'd like to know what it turns out to be it remains a big gamble with your time and money.

When program is selected but not started it will begin to drain for few minutes and will stop not producing any error code. It only produces an error code when selection for an error reading is dialed.

As I get it it detects a fault after 2 seconds and starts pumping the empty tub out regardless whether a various program is selected and started of or not.

I have thought that one of the relay on PCB could be fried but then I'm confused that it would have those 2 -3 seconds delay to react and send it to drain and abort.

As you say it might be some insulation or earth faults, which I'm not able to measure. I have to say that all of the earth connectors were pretty loose with not much of a grip which I have made a bit better.

I saw some diy insulation test meters around £50 mark , do you think that would do the job to measure?

Thanks for the clarification Jan. It's just that once a programme has started you are not allowed normally to press any more buttons so it is normal for them to start beeping and do nothing once you have started the programme. It is very strange that the machine starts draining when you have not pressed the start button. If when it starts draining before you have pressed the start button what happens if you leave it? Is that when it produces an error? Unfortunately it doesn't look like a straightforward simple thing you can repair. Things like insulation or earth faults can cause weird behaviour in a washing machine. But you can't check for an insulation fault without a specialist insulation test meter.

I showed different situations in those short vids.

If I select a program and touch nothing then after 2-3 seconds machine starts draining and touch display becomes unresponsive ( that's the case of the video I'm pressing all buttons and only getting double beep )

Basically if I select the program and then press Start button immediately when time appears on display the program starts but only for 2 seconds and then it skips to safety mode draining the water.

It starts draining after 2-3 seconds from program selection is made regardless whether I press Start or not.

There are videos showing those first 2-3 seconds of different programs ( Cotton, Intense Dry, Drum Clean) .

In left lower corner of the display is STATUS led coming on for those 2 seconds and then coming off as the program is aborted.

Hello there. I'm not understanding why you keep pressing the start stop, pause button and all the other buttons? What happens when you put it on a non-fast coloureds cottons wash, then switch it on and leave it? Washing machine should normally engage the pump and then after up to 30 seconds it should start taking in some water. But the videos you have put up are puzzling to me because you just keep pressing lots of buttons and getting beeps?

Here is the video of error code reading

https://www.youtube.com/watch?v=_O_ana9pxAY

https://www.youtube.com/watch?v=4FXyDoYlq_0

https://www.youtube.com/watch?v=emvXHrncefA

https://www.youtube.com/watch?v=A2NsN0e9qBY

https://www.youtube.com/watch?v=DFvjI8FOdo0

Managed to post the links to the videos. I will take a video of the error code and post later.

I was away few days so haven't done anything on the machine since last week. If I recap the situation :

- error code E26 , analog pressure sensor faulty ( now replaced)

- there are 3 wires to the pressure sensor and the pressure tube,

- I have physically checked for tube blockage

- I will check the continuity and for possible short circuit of the wires, I think I have already done that before but to be 100% sure I'll do it again

If the wires are fine I understand that the problem would be on PCB , what do you think Andy?

Any time a fault is fixed, the error should reset. It may be retained in a memory accessible via special methods but it should stop being displayed to a customer. Try just linking to the videos?

Hi Andy,

this morning I came across you tube video on how to read an error code and I tried it and it worked. I got E26 error code on the display which corresponds with faulty pressure sensor. Now I don't know if I need to clear that error somehow or if the problem persists and I should rather concentrate on measuring continuity of wires and maybe track a path on PCB. I'm going away for a week tomorrow so I won't be able to do more tests until back.

I have also posted few short videos on you tube of the behavior of front panel display and starting the programs works right now. If you interested to see it I have attached the links:

Ups, can't post with you tube link.

Thanks for the update. I would have been surprised but pleased for you if it had worked. If you still suspect the PCB you could still try contacting QER. Have you tried checking parts individually with continuity test meter as some parts can cause weird faults if they are open circuit. Thinking of the heating element, motor etc. Any faults are supposed to be captured by the software and produce an error code. So faults that don't produce an error code are often very difficult to diagnose.

Sadly, have to report that the fault persists after replacing the sensor, so as time will permit I will be trying to crack it. Will do basic checks of wire continuity around the sensor and door lock and if nothing will probably send the PCB for a test. Damn

I am wondering if maybe the difference in resistance readings or voltage readings in the coil are likely to be so small, with such a small magnet, and such relatively small movements that it is only readable accurately by the PCB itself.

If it proves to be it I will dissect the faulty sensor to see what it looks like inside. I got the sense like if it was seized in its upper part (higher pressure). For now I'm sticking with the fact that it does send constant reading to the PCB ( when i created different pressure conditions by blowing in tube) and now when discovered that the front panel communicates the symptoms encouraged me to replace it and see. I mentioned on my first entry that the machine is 2-3 years old but only done 2-3 washes so it is like brand new and clean quite pleasure to work on. I believe the motor on this machine is brush-less, having some magnets instead.

Until tomorrow when I will replace the sensor I'd like to think that it will be sorted then will push further with it if not.

Just a few extra thoughts just in case they are helpful. According to the error information I have on Bosch washing machines (which is far from up-to-date) there should allow about 6 minutes to drain, and also about 6 minutes to fill. So if there is an error where the washing machine doesn't detect it has taken the correct amount of water in, or doesn't detect that it has pumped the waterway successfully it should have tried to do so for around 6 minutes before aborting. Also most faults should produce some sort of an error code.

There should normally also attempt to start the motor 8 times before advancing to the off position. Have you checked the carbon brushes just in case? Most faults should occur after several minutes the absolute minimum. So if the washing machine thinks it is full of water and you put it on a spin cycle it should try to pump the water out for about 6 minutes before aborting.

Fingers crossed. It is difficult to imagine what might go wrong with a modern pressure switch. The pressure switch has always been one of the most reliable parts in a washing machine. However, they are now a very different design to what they have historically been for probably over 50 years. As far as I'm aware they have a magnet that presumably gets raised up and down by air pressure inside the coil. An extremely simple device. The only thing that I would expect to go wrong with one is if by any chance the coil goes open circuit. I can't imagine anything going wrong with the magnet. Of course other issues such as a blocked pressure system, or an air leak can cause problems with the pressure switch function. If you still have problems by the chance make sure you check the continuity of connections from all of the pressure switch wires right back to where they connect to other parts in the machine if you haven't already.

I will, definitely. I should have the part on Tuesday.

Let me know what happens whether it fixes it or not.

Hi Andy,

this is the machine with the latest analogue pressure sensor with the magnet inside the coil.

The machine does its check when plugged in mains (electricity) and when selection of a program is made and I think sets itself to a safety mode upon receiving this incorrect feedback. It also never release the latch on the lock so the door remain locked at all times.

The discovery is that I think that there are 2 seconds delay before the PCB locks the display front panel after the program selection is made and if I press START the program immediately after it is made available on the display the program then starts and runs for 2-3 seconds and is aborted with the drain pump coming on (the display and controls then become locked) keeping draining for 3-4 minutes and then stops as I think is programmed for safety mode so that with the valves shut the drum should be emptied in that time. It is very much possible that the programs begin with short draining.

I think that the voltage return from the pressure switch should fluctuate between 5 - 10 V and I'm reading constant 9.4 V, it sort of explains the symptoms for me at this moment.

The sensor is £40 from Bosch , but I found exactly the same at ApplianceSparesWarehouse for £18 so I will give it a go to replace it and see if it would fix the error.

Many thanks again for your thoughts and information on the subject as it directs me towards understanding the logic of the machine's behavior.

Pressure switch should normally be off or on. Historically they’ve just been off until the correct amount of water creates enough pressure to switch the pressure switch on. The latest type of pressure switch seems to have a magnet inside a coil so potentially they might detect proper levels.

If a pressure system is telling a washing machine it has water in when it hasn’t it usually tries to wash and rinse with no water in the drum. But modern washing machines operate the pump for 30 seconds before filling to wash. So it’s possible they check to make sure there’s no water in before filling. But I would still expect it to try draining the water out for a few minutes before giving up.

If the pressure system is saying it has water in when it hasn’t I would still expect it to work on a spin only cycle. I’d expect it to try to drain water out for 2 or 3 minutes waiting for the signal that the water has gone. When it doesn’t get the signal it should then abort without spinning.

If the washer thinks it’s overfilled though it should keep pumping trying to get rid of the water. But again I would expect it to try for several minutes at least. If the pressure switch isn’t expensive it might be worth a try but not sure. Fingers crossed.

I was able to work on the machine again last night and I think I have a breakthrough discovery on the problem.

By coincidence I figured out that I'm able to start the selected program. I can start the program in first 2 seconds when it lights up on the display, after 2 seconds the machine aborts the program and begins its safety mode of draining water. When I select the drying program then in those 2 seconds I get about 1 revolution of the drum and a program status light comes on until aborted. There is less to observe when washing program selected as those begin with water being filled, but again in the 2 seconds span I have program status light coming up. When a rinse program selected I get correct rinse status light on. Also in those 2 seconds I'm able to make adjustments to the program (temperature, spin rpm, delayed start..) . Door lock is constantly closed. This led me to think that the PCB might not be at fault.

I have measured the returns from the pressure sensor on the ports at PCB whilst blowing in the pressure tube and I get constant readings at all 3 ports regardless the pressure created. I sense that when I blow in there is very little travel enabled as opposed when I suck the air away the magnet (or what is inside that coil) moves lot more.

For this day I'm drawing a conclusion that the pressure sensor is at fault being stuck and sending incorrect constant information that the machine is filled with water.

I will order a new pressure sensor on Monday and will see if that will clear the fault.

Understood about the neutral return, thank you. I will check your site, I very much appreciate your help.

The heater should come in when correct level of water is inside. It’s possible for some parts to have a live supply but if there’s no neutral return it won’t operate. Some machines in the past have had all components switched on and off on the neutral side, with all parts in machine live all the time.

It’s possible it shouldn’t be live though.

Check out my site Whitegoodshelp and search for how pressure system works for an idea about pressure system.

Hi Andy,

thank you for for your further thoughts and suggestions.

I did blown the tube the other way into the tub as well and was fine, no resistance at all and I could hear the 'sound' of my breath entering the tub. I have also tried to start a program with the tube from pressure switch disconnected which has not made any difference to the behavior I described above.

As time will permits (busy week ahead) I will check the machine is earthed well and will also try to get more readings from the components. Shall I ask you if the heating element should start heating as soon as the wash program is started or only after the water in the drum is filled to satisfactory level? I need to return to this and do more measuring but I think I had a live on heating element whilst the draining pump was active but didn't sense any heat in the drum.

This all IS so confusing, I will begin a thorough analysis of each section of the machine so hopefully to be able to get more clues.

Thank you again.

Jan

Did you blow down the pressure pipe the other way? Into the tub? A blockage at the other end can cause problems for sure. It can cause the washing machine to overfill. If a washing machine thinks it is overfilling, it will commonly energise the pump constantly trying to get rid of the excess water. It will keep the pump running until it receives the signal that the water has been pumped away. However, a fault in the pressure system, or a blockage in the pressure system can prevent that signal from ever occurring.

Having said that, if there was a blocked pressure system then as soon as you remove the pressure tubing from the pressure switch the air pressure would be released and the pressure switch should switch off. This should stop the problems, at least until more water got into the washing in and caused the problem again.

Another fault that can trigger the pump to be running constantly on some washing machines is believe it or not earth faults. If there is an earth fault on some washing machines they can behave bizarrely. So make sure that the washing machine is properly earthed. But more importantly you would really need to check that no parts on the washing machine have low insulation readings. This would require using a specialist meter though that tests with 500 V DC.

Also it is common for faulty PCBs to show no visible problems. They can of course have dry joints, or blown parts, but many component failures will not have visible signs. So the lack of any signs doesn't prove anything when it comes to diagnosis.

I have had the pressure sensor out and did some measuring whilst blowing into the pressure pipe and I'm getting constant voltage on all 3 ports of the sensor. No voltage fluctuation whatsoever. Does this suggest that the sensor could be faulty?

Another observation is that the machine starts draining even with the door open. It signals the door is open but however begins to drain. Could this suggest anything in the loop? Perhaps the pressure sensor?

Hello Andy, thank you for giving a thought to my issues with the washer and your advice on pcb. I had the pcb out for visual check and didn't notice anything wrong on the board, the control front panel board is also without any noticeable damage.I pulled and reconnected all connectors in case of some oxidation build up. I will yet make a visual check of the motor module and will run tests on all sensors, solenoids, pressure switch, etc. before deciding to send the pcb for test. The machine stood in showcase property for 2 years and apparently stopped working after few washes when someone moved in. Do you think that the solenoids could seize or something if they not acted for so long being plumbed in ? They are closed not opening, but as I said i must yet check if they get the impulse to open. Many thanks.