Bosch WDU28560GB/02 Washer Dryer Shows Error Code 12-00
Bosch Serie 6 Wash&Dry 10/6kg washer dryer WDU28560GB/02 This is kind of a deeper dive on the same 12-00 error fault detailed here: https://how-to-repair.com/blogs/frequent-questions/e-12-00-error-code-bosch-wdu28560-washer-dryer The problem: Bosch WDU28560GB/02 Washer Dryer powers up and goes through its start up diagnostic process which sounds like a series of clicking and ticking. At the end of the clicks it locks you out by hiding the stop / start button on the control panel and the program selection ring stops working. There is a brief time window during the start up diagnostic process where the program selection ring still works, so I have been able to retrieve an error code which is 12-00. Which I have learned from your site and a few other places, is due to a fault with the drying unit. Several hours of YT videos and Reddit thread reading later I opened up the machine, and then the drying unit itself, and was confronted by what I can only describe as something akin to a giant blocked plughole from hell. So I cleaned it out. Half of the unit is the fan and half of it is the heating element. Both were pretty disgusting. The heating element half also houses the klixon reset buttons on the side. The klixon buttons don’t seem to make any difference - there is no reset ‘click’, audible or physical. I reassembled it, plugged it in and low and behold it went through it’s start up diagnostic and it appeared that the deep clean had fixed it! I immediately began a drum clean cycle and then I realised I hadn’t reattached the ground cable. I quickly switched off and unplugged the power and reattached the ground wire, and tried again but the fault was back. I detached / reattached the ground a couple of times to double check and I deduce the fault is definitely something causing a grounding error. Which leads me to think it is either the klixon buttons or the heating element? Is that a reasonable assumption? Have you any guidance on my next step and how to approach it? Should I test the heating element? Test the klixon buttons? I am unclear how to test them? I don’t have a PAT testing machine but I do have a multimeter. If you do decide to give me a call please leave a msg if I don't pick up or txt in advance, as my ringer is off most of the time. All the best, Simon
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Hi Simon,
Thanks for your question regarding your Bosch WDU28560GB/02 washer dryer. Washer dryers can be complex machines, but understanding how their drying system operates makes troubleshooting much easier.
Here are a few essential things you should know about how your Bosch WDU28560GB/02 functions, and what might be causing your machine to fail or show an error code:
1. The Heating System & Cutout Thermostats At the top of your machine is a heater box equipped with a fan motor that blows warm air into the drum. If the heating element is faulty, it can cause an error in the main program or even trip the RCD on your fuse board.
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The Resettable Thermostat: Built into the side of the heating unit (and sometimes the wiring loom) is a safety cutout thermostat designed to automatically cut off the electricity if the machine overheats. Here is a great tip for Bosch machines: Many of these safety thermostats are resettable. If it has tripped, you can often just press the small button on the side of the thermostat to reset it and close the circuit again.
2. The Condenser & Water Valves Your washer dryer doesn't just vent hot air; it uses a condensing unit at the back of the machine. A specific, low-pressure water valve trickles a small amount of cold water down the condensing plate. When the warm, moist air from the drum hits this cold plate, the moisture condenses into water droplets, which are then pumped out of the machine.
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If this water valve is faulty (which you can test with a multimeter to ensure it isn't "open circuit"), no cold water will flow. Your clothes will get warm, but they will stay damp because the humidity has nowhere to condense. Remember to check and clean this condenser at the back!
3. Poor Airflow & Fluff Build-Up If your clothes are taking twice as long to dry, it's often due to restricted airflow. Fluff from your clothes gets drawn up into the fan motor and heater box. Over time, it sticks to the fan blades, preventing the motor from blowing air efficiently. If your machine has a dedicated "fluff cleaning" or maintenance cycle, run it regularly! It spins water up into the fan blades to clear this build-up before it dries hard.
⚠️ Crucial Tip: Watch the Video Fully! I have included a highly detailed video below, and I cannot stress enough how important it is to watch the video fully before taking your machine apart. Washer dryers contain a lot of electrical sensors and heating components tightly packed together. The video will give you a complete visual walkthrough of how the ducting works, exactly where the resettable thermostat is located, and how to safely use a multimeter to test if your water valves or heating elements have failed.
I've also added some exploded diagrams to the page to help you map out the components inside your machine.
I hope this helps you understand the issue and get your machine back in working order. Feel free to contact me anytime since I couldn't get through before! Have a great day.
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