My Siemens dishwasher (model SX66M084EU/50) started showing error E31 suddently. This error indicates:
There is a fault in the dishwasher’s drying system. The water does not heat up during operation. The dishwasher does not dry. Please contact Customer Service, quoting the Siemens dishwasher error code, as this fault can only be remedied by Customer Service.
Technically there’s a moisture sensor in the heating element and once it detects water, it prevents heating up and ultimately leads to error E31. Apart from the mere display of the error code the dishwasher still kind of worked, but washing would be done with cold water, and dishes remained wet since the drying up did not work.
Of course, my first step was not to contact customer service but looking around the internet what I could find. The dishwasher is 13 years old and comes with a new (at the time of purchase) Zeolith heating system. The repair shops all have videos that show how to self-repair some usual errors and for E31 on a Zeolith dishwasher they proposed to take a hair dryer and vent in fresh air into the heating system (you can open it at the back of the inner dishwasher). So I did that for 20 minutes but it didn’t help.
Removed from housing
The Zeolith system consists of a box and heater sprials inserted into that at the bottom of the dishwasher; despite the position below the cleaning room, no water may get into it to avoid damage.
Unmounting the lower bowl below the dishwasher
Zeolith box - you can already see some dirt coming out
Heating spiral w/ lots of dirt and wet
After removing the bottom bowl of the dishwasher and completely dismantling it, I could remove the box and heater from below. The metal box had a small hole, and there was a rusty fluid below, showing that water had been coming in there for years, supposedly. I removed wet rust from inside the box, cleaned and dried the heating spirals. After another waiting period (a day or so), the error had disappeared and washing the dishes would again get hot water to do the work.
Replacing the Zeolith parts would also be possible; however, since the mineral box and the heater replace parts sum up to ~300€, it is not really on the cheap side of repairs - a new budget dishwasher accounts for ~500€.
Conclusion
I have often times already repaired defects on that dishwasher. What I like about these washers is that they’re pretty good to repair. There are replacement parts available and also DIY videos that you can follow. This time, though, I actually had though I’d have lost the fight, since the heating seemed to be in such a bad condition.
Even though there’s a small hole in the Zeolith containment, there is no water supposed to go there, so it shouldn’t be a problem.
Took a weekend, saved 500 bucks.
PS: The new dishwashers from the local electronics stores all somehow seem to be cheap plastic models.
