Dishwasher water softener
David H. Bronke wrote 08/12/2023 at 16:14 • -1 pointAnyone here familiar with dishwasher repair, or water softeners?
I have a Siemens SE64E336EU dishwasher which has a built-in water softener. The controller board died, so I've replaced it with an ESP32-S2, which is working great... but I have no idea how to perform the water softener regen cycle, which means that dishes come out with a film of minerals on them.
From what I've found, it seems that there's just a couple of parts involved:
- the water inlet valve for the dishwasher
- the dishwasher's main motor
- a valve in the water softener system (I'm assuming this is the water softener regen valve?)
There's a chance I've missed another piece, but looking at the system, those are the only parts I've been able to find. There are some wires I haven't been able to successfully trace yet, but they seem to be sensing pins judging by the way they're wired up on the original controller board. (I think one of these may be a sensor of some sort to judge whether the water softener tank needs regeneration, but I'm not sure)
You can see my progress so far on the project at: https://hackaday.io/project/192232-esp32-dishwasher
Is anyone familiar with the process of water softener regeneration, specifically as implemented in dishwasher water softeners? Assuming I didn't miss any parts, all I really need is an idea of which of those parts to turn on and off and in what order. (and with what delay in between)
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So, I did manage to get it fixed; it seems like the "water softener regen valve" wires I found actually control _both_ valves: the one for switching the inlet to flow into the brine tank, and the one for draining spent brine. Just switching it on and turning the inlet valve on at the same time regenerates the water softener resin quite nicely! I've pushed the latest code to the GitLab project. (https://gitlab.com/whitelynx/esp32-dishwasher)
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Hey there! Your project sounds fascinating. While I'm not an expert in dishwasher repair or water softeners, your approach using the ESP32-S2 is quite innovative. It might be helpful to consult appliance repair guides, manufacturer manuals, or online forums specializing in DIY repairs for guidance on the water softener regeneration process. Best of luck with your project!
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I had the same problem with an AEG dishwasher. Controller was dead and made my own with a PLC running CODESYS.
Working for years and always I am trying to find some time to build it with one of our wizcube modules.
(https://wizcube.eu).
Now the water softener case. Simply I take it out of the equation. There are tablets that do not need the water softener processes. They have some kind of chemical inside to do the job. I am very satisfied working more that 7 years now with these tablets. Glasses are coming out crystal clear.
Is any way of sharing the ESP3 code? I can convert it to Raspberry Pico with the wiznet Triac output board.
Thank you
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Sure! It's linked from the project: https://gitlab.com/whitelynx/esp32-dishwasher
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sounds like the rinse agent
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We have a Bosch dishwasher and it refers to "Rinse Agent", so I suspect that it is adding a small amount of this juice in the final rinse cycle. If you think about it, dishes stay wet through the whole wash sequence up to the completion of the final rinse. That final rinse is probably the only place that the calcium content matters.
The only water softener systems I have ever seen have a tank with resin beads in it that have pores holding potassium or sodium chloride. The stuff in the pores does an exchange reaction with the calcium in hard water and pulls the calcium out of solution. Tanks for this are pretty good sized, so I don't think this is used in a dishwasher, but maybe there is another method that I don't know about. I just looked at the refill bottle of "Rinse Agent" and it has some Citric Acid and a couple of varieties of alcohol on the ingredients list, nothing suggesting a conventional water softener with a regen cycle.
There are some interesting comments in the Wikipedia article on Dishwasher Detergent about this.
I have worked on and dismantled a few household water softeners and been slightly involved in industrial water softener systems, but I am far from an expert on them. These comments are more just bouncing ideas around. Good luck!
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Thanks for the input! I already have the rinse aid being dispensed correctly during the final cycle, but once the water gets sufficiently hard, the detergent and rinse aid both become less effective, so the dishes still seem pretty dirty after the cycle. The rinse aid mostly serves to lessen surface tension in the final cycle so the water won't form drops on the surface of the dishes, and will instead run off and evaporate faster.
I already have a decent idea of how the water softener regen cycle works, but I'm just struggling to figure out how that corresponds to the actuators I've found on my dishwasher. This is one of the most in-depth descriptions of the regen cycle in a dishwasher that I've found: https://dishwashingpro.com/how-does-a-dishwasher-water-softener-work/
The problem with this article is that it seems to indicate that there should be 2 valves in addition to the tap water inlet valve. (I would say that valve A in that article would be the tap water inlet, except that it states that spent brine drains back out that valve when running the regen cycle)
Maybe I just need to take the dishwasher apart more and do some more tracing to figure out where the other valve is. I don't hold out much hope for that though, since judging by the circuitry on the old controller, all the other connections that I haven't identified seem to be inputs, not outputs.
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