Corrosion on 220v unit

This particular probe is at +5v above the rest of the stainless parts, and it appears to be for liquid level sense. I suspect that it has enough current (albeit still small) running through it during the cooking process, and that’s what causing the galvanic corrosion. It’s started to eat away at the metal on my unit and, I imagine, will eventually cause the unit to fail, so I plan to return it when my production unit arrives (and hoping that doesn’t have the same issue).

I just received my units this week (kickstarter).

@mdubc‌ That’s actually not corrosion. That piece is a water sensor, which picks up minerals in the water and changes color to match the minerals.

@"Stephen Svajian"‌ You should consider writing in the manual that discoloration of the sensor is normal and that it can be remedied with Bar Keeper’s Friend [and something available worldwide].

Unlike @aarthur‌’s most of the “rust” went away with vinegar on my 220v dev unit.

Alright, alright. That response makes no chemical sense whatsoever. I am a 6th year PhD student in Materials Chemistry with a focus in electrochemistry. . This is an issue of corrosion.

There are simply no mineral deposits that will have the same color as what is shown very clearly in the pictures. If you are trying to tell us that the probe itself is changing color as a result of some interaction with the water, I have to say that I have never heard of a sensor that should do this.

You also seemed to have skipped over responding to other users on here, @clarklab and @Soygen, without any significant response, and considering @clarklab mentioned that significant degradation of the probe has been observed, you probably shouldn’t just tell us to ‘wipe it off’. @aarthur has pointed out that it’s a water sensor, verified by you. Which means to me that it is verifying that the Anova’s heating coil is submerged in order to keep the device from running dry and potentially damaging itself. Regardless of what the probe is supposedly doing, it should not be rusting!

You can tell from @aarthur 's picture: https://twitter.com/Alan_1/status/532097340572565504/photo/1
And from both of my pictures (of used and unused units): Imgur: The magic of the Internet
that there seems to be a dot on the probe - a point of failure where the corrosion is localized to begin with.

Do not dismiss this - if there is someone else who can help to identify and address this failure, please refer this problem to them.

Thanks @mdubc‌ I will try and take a macro shot on the weekend which shows the pitting in the stainless steel. I think Anova are ignoring something which is going to result in significant device failures somewhere down the track.

I agree. I’d hate to see them 20,000 orders in and refuse to address something that bankrupts them.

I doubt it will bankrupt them, there’ll be some law that protects them from that eventuality. From looking at the images provided, it’s not simply some discolouration, whatever’s going on is actually eating through the probe.

That’s why you use an AC signal on a conductivity probe. Are they?

ok, here’s some close-ups. I have only cleaned this probe with a light scourer as recommended. This removed the orange discolouration, but see for yourself what’s going on underneath it.

“normal” section of probe (just for reference)

corroded section of probe

Close up 1 of corrosion

Closeup 2 of corrosion.

@"Stephen Svajian"‌, @levig‌ , @JordanHouston‌ I await your reply.

The part in question is a water sensor. The sensor picks up minerals in the water, which is why there is discoloration. We sent the images to our chemist. There’s no issue with the part.

@"Stephen Svajian"‌ so how does your chemist explain the pitting in the surface of the sensor? Those are holes in the photos, not bumps. Do a Google image search for “stainless steel pitting” and you will see the same thing.

@"Stephen Svajian"‌ Seeing those pics I’m sincerely concerned about my kickstarter order for 220 V devs to be used in Germany. You should really look into this issue. There is definitely a quality problem of the stainless steel used. I’m currently using a fusion chef and there is no such a problem. I’d rather wait until this problem is fixed instead of receiving damaged material and sending the two devices back to the US.

@uboehme‌ I don’t think the problem is with the quality of the stainless, as none of the other probes have this problem. It’s galvanic corrosion due to this probe carrying 5 volts DC, which over time causes the pitting of the stainless. As @sousevide‌ pointed out on the first page, this function should be implemented with AC or similar to avoid this type of problem.

@mdubc. I’ve noticed rusting on a metal “weight” that I used to keep the bag submerged. But not on the probe. My water is very high in calcium .
Would changing to a plastic container stop aarthur’s corrosion? What about distilled water? In your experience, what type of metal pot would be wrong to use with a stainless steel probe if indeed galvanic corrosion is at work?

@markc I’m using a plastic Cambro container. Though for the most part, the corrosion involved here should be independent of the container being used. As @aarthur has said, the probe in question is corroding because a potential is being applied to it relative to a second probe in contact with the heating element.

@aarthur Just a quick note: if the steel was of the appropriate grade, it should not corrode even at 5V DC. But you’re right, there may be a way to slow this effect by utilizing some clever electrical engineering, though. The reason the other probes aren’t corroding is simply due to the polarization of the applied potential, i.e. the direction of current.

@Stephen Svajian We clearly know that the part is a water sensor. Reiterating this is a bit frustrating. Also, the sensor ‘picking up minerals in the water’ is not the issue here. As anyone who has ever used a water kettle or a coffee pot knows, deposits from tap water, most typically limescale, are hazy and white and not reddish like we see here. And yes, limescale is a deposition and can easily be cleaned with vinegar or more aggressively with a product like barkeepers friend. Rust will also be removed by vinegar etc. but the iron will be removed as well, resulting in pitting the stainless steel probe.

Now frankly, I don’t care to give you a science lesson. I only want to convince you to take this seriously. If your ‘chemist’ says the discoloration of the probes in these images isn’t rust, but instead some non-corrosion related deposit, then I implore you to consult more people as the evidence here is significant.

Also frankly, if @aarthur or myself or any other concerned reader wanted to, we could simply post this thread or a copy of it to reddit and other social media sites. I can’t speak for everyone here, but I don’t think we are trying to cause you major troubles, but we are concerned about the longevity of the products we have purchased and do not want to be dismissed by someone who does not seem to understand the difference between limescale and rust.

Also frankly, if @aarthur or myself or any other concerned reader wanted to, we could simply post this thread or a copy of it to reddit and other social media sites. I can't speak for everyone here, but I don't think we are trying to cause you major troubles, but we are concerned about the longevity of the products we have purchased and do not want to be dismissed by someone who does not seem to understand the difference between limescale and rust.

Correct.

I had the exact same problem with my MK 1 before even using it.
This is a picture from the unpacking. It had a large ‘rust ball’ on it which isn’t visible as i scuffed it off before taking the shot, but you can clearly see the remaining corrosion.

At the time I assumed it had come from Quality Control testing, I had a few issues with the brand new IC but being UK based and having just forked out customs and tax on it I opted to live with it.

I keep an eye on the rust, and have ordered a MK2, but seeing this thread and the dismissive response from Anova has left me really questioning what kind of company I have ordered from.

My guess would be a sub-standard stainless steel combined with galvanic corrosion as pointed to by aarthur.

Good to see this thread rolling on. I forgot to take pictures but I’ll try to get that done soon (thought I doubt I’ll be able to beat those macro shots on the last page).

Hey Everyone, We don’t have an answer on this yet. I just wanted to let you all know that this is a high priority issue that we’re looking at. We’re working on this. If anyone wants to return their unit, please submit a request here: Returns – Anova Culinary.