Water Heater Anode Question?

[V29]

I just changed my water heater anode before going on a trip. I know how it works, dissolves, .... is the white calcium coming out of the water in the heater or .... ? I do not recall seeing that much on it before.

FYI, I flush/rebleach my fresh water tanks every month with apx 4-6 ounces - no comments necessary on the latter. I've done that on my boats for nearly half a century keeping the tanks fresh / sanitary / clean between uses.

[Ray,IN]

That is normal degradation of the sacrificial anode. It is preventing your water heater tank from corrosion according to design Somewhere you encountered very hard water. IMO That one still has some life remaining. I realize you already know that from boating experience.
This is a better explanation: https://www.thervgeeks.com/rv-water-heater-anode/

[creativepart]

What RV do you currently have? You've posted about perhaps ordering a 2025 Vista 29V, but your profile doesn't have any into about what you have right now.

Depending on your Water Heater brand, an anode rod may not be needed at all. But without knowing what you have it's impossible to comment.

[V29]

Originally Posted by Ray,IN

That is normal degradation of the sacrificial anode. It is preventing your water heater tank from corrosion according to design Somewhere you encountered very hard water. IMO That one still has some life remaining. I realize you already know that from boating experience.
This is a better explanation: https://www.thervgeeks.com/rv-water-heater-anode/

Thanks for the link. As I said, I am familiar; I have just never seen it look like that. I probably removed them more into the life cycle and they are more used up. Just not familiar with the white lumps. Most anodes just dissolve away vs gaining a calcified look to them.

[Oldchinahand]

V29, in response to your specific question, that white crusty material is an assortment of compounds formed as the anode oxidizes. To work, an anode must be higher on the galvanic scale than the material it is protecting. i.e., typically magnesium or aluminum to protect steel, or magnesium to protect aluminum.

Those oxides precipitate into your (our) water heater and are the cause of that milky look when we drain and flush. They also flow out of our faucets, but are usually diluted to a point that they are not noticed.

Your water heater should have one, or more, check valves to prevent water heater contents from back flowing into your potable water tank. So, no worries there.

I have all the respect in the world for our fellow forum members, many of whom have provided us with sound, slap your forehead advice, and follow the RVGeeks on YouTube, but I am of a different, decidedly minority view on this subject. Similar to Galileo! This knuckle-dragging old Main Space Engineer would offer clarification by way of the American Galvanizers Association https://galvanizeit.com and their galvanic reactivity chart.

We have an OEM aluminum clad Atwood WH. We have always maintained it with a magnesium anode. 16 years on, camera inspection shows it is still sound. (Although we did replace both check valves.) We followed the same regimen on both our Catalina sloops.

Fair Winds and Following Seas

[V29]

Originally Posted by Oldchinahand

V29, in response to your specific question, that white crusty material is an assortment of compounds formed as the anode oxidizes. To work, an anode must be higher on the galvanic scale than the material it is protecting. i.e., typically magnesium or aluminum to protect steel, or magnesium to protect aluminum.

Those oxides precipitate into your (our) water heater and are the cause of that milky look when we drain and flush. They also flow out of our faucets, but are usually diluted to a point that they are not noticed.

Your water heater should have one, or more, check valves to prevent water heater contents from back flowing into your potable water tank. So, no worries there.

I have all the respect in the world for our fellow forum members, many of whom have provided us with sound, slap your forehead advice, and follow the RVGeeks on YouTube, but I am of a different, decidedly minority view on this subject. Similar to Galileo! This knuckle-dragging old Main Space Engineer would offer clarification by way of the American Galvanizers Association https://galvanizeit.com and their galvanic reactivity chart.

We have an OEM aluminum clad Atwood WH. We have always maintained it with a magnesium anode. 16 years on, camera inspection shows it is still sound. (Although we did replace both check valves.) We followed the same regimen on both our Catalina sloops.

Fair Winds and Following Seas

As I have mentioned a few times (already), I am extremely knowledgeable re galvanic corrosion and "invented" and told other manufacturers how to improve their zinc life by correctly isolating the connection point enabling the entire anode to wear evenly. If you look at the images I'm providing (Marine Environment), you will not see any "white", just slow erosion of the anode.

I have not invested the time necessary to determine of it is the difference between using Magnesium or Aluminum vs Zinc that cause the white "condensation". No big deal as long as it is normal operation. Thanks all; case Closed.

[The Raptor]

Is the Water heater Anode commonly for when Using AC Voltage or AC & LPG Usage ?

[V29]

Originally Posted by The Raptor

Is the Water heater Anode commonly for when Using AC Voltage or AC & LPG Usage ?

Just like your home, boat, RV, Trailer, .... whether you use it or not, any time water is in contact with metal, electrolysis occurs. By having (anode) a less noble metal there, it gets attacked first vs the heater's metal.

[The Raptor]

Originally Posted by V29

Just like your home, boat, RV, Trailer, .... whether you use it or not, any time water is in contact with metal, electrolysis occurs. By having (anode) a less noble metal there, it gets attacked first vs the heater's metal.

Even though Copper Water hearers are a Rarity.

I wonder if Copper Tank would be effected ?

But then I suppose you have the Heating element to consider.

[V29]

Originally Posted by The Raptor

Even though Copper Water hearers are a Rarity.

I wonder if Copper Tank would be effected ? ONLY if it could hear it - lol.

But then I suppose you have the Heating element to consider.

When two metals are submerged in an electrolyte, while also electrically connected by some external conductor, the less noble (base) will experience galvanic corrosion

The table on the left side is the Galvanic series. You can see Graphite which is essentially carbon and a nonmetal at the top. Next comes platinum, then Ni-Cr-Mo alloy, and below this is titanium. SS 316 is much below in the Galvanic series. In any bimetal contact between SS 316 and Ti, since Ti is nobler than SS 316, SS 316 would get corroded.

Zinc is at the bottom. Zinc is the least noble metal. The less noble metal is the one with a lower (that is, more negative) electrode potential than the nobler one, and will function as the anode and will corrode.

[The Raptor]

Originally Posted by V29

When two metals are submerged in an electrolyte, while also electrically connected by some external conductor, the less noble (base) will experience galvanic corrosion

You can see Graphite which is essentially carbon and a non-metal at the top.

A great document Thanks !

That was a Great Video on How to Clean the Water Tank, that will be one of my next Maintenance Jobs.

I actually have a customer that works on Submarines, we were talking about Energy Storage (Batteries), he was telling me about Graphite that Welds/Fuses to Copper I recall in some Electronic situations, as the Sub is submerged in Salt Water, it acts like a floating Battery ...or words to that effect.