Why is my water heater anode NOT wearing out??

A little bit of web searching reveals that aluminum is a better choice for freshwater applications and zinc works better for salt water (marine use). Apparently in fresh water, a zinc anode can form a layer that will negate (no pun intended) the sacrificial effects.
Someone please correct me if I'm wrong but wouldn't it make sense the more pure the water the less corrosive effects anyway?? I think it's the dissolved mineral content (soluble salts) in the water that makes it act like an electrolyte creating a small voltage pressure. It's the small voltage pressure that cause the corrosion.

That's another thing -- all of the instructions say to put it in with 8 foot pounds of torque. My torque wrench doesn't even click at that setting, so I had to guess on how tight -- I wonder if there is another way to measure torque, without having to rely on an imprecise torque wrench? Maybe you put an 8 pound weight on the end of a one foot bar, or something.

I should add that on my old trailer I used TPE paste, and that anode rod certainly did degrade every year. So I don't think the paste would be causing a loss of conductivity. And whenever I use teflon tape on an ordinary plumbing project and then have to disassemble what I have just done (you'd be amazed at how often that happens!), it is very clear that the tape has been cut by the pipe threads and that there is metal to metal contact.

RinconVTR wrote:
Teflon tape or paste...no difference. You can still be insulated from metal to metal contact using either material.

The only thing I agree with, is checking for continuity once installed. That's a great idea and all too easy.

Unless you put it in finger tight, you will have metal contact. No way to tighten it with out metal contact.

Rincon, I think you solved the mystery! That website (published by a water softener company) concludes:

“Soft water that does not contain enough mineral content to be conductive will not allow the proper electrical reaction between the anode and the steel tank (cathode). If there is little or no electrical reaction between the anode and steel tank, then the tank will not be protected. If the tank is not protected, it will rust sooner than designed.”

And since we always fill with mountain water (which is very soft -- it is snow-melt -- does not rinse off soap well but does not dry the skin, either) -- it could be that there is no conductivity inside my tank, so the anode is just sitting there, doing nothing, and that is why it does not corrode!

NOW what to do? I could bring hard water from home, although I do not like to tow with full tanks. I could put in a magnesium anode -- maybe that will give me better protection than the aluminum anode? Or maybe I just leave it all alone and hope for the best. I suppose I could drain the hot water tank after every trip and leave the anode out -- that is a minor hassle, plus insects could build a home inside the empty tank, coming in through the anode socket.

Not sure what to do, but the collective "we" are onto something, I think!

This business about the anode not corroding sort of reminds me of the Sherlock Holmes story about the dog that did not bark -- sometimes the absence of an expected event is itself significant. Too bad I am not Sherlock Holmes, though.

wa8yxm wrote:
You folks need to study the galvanic process. the rod is called a "Sacrificial anode", What does this mean:

If the water is of a type that tends to eat the lining of the tank for breakfast, The Anode sacrifices itself to prevent that from happening,, SOFT water is a great offender,, Or rather Softened, as most of the metals have been removed.

Heavily metal laden water.. Not so much.. Now, not all minerals are Metal, and those non-metal ones may deposit on the anode (And everything else) .

It is all confusing less you are a science major, and even then .. Well, you might wish to do a bit of extra studying.. I would if I did not have an Atwood water heater.

Do you have proof (even web links) soft water dissolves anode rods faster than hard? For 10 years I lived in a condo with electric heat, and those with soft water systems did not replace their hot water heater anode rods nearly as often as others...if ever.

All people really need to understand is an the anode rod does not protect against scale and mineral build up and such, it protects against corrosion of the tank/vessel. So the anode corrodes instead of the tank.

Edit: I find myself contradicting my first statement! Water hardness does make a difference. Here's a great explanation;

http://www.globalimageserver.com/FetchDocument.aspx?ID=9be6139a-8aa9-45b1-882b-ddfb56bfed3e

http://wqa.org/pdf/pressreleases/battelleresults.pdf

fpresto wrote:

RinconVTR wrote:
********The threads of the rod are probably covered in too much seal tape to make a metal connection with the tank.******* The rod wont do anything unless it is "grounded" with the tank. This has nothing to do with the hardness of water...nothing at all.

This is an old wives tale that has been floating around the internet for years and like many it is wrong. If you put enough tape on the threads to insulate from ground you would never be able to thread in in. As soon as it screws in the threads cut through the tape at the top of each thread. It is easy enough to check; put as much tape as you want, screw it in and check for ground with an ohmmeter.

First time I've ever heard this being a wives tale. I would suggest you look up what an anode rod does and how it protects water vessels.

Teflon tape or paste...no difference. You can still be insulated from metal to metal contact using either material.

The only thing I agree with, is checking for continuity once installed. That's a great idea and all too easy.

You folks need to study the galvanic process. the rod is called a "Sacrificial anode", What does this mean:

If the water is of a type that tends to eat the lining of the tank for breakfast, The Anode sacrifices itself to prevent that from happening,, SOFT water is a great offender,, Or rather Softened, as most of the metals have been removed.

Heavily metal laden water.. Not so much.. Now, not all minerals are Metal, and those non-metal ones may deposit on the anode (And everything else) .

It is all confusing less you are a science major, and even then .. Well, you might wish to do a bit of extra studying.. I would if I did not have an Atwood water heater.

I just purchased a couple new anode rods. Mine still had the original in it since new. According to my suburban heater manual it came with the magnesium rod.

The oem #232767 is the original magnesium. The dealer had an aluminum suburban rod #232768. It stated right on the package, to only use the aluminum rod, if you could get no longer than 6 mo, to a year out of the magnesium rod.

Since my original was used a season and a half, and is still about 50%, I bought two more magnesium rods. I have had no smell, but did get quite a bit of the white junk out when flushing.

I think they want your rod to eat away in a year or two, but no doubt the aluminum rod will last the longest.

Jerry

I drain my hot water tank and fresh water tank every time I will not be using the RV for more than 30 days. This gives me a chance to check the rod and keep a rotten egg smell out of the water in the water heater. I use a long nozzle on my air hose to blow out the tank and check for any sediment at the time. I clean the rod and reinstall in the tank. My rods usually last for 3-4 years.

Hi,

If it is not broke don't fix it.