SACRIFICIAL ANODE, other than the hot water heater ?

[mountainborn]

Most RVer's know about making periodical checks of the Hot Water heater's sacrificial anode. Yet, I have talked with some that have additional anode's that they have little familiarity with. Here is the link to the story with photo's and locations.
Blog | Oliver Travel Trailer

[AWCHIEF]

As far as I know some older Airstreams only have the one hot water anode. My hot water heater is less than a year old and does not have an anode. Apparently materials and methods of construction have changed. My boat on the other hand has 7 anodes that that usually have to be replaced at least once a year.

[A W Warn]

I've owned several Airstream trailers, models from the early 1970's to 2000. None of mine had anodes. I helped a friend repair his water heater recently, that had the exact same Atwood water heater with a anode rod in the drain plug hole, in a Minnie-Winnie. I was wondering why his had one and mine did not?

[idroba]

Airstreams use water heaters with aluminum tanks and the manufacturer says specifically that sacrificial anodes are not to be used. However, even though not needed and stated so by the manufacture, there are after market anodes available in the length which will fit in them. So, you can find them in use. Although I do not know the chemistry involved, I believe I read somewhere that an anode, used with an aluminum tank, will accelerate the corrosion of the tank.

Some other brands of water heaters use steel tanks or glass lined steel tanks and they require an anode and replacement when it is worn out. So, steel tank uses anode, aluminum tanks do not.

[Protagonist]

Originally Posted by A W Warn

I've owned several Airstream trailers, models from the early 1970's to 2000. None of mine had anodes. I helped a friend repair his water heater recently, that had the exact same Atwood water heater with a anode rod in the drain plug hole, in a Minnie-Winnie. I was wondering why his had one and mine did not?

His didn't need one, either. It probably didn't come from the dealer with one.

Atwood water heaters don't need an anode because the tanks are lined with aluminum.

Zinc is very close to aluminum on the galvanic table, and so it doesn't work very well as an anode for aluminum. If you really want to install cathodic protection for an aluminum water heater tank, the anode should be made of magnesium instead. You can tell your friend with the zinc anode that next time he pulls his drain plug, he should get rid of the anode because it isn't doing him a bit of good.

[m.hony]

My previous sob trailer had an anode rod in the water heater. The Airstream does not. I can't think of any other component that would need one.

[A W Warn]

Originally Posted by Protagonist

His didn't need one, either. It probably didn't come from the dealer with one.

Atwood water heaters don't need an anode because the tanks are lined with aluminum.

Zinc is very close to aluminum on the galvanic table, and so it doesn't work very well as an anode for aluminum. If you really want to install cathodic protection for an aluminum water heater tank, the anode should be made of magnesium instead. You can tell your friend with the zinc anode that next time he pulls his drain plug, he should get rid of the anode because it isn't doing him a bit of good.

I was helping my friend flush the water heater and water lines since he was having a low flow issue. The anode rod was about 50% dissolved. Obviously the corroded rod debris was inside the tank. I was really surprised at what came out! There were larger particles than what I normally see when I flush my tank. After flushing, the flow was back to normal. I told him I did not think it was necessary to install a new anode and the old one contributed to the problem he was having. He bought a new one and installed it anyway.

[lewster]

Suburban water heaters (you don't heat hot water!!!!) is the only water heater that requires an anode. Using an anode in an Atwood water heater can void the warranty, as the manual specifically states that no anode is necessary or required.