I guess it's true to say that most Atwood tanks don't use an anode...but that's only because the tank IS the anode. It's all aluminum, which as a matter of fact is the most common material for anodes in home water heaters. An Atwood isn't lined with plastic, as some seem to believe. It will degrade over time by electrolysis, just as will any other metal.
Here's what Atwood's
manual has to say about cathodic protection, and it's gibberish. "Clad aluminum protects against corrosion"???? What????
Atwood wrote:
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The tank has a clad aluminum lining that protects against corrosion and does not need to be replaced on a yearly or more frequent basis like anode rods do. A more detailed explanation of cladding is found in the back of this manual.
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Gotta love that carefully parsed sentence about rods...it only says you don't have to replace the TANK as often as you'd have to replace a rod!
The further explanation one's directed to is more of the same. The tank's aluminum, folks, and electrolysis will eat it unless there's something lower-on-the-scale like magnesium present.
