Anode Rod in a Atwood Water Heater

[Theberrys]

The word on the street is you don't need an Anode Rod in a Attwood Water heater. Here is a picture of one I just removed from my Attwood six gallon heater after a year.
I think I'll buy another one...... I'm just saying!!!

Dick

[wa8yxm]

As I recall at one time Attwood DID make a heater that used an anode rod.

However the current models do not.. they come with a nylon plug instead.

[Theberrys]

Well after a bit more study I find.... I brushed off the rod to find the white stuff is the rod material as designed.
Anode rods are effective on ferrous metals.... http://en.wikipedia.org/wiki/Galvanic_anode and Aluminum is non-ferrous. So although it appears the rod had collected minerals, the minerals on the rod are the rod it's self.
It's possible a Anode Rod in an Aluminum tank adds to the problem and not only is unnecessary but may contribute minerals to the tank.

[RickO]

As a newbie, I bought a new 40 DP. The dealer made a big mistake and told me I had to replace the nylon plug with an anode plug. A year later when I went to replace it I found it to be completely eroded... leaving a huge mess in the bottom of my tank. The threads of my drain opening were damaged to the point where I can now not even get a nylon plug to go in so I'm continuing to use the metal drain plug with several wraps of Teflon tape.

Rick

[Dave78Chief]

Atwoods position on the topic:

WATER HEATER TANK CORROSION
Pinhole leaks from galvanic corrosion may cause the water heater tank to fail. Microscopic particles of metals (like iron and copper) suspended in water, set up a reaction inside the water heater that is not unlike the principle on which an automotive battery operates. The aluminum tank is the anode and the metals in the water serve as the cathode. Consequently, the aluminum gradually sacrifices itself and aluminum particles are carried away with the water flow.
A white scaly material (aluminum oxide) often is formed around the points where the heaviest action is taking place and heat accelerates the process. Severity of the problem varies considerably in different locales depending on the metal and mineral content of the water. White deposits inside the water heater tank are usually from water impurities that have settled out.
Periodic flushing of the water heater tank under pressure is recommended to slow down this process. For flushing instructions see your owners manual or contact Atwood for a copy of our recommended procedure.

ATWOOD CLAD TANK
The Atwood water heater tank is constructed of a core of high strength aluminum. The interior of the tank consists of a 15% thickness of type 7072 aluminum (pure aluminum and zinc) that is fused to the core during the rolling process.
This material protects the tank from the affects of heavy metals and salts found in waters throughout the country. It is anodic to these heavy metals and acts much like an anode in a steel glass lined tank except it will last much longer. There is also no need to replace an anode on a yearly basis. Flushing the tank on a regular basis has been found to be helpful in insuring the best performance of your water hater and adding to the useful life of the tank. For flushing instructions see your owners manual or contact Atwood for a copy of our recommended procedures.

Dave