07 February, 2015

Replace magnesium sacrifice anode in hot water tank by yourself

After four years working properly, it is time to do the maintenance of DHW storage tank from the solar thermal collector  changing the magnesium anode which prevents the deposition of oxide by galvanic protection .
Sacrificial anodes will last more or less depending on tank size and the degree of degradation thereof , that is; if you have many areas without paint, he's paid to oxidation and anode (magnesium in this case) will provide more ions, degrading its structure more quickly.
First of all, we acquired a couple of sacrificial anodes, are cheap, about 15 € each (I ordered them on Ebay for a company of Madrid). To change it, release the cover ( IMPORTANT empty it first ), loosen all the lime and use mud accumulated over the years:

You can appreciate the embedded lime exchanger, the anode is the brown bar:

As seen carries a support rod threaded extra-long, which will shorten half. I scraper to clean the exchanger and improve heat transfer:

I was right to buy two anodes, since being a large deposit of 150 liters, the leading, although most had lasted five years at least, is quite large.
Both will join to form an anode-length , in this well-preserved deposit endure 15 years at least.

Magnesium is softer than aluminum and easily machined ; enrroscar one another to just use a drill for steel (HSS cobalt better withstand high temperatures so that lasts longer cut) to a little smaller than the thread cobalt.

To make the drill I 've used a screw and guesswork as straight and centered as possible.Then, using oil (3 in 1 for example) and some strength we can (if we have males to make it as it should), we can make the thread with the same screw as it is quite soft , until either the top:

Do the same with the rod-holder ; I harnessing the piece that I cut the threaded rod, prepare the thread on the lathe:

And we need only screw it into place to reattach everything in place:

With a clean hose inside the tank and remount everything to forget about maintenance for 10 years :

Bluish inside the tank;)

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