On Wed, 15 Oct 2014 07:59:20 +0100, Charlie+ wrote:

What are these tanks made of that they need sacrificial anodes (of
magnesium etc. I assume)? As far as I know over here most/all these type
of tanks and cylinders are Cu sheet and have no anodes of this type.. !
Informative post tho! C+

Not copper. That would be far too expensive. The tank is made from
steel, which is either enamel or glass coated for protection. The
problem is that the glass or enamel can crack (or micro-crack)
allowing the water to contact the steel and eventually corrode a hole
in the tank. The sacrificial anode corrodes instead of the steel
tank. It's exactly the same as the common zinc sacrificial anode used
to protect steel hulls on boats.

Note: I am not a plumber, expert on hot water tanks, or hydraulic
engineer. I just happen to have had some experience replacing my
water tank twice in 35 years and found it useful to first read the
available literature before making any more mistakes.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558