Sacrificial anode

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Any advice or comment would be much appreciated.
On the descriptive sticker on an Albion indirect cylinder, which, I think, is about three or four years old, it states that " sacrificial anode fitted" Many years ago, there used to be sacrificial anodes available to slow down the rusting of cars. Is this cylinder anode fitted to protect the copper of the cylinder or, is it fitted to attract any scale and, in some way, disperse it through the system? If it is an anti scale device, is it loose in the cylinder and, possibly, a replaceable item, ie, through the immersion heater socket?
Thanks for any comment
 
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They tend to be fitted to bottom of cylinder sticking up and are not replacable. They rot and fall onto bottom of cylinder.

I have found that cylinders with these tend to leak on the bottom seam of the cylinder far more than cylinders without them.
 
We have 90 houses fitted with Elson tanks and these have sacrificial anodes fitted in header tank part of cylinder, and all 90 are just starting to get leaks, and always from drain off underneath which just crumbles if touched.
We are fitting a cheaper alternative at £300 as apposed to £900 for an Elson
 
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Superdupper you must have super dupper length of arm who do you change an anode attached to the bottom of a 36 inch cylinder and through at biggest an immersion hole.
 
We have 90 houses fitted with Elson tanks and these have sacrificial anodes fitted in header tank part of cylinder, and all 90 are just starting to get leaks, and always from drain off underneath which just crumbles if touched.
We are fitting a cheaper alternative at £300 as apposed to £900 for an Elson

Oh dear. And when were the sacrificial anodes last changed?
They weren't, were they?

The anode is usually aluminium or magnesium alloy. It is electrically connected (either bolted directly or connected via a length of copper cable) to the tank which becomes the cathode in a galvanic corrrosion cell.


The anode corrodes (or is sacrificed) and the cathode/tank is protected but only whilst the anode is connected to it. When the anode has corroded away, the tank is no longer protected and starts to corrode. The tank then becomes the anode is a galvanic corrosion cell in which the protected cathode is copper pipes and non-ferrous plumbing fittings.

You avoid galvanic corrosion in sealed heating systems by treating the water with corrosion inhibitors which make it alkaline and so not an electrolyte that would support corrosion. If you fail to flush out the acidic residues of active flux, and fail to add corrosion inhibitors you'll get galvanic corrosion of the radiators.

The zinc coating is the sacrificial anode on galvanized steel; the steel doesn't rust until the zinc has gone.

I believe that sacrificial anodes are no longer permitted to be used in new potable water equipment, due a changes in the Water Byelaws. Most new water cylinders have an electronic device that imposes a charge to protect the cylinder.

PS 90 anodes at about £5 each = £450.

90 Elson tanks at £900 each = whoops :oops: .
 
Most popular cylinder in UK is 36/18 have not seen any new ones with an electronic device to protect it. What make comes with this device ?
 
Most popular cylinder in UK is 36/18 have not seen any new ones with an electronic device to protect it. What make comes with this device ?

No, you wouldn't because they are copper cylinders connected to copper plumbing so you don't need any corrosion protection.

You get a galvanic corrosion cell when you have two different metals which are electrically connected and immersed in a conductive electrolyte. This is usually with some grades of stainless steel used in unvented cylinders (higher working pressure, hence the need for stainless steel) or enamel lined steel cylinders connected to copper plumbing or non-ferrous plumbing components.

I've seen electronic corrosion protection on Ariston cylinders http://www.ariston.co.uk/uploads/doc47ece67da4c3b.pdf
(Protech electronic anti-corrosion system). I'm fairly sure I've seen something similar on another make (may have been a Vaillant) but can't recall what it was.

The Ariston Classico has a sacrifcial anode, so I was probably mistaken about them being prohibited.
 
Thanks for all the interest and comments re my original question. However, I am still a little bit puzzled as to why my cylinder has a sticker saying that a sacrificial anode is fitted. The cylinder which I have is copper, connected to copper piping so, was this original fitting, perhaps, not required for all installations but,fitted, by the manufacturers, just in case there are dissimilar metals within the system?
 
The cylinder which I have is copper, connected to copper piping so, was this original fitting, perhaps, not required for all installations but,fitted, by the manufacturers, just in case there are dissimilar metals within the system?

Ring the manufacturers and ask them. IMHO, it shouldn't need one.

PS The answer I should have thought of earlier; Inspect the anode and if it has corroded, it will need to be replaced at some time. If it doesn't need a sacrificial anode, the anode won't have corroded, but it may have limescale deposits on it.

Most popular cylinder in UK is 36/18 have not seen any new ones with an electronic device to protect it. What make comes with this device ?

And on Lochinvar and Andrews gas fired water storage heaters, which both come with sacriicial anodes or 'Correx' electronic corrosion protection as an optional extra. Both are enamelled steel cylinders, I think.
 
And on Lochinvar and Andrews gas fired water storage heaters, which both come with sacriicial anodes or 'Correx' electronic corrosion protection as an optional extra. Both are enamelled steel cylinders, I think.

spot on, nasty cheap american carp.
made by white rogers.
ever see their promotional film showing how they test their gas trains? :rolleyes:
 
spot on, nasty cheap american carp.
made by white rogers.
ever see their promotional film showing how they test their gas trains? :rolleyes:

No, do tell. :D

A quick fix for hot water and an eternal maintenance problem, IMHO.
I never liked them.
 

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