Water cylinder anodes

[Mark]

I just gave my unvented cylinder (Redring LWC series) a good look over recently (want to make sure there's nowt wrong with it before its annual service, just in case I find a cowboy).

Thinking it might be a good idea, I drained it, only to be rather amazed by the sludge that came out. About 10 litres of water that looked like pea-soup, after which I got reasonably clear water. Wondering where this stuff was coming from, I paid particular heed to the large label stating that the cylinder was fitted with a sacrificial anode.

I can't believe the sludge is coming from the water - the water here in Sheffield is extremely soft, and not even my kettle seems to have developed any real scale. Presumably then, the sludge is coming from the anode.

How long are these anodes supposed to last? There is no obvious access to the anode, and the installation and maintenance instructions make no reference to the anode, other than that it is there. Presumably the anode is attached to the actual cylinder - but that is buried beneath foam insulation, which is covered by a riveted casing.

I dread to ask a 'certified installer' how much an anode replacement would cost, especially if it's going to involve drilling out the rivets, and removing the insulation to get to it.

Or do I just have to accept that this type of cylinder is designed with obsolescence and limited life span in mind - and should be replaced after about 10 years?

Mark

[Aidan]

They should be inspected when the cylinder is serviced and replaced as necessary The manufacturers usually recommend annual servicing. They're sacrificial; whilst the anode is corroding your cylinder doesn't. When the anode is gone, problems start.

There must be a means of replacing them; are you sure there isn't a screw-in rod type thing? I don't know that make. Anodes in steel water tanks are usually a magnesium alloy ingot, connected to the tank with a bit of copper cable and lobbed into the water; something similar would work.

I think the sacrificial anodes are now prohibited by the water regulations; cylinders I've seen recently have an electric corrosion protection device that is connected to the mains.

[Andrew Mawson]

beneath

They're

Three used cylinders I recently employed in a heat recovery system all have an anode (or at least the remains of one) apparently rivetted to the centre of the domed base, and as such are totally inaccessable for replacement.

AWEM

[Aidan]

On Nov 29, 8:22 am, "Andrew Mawson" Three used cylinders I recently employed in a heat recovery system all

Strange. I suppose it ensures regular orders for replacements.