"Aidan" wrote in message
ups.com...


On Nov 28, 10:35 pm, Mark wrote:

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.

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.


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