On Fri, 09 Jul 2004 11:14:29 +0100, "Dave Plowman (News)"
wrote:



If the top mounted one has only a short element, it will only heat some of
the tank. Strange, given that water tends to circulate, but nevertheless
true.

That was the idea of the two - the lower one to heat the whole tank, the
top one just for when you only needed a small amount of hot water.

There are/were also twin length top mounting types to do the same thing.

It might be possible to remove the top one and replace it with a full
length type - they're cheap enough.

The only problem here is that where two immersion bosses are
fitted, they are - ime - always mounted in the side of the tank. So
even if the tank were large enough to fit a longer element into in the
horizontal plane, it would make no difference to the volume of water
heated...

--
Regards,

Will.