On 07/07/2019 20:57, Chris Hogg wrote:
On Sun, 7 Jul 2019 20:25:54 +0100, Gareth's was W7 now W10 Downstairs
Computer wrote:

Someone has just asked me about the device sold to stop
your water pipes and tanks furring up, which consists of
a coil wound around the pipe that is then excited by
an oscillator.

Personally, I think the whole thing to be bollox.

Does anybody know the physics behind it?

I cannot see how orienting the calcium saly ions
in one particular direction will stop furring up
some distance away especially if there has been
turbulent flow in between.

I advised him to get a water softener fitted instead.

The general scientific opinion is that it's ********. The practical
experience of some people is that they seem to work. YPYMAYTYP
https://tinyurl.com/y4cq59c5
https://tinyurl.com/y28rl5xq

When I moved to this area, a fellow sceptic (geophysics PhD) said that,
in fact, magnets seemed to stop his kettle furring (the scale just
settled in a loose gritty layer). I tried one and it seemed to work too.
Then I moved house (but just across the road) and there it didn't seem
to work the same. YMMV.