🚀 go-pugleaf

My combination boiler managed after some years of use to scale up
completely on the hot water circuit. The water in my area is hard
enough to hammer nails in with, so this isn't at all surprising.

What was somewhat surprising was that my plumber suggested that I fit,
not a water softener (he claimed that this would impede the flow: I
believe this, I don't have a water tank at all) but a plastic cylinder
with a large magnet in it to the cold pipe. The claims he made were
that:

a) it wouldn't stop scale build up completely
b) it wouldn't exactly soften the water
c) that it would cost 50 pounds

The last one I believe; in fact I believe all the above claims, but I
had no reason to think that it is in any way worth fitting: i.e. I
had no reason to believe it makes any difference.

The box for one made no claims like: 30% less scale or anything
else... It did say that you should place it 1 meter or less away from
the protected equipment.

Question: Do these things work, if so how well, and what *physically*
is going on? (For the sake of network bandwidth- postings like: "I've
got one and its *really* *good*" are probably inappropriate, unless
you've done a decent control experiment to prove it ;-)

-Ian.