Hello,

Does anyone have any advice on the best way of getting magnetite out
of the secondary heat exchanger of my combi? I've just tried to
descale it on the assumption that its erratic performance was being
caused by limescale on the secondary side. Howerver, from what I can
see it's actually the primary side that's clogged up with black
magnetite flakes.

Is it possible to chemically dissolve magnetite? Or is it a case of
chucking it out and getting a new heat exchanger?

Incidentally, I'm a bit baffled - the system does have corrosion
inhibitor in it, and when I drained off a gallon or so of water from
the draining cock to depressurise the system the water was virtually
clear. The magnetite seems to be quite selective.

Cheers!

Martin