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.