UK Plumber Forum

[ITN1116]

HI. I'm looking for advice on what the black coating on the insides of a boiler Diverter Valve is. The valve was taken from an Aristion Genus 27MFFI combi and I'm planning to refurb it.

I'm aware that magnetite can exist in systems and I'm guessing that this coating may be some kind of iron oxide deposit, but although I have soaked the valve in a mild white vinegar solution (which cleans the brass nicely) it doesn't seem to clean the hard baked on deposits or internal surfaces or some of the valve components completely.

I'm no scientist but I'm sure there is a suitable acid (in the right concentration not to degrade the brass) that would fizzle away the black deposits .

I have replaced the valve, but want to keep the other one to refurb as a spare, but am also interested in the science of cleaning process.

After fitting a new valve, I also fitted a magnetite filter and dosed with inhibitor.

Any advice appreciated.

[molegrip]

Good question - i was thinking the same way and for the same reason - replacing a diverter and wanting to refurb the old one. Hope someone has the answer.

[REDSAW]

could be worth a try soaking it in system cleanser which is a acidic balance.
something like sentinel x400 for a few hours.