black specs from taps in water

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Hi all, I have a standard condensing boiler fitted in 2013, BG 330+ I think.

Trouble is dirty water is coming out of taps in bathroom. Small little black flecks.
Also since this boiler was installed I've become disabled and also looking to get it changed to a combi for instant hot water what sort of cost can I expect?. Any ideas as to the black specs in water? it's very bad!

 

[Code Breaker]

Ok will do it Monday, many thanks again.