Thanks for all your advice!
Think I will change it - the 1700 I have so far comes with a flush and a filter...
I am guessing this is not a power flush - although I will change all the rads at the same time as to be honest that's not too expensive, they're old and inefficient, and it saves me...
My first post here - I hope this is the right forum for advice on what can be done for this!
I had my boiler inspected today after intermittent problems with hot water.
Turns out the sludge in my grotty old heating system has blocked the main heat exchanger in the boiler - I acquired the flat...