I’ve been powerflushing as you can see I got a lot of muck out of the old radiators.
Some of the radiators were not getting hot but after a day of flushing and new radiator valves the system was working like a treat.
I always recommend a powerflush before fitting a new boiler as you don’t want all that muck in you new boiler. I’m sure boiler manufacturers would weasel out of their warranty if the central water was this dirty.