Can anyone tell me the best way to clean a combi central heating system?
I have loads of blackish bits in the pipes and radiators.
I have drained down and refilled several times, but it is always there.
I often have to remove my secondary heater exchange on the combi to flush these little buggers out or the water temp will flucuate dramatically. For a few weeks after doing this the water is piping hot.
I am assuming that my system needs a really good flush / clean, but how to do it?
Steve..