central Heating - puzzled

[steve marchant]

Introducing anti-corrosive into system. Advice has been to put it into a radiator or the supply tank. But if the former, how do i get it into the pipework from the tank to where the circulating system begins? If the latter, how can it ever reach the circulating system? Is there any certain way of doing it - i'd appreciate some help here.

[Kevin]

put it in the header then drain some water from the system down stairs not sure if you need to empty the header before putting the solution in first though