There are two valves which I used to drain the system down with - but gravity doesn't always do its job fully when draining it down by opening the valves on their own.
I thought that if I open both of the draining valves, and then opened up the tap which I use to top up the closed system with water, would that effectively flush out the whole closed system.
Am I being naiive? :-)
If not, what would you all suggest as the best method of fully draining the system?