I have a fully pumped, gravity fed CH system to which I'm planning on doing some alterations. I'm "advised" that the system ought to be power flushed after the work and before I fire it up. Is this something I can do myself or does it need specialised equipment/skills? I'm reasonably competant as a diy plumber, having made quite substantial changes in the past, including moving the boiler, so just need some advice as to what's involved so I can judge if I can do it myself. Any info, links etc appreciated. David