Best System Draining Approach?

[Careful_Bodger]

I have been advised by my (very busy) plumber to drain down the system to attempt to clear alledged sludge. He has lent me a radiator tail to connect to a valve end. (This is apparently better than using the drain point near the boiler for this problem.)

So should I:-
1) just connect a hose & empty away - with full header tank flow?
2) run the system for a bit to loosen the sludge, to get it into suspension?
3) close all rad valves (both ends) to force water through the distribtion system, rather than the rads?
4) do any of this with boiler on or off (before draining)?
5) swap the drain point between flow & return side?
6) none or all of the above?

Thanks!

 

[oilman]

You should put some system cleaner in first, and run it for a fortnight, then drain. I don't know that it matters much how you get the water out, if you have lots of sludge you should either take each radiator off and flush it outside, or powerflush the system.