yeah, sorry chaps, my second question about draining and refillinmg was not linked to the job I viewed, it was just another question. I understand the systems and where pipes go etc.
But just to re-ask, if you want to drain the tank, is it better/easier to turn off stopcock/tas downstairs and open taps or drain from tank (or both) and to the 2nd part, would you go to the loft to make sure the FOV is working?
Sorry, maybe I confused things.
Also, gassafeinstall, I am not far from you in Slough area, if you ever need a free Saturday helper now and then I could be your man.