i installed a water softener last year. finally gotten round to draining down my sealed, unvented system (also brand new last year) and refilled with lovely soft water, no limescale. great - or so i thought.
having done it i've now noticed that (some) softener manufacturers explicitly state that unvented pressurised systems should not be run with water from the softener.
anybody know why? i'm guessing it's to do with boiler components. should i drain down again and refill once again with hard water?
and what happens if you install an unvented system in a naturally soft water area? should one add the minerals to encourage limescale?