Worcester 28i Junior ?

hi you will defo ave to drain the sysytem if drain point on a low level radiator valve or a drain point on pipe work once drained and alterations done close drain point of and re-fill like u would if u were topping up the system pressure bleed all rads starting at the bottom and working up the house remember the pressure will need to be kept topped up as u bleed the radiators once done leave at 1bar and job done

gary
September 2008