im currently replacing a concorde wrs (255 i think)with a condensing combi the problem i have stumbled upon is that as the concorde is only for the heating i have 1 flow and 1 return at the boiler. i have removed the indirect cylinder and taken up the boards to find i have 2 flows and 2 returns.as i have not seen this before has anyone ever had the same problem? do i try to trace back and eliminate 1 of each or do i connect both flows to both returns much appreciated for your views plz.