Hello all, Is it illegal under current regs to fit a new boiler to a single pipe radiator system? I understand the problems of lower efficiency and the likelihood of gunk from old system clogging up new boiler but the beneficiary of all the new efficiency is 87 years old so the cost and disruption of replacing the entire heating system seems out of proportion to the benefits! The boiler that has been condemned is an oil fired Worcester Danesmoor 15/19 with a rusty water jacket: I believe that's what the service engineer said but I am getting that info second hand. I would be very grateful for any thoughts/comments/ideas! Clarry.