my worcester greenstar mci has blocked condensate pipe?

I have been a away for a week and returned home to find EA error message and have read that this is likely to be caused by a blocked condensate pipe. There are 2 pipes one white plastic and one brass. I have followed through to outside and there is only the brass pipe the plastic pipe disappears. I am assuming the condensate pipe is the brass one. I poured 3 kettles of hot water and reset but nothing has happened. Everyone else seems to have plastic pipes..... does anyone know what to do if it is brass?? i would have thought it heated up quicker??