I have diagnosed the problem on my old Ferroli Popular FF77 combi as being fan failure on the flue. I have once got away with removing the flue and spraying the fan with WD40 to extend it's life, which it did by 2 years! Tonight it has finally given up. Is it an easy/recommended job for someone who is mechanically experienced to change the fan and if any members can run me through it if they have previously done so i would appreciate any help. Getting cold now!