Hi guys. First post on here. Called out to fault on Alpha HE 33. Fast blow fuse found to have blown. Faulty fan found to be problem. New fan installed and tested. Four days later and a call from customer to say boiler not working again. fast blow fuse found to have gone again. Replaced and gone again three days later. Anyone come across this before. Any pointers would be welcome. Starting to think wiring loom maybe