Hi, I have a similar propblem with my boiler. I have an ideal isar that is only 9 months old. The other day my son heard grinding noises coming from it when he switched the central heating on. He was quite worried about the noise and decided to switch the boiler of, as a precaution. He told me the problem when I come home, so I thought I would have a look. I switched the boiler on and it suddenly made a huge bang. (it scared the life out of me) I quickly switched it of and don;t want to take the risk of testing it again. Do you think this is the same problem featured above. Should I contact my local plumber or should I call isar back. Many Thanks, Nick