Thanks for your replies. Will our service company be able to tell us if any parts are damaged from the overuse? The breakdowns have been due to various reasons - the fan that cools the drive malfunctioned, relays had to be replaced, the rollers needed replacing, etc. It seems a unlikely coincidence that these would all happen at once unless they are related to the construction. Is the dust a temporary problem? Or could it cause permanent damage to any parts?