This paper is a report on the results of a usability study where Augmented Reality (AR) was used for giving instructions on how to start up a diathermy apparatus (DA). The main question in focus was if the AR system would be accepted as part of the technological support by a user group consisting of professional medical personnel. It was found that all users but one could solve the task at hand when aided by the instructions given in the AR system. The interviewed responded that they preferred personal instructions from an experienced user, sometimes in combination with short, written instructions, but also that they appreciated the objective instructions given by the AR system. Despite the reported problems, the users were positive towards AR systems as a technology and as a tool for instructions in this setting. This indicates that AR could be part of a future training resource for new staff, which does not demand the time of a trained professional.