We found that the temp in EY was not holding steady over the weekend. The heating coil for the space was commanded on but was not running. After investigating, we found that the line voltage fuse in Phase C had blown which was keeping the variable transformer from operating. We took the variable transformer out of the circuit and swapped fan relay contacts to run the elements not controlled by the variable transformer. Heating elements are currently working and EY is slowly heating up. The heating elements controlled by the variable transformer will need to have their resistance checked for a short or an open circuit during the maintenance window.