When checking clearances, what is important to do with the impellers?

When checking clearances with impellers, it is crucial to rotate them through 360 degrees. This allows for a comprehensive assessment of the clearance at various points around the impeller. As impellers can be subject to tolerances and may not be perfectly symmetrical, rotating them fully enables the millwright to identify any potential issues, such as uneven wear or misalignment, that may not be apparent in a stationary position or a partial rotation. By observing the full rotation, the millwright can ensure that all areas of the impeller have adequate clearance, which is essential for optimal performance and longevity of the machinery.