This gallery should document both crawlspace areas (including the one without an extraction point and the one with a pipe running under the slab), the pipe system running underground, and the external fan unit.   Close-up shots of the fan label or casing are necessary, even if the model isn't marked, to support accurate replacement. Photos of the surrounding layout and exit points will guide the fourth extraction point addition and the new fan installation. Make sure to include angles showing pipe routing underground to the exterior.