What to consider
Climbing depends on cleaner design, pool geometry, surface condition, traction, cleanliness, and available suction or pressure. Not every cleaner is designed to climb every wall, step, bench, or waterline.
Confirm the design expectation
Review the model's manufacturer instructions to confirm whether wall, step, or waterline cleaning is an intended capability. A floor-focused cleaner is not defective simply because it does not climb.
Inspect traction and cleanliness
Visible wear on tracks, wheels, or brushes and an overloaded filter or bag can change climbing behavior. Slick buildup, algae residue, or a particular finish may also affect traction without proving a cleaner fault.
Consider flow and pool geometry
Suction or pressure that differs from normal can affect circulation-driven cleaners. Tight transitions, ledges, step shapes, drains, and wall angles can create repeatable limitations even when the cleaner otherwise operates.