S series (centrifugal housing fan, RG / RD)

Corrosion check: Inspect impeller, housing, and shaft for salt water corrosion, pitting, and paint/coating damage — especially after voyages in high-humidity or salt-spray environments

Bearing condition: Check for unusual noise, vibration, excessive temperature rise, and lubricant condition; re-grease or replace sealed bearings per manufacturer intervals

Impeller balance and blade integrity: Inspect blades for fouling, erosion, cracks, or deposits; clean and re-balance if vibration levels exceed ISO 10816 limits

Motor insulation and electrical connections: Measure insulation resistance (Megger test) on motor windings; inspect terminal connections for moisture ingress, oxidation, or loose contacts

Belt drive / coupling inspection (where applicable): Check belt tension, wear, and alignment on belt-driven units; inspect flexible couplings for rubber degradation or misalignment

Filter and inlet screen cleaning: Remove and clean inlet protective screens or filters; replace if permanently fouled to prevent restriction of airflow and overloading

Housing and ductwork seal integrity: Check gaskets, bolted flanges, and flexible connections for air leaks, deformation, or loosened fasteners that reduce system efficiency

Vibration and mounting inspection: Verify anti-vibration mounts are intact and not hardened/cracked; check all hold-down bolts for tightness, particularly after heavy weather or shock loads