SP 80-84

Common issues

• Motor bearing wear from seawater ingress or lubricant breakdown in the submerged section
• Impeller and diffuser wear from sand, sediment or debris in bilge/ballast water
• Cable gland or motor seal failure allowing water into the stator windings
• Reduced flow or head from a clogged strainer or fouled impeller
• Overheating trips from dry running or operation against a closed discharge valve
• Corrosion of stainless components after prolonged seawater/bilge chemical exposure
• Insulation resistance degradation over time, tripping earth-fault protection

Inspection checklist

• Insulation resistance (megger) test of motor windings before and after use
• Check strainer/suction screen for debris and clean as required
• Check discharge pressure and flow against the pump curve at a known duty point
• Inspect power/control cable and gland for damage, chafing or corrosion
• Check running current against the nameplate rated current
• Verify non-return valve operation on the discharge line
• Inspect impeller and diffuser stages for wear/erosion at overhaul
• Check motor bearing noise and axial/radial play at overhaul

Service intervals

Typical wear limits

Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.

Critical spares

• Motor bearing set (upper and lower)
• Mechanical shaft seal / cable entry seal kit
• Impeller and diffuser stage set (wear parts)
• Power cable with pre-moulded gland
• Discharge line non-return valve
• O-ring/gasket kit for the motor housing

Safety

• Handling a submersible pump requires lifting gear rated for its wet weight; secure the lifting point before lowering into a tank or well
• Electrical isolation and lock-out before withdrawal from the pit or tank
• Confined/enclosed space entry precautions when accessing bilge wells or pump pits
• Risk of water hammer if the discharge valve is closed rapidly at full flow

Class survey

Bilge/ballast submersible pumps are typically covered under Continuous Survey Machinery; class looks for a satisfactory operational test (flow/pressure), insulation resistance records, and confirmation that bilge alarms and pump interlocks function correctly.

Estimated lifetime: Bauart-typical submersible pump sets of this size run 20,000-40,000 hours before major overhaul in continuous bilge/ballast duty, depending on water quality and duty cycle - confirm against the manufacturer's manual.