Grundfos SP 80-84
Grundfos Marine Pumps. Grundfos Marine pumps are horizontal, single-stage centrifugal pumps with suction and discharge connections at the same height. Available for marine/seawater applications in high-grade stainless steel (EN 1.4408, EN 1.4517) or titanium. Performance range: up to 1,300 m³/h, head up to 137 m, outlet sizes 1.25" to 10". Standards compliance: ISO 5199, EN 733, IS
Inspector Detail
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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
| Insulation resistance test | every 3-6 months and before extended lay-up |
| Strainer cleaning | typically each use in dirty bilge/ballast duty |
| Full pump/motor overhaul (bearings, seals, wear parts) | bauart-typical 15,000-25,000 running hours - confirm against the manufacturer's manual |
| Cable and gland inspection | annually |
Typical wear limits
| Impeller/wear ring clearance | typically 0.2-0.3 mm new, renew around 0.8-1.0 mm before efficiency loss becomes significant - confirm against the manufacturer's manual |
| Motor insulation resistance | investigate/replace when it falls below roughly 1 MΩ - confirm against manufacturer/class guidance |
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.
Components & Design
Component data being added…
Technical Data
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Common failures & inspection points
Visual inspection: leakage quantity 1-10 ml/24h is normal. If >20% water content in oil chamber after 1 week of operation, seal is defective. Seal faces NOT to be touched with bare fingers. At standstill: inject silicone oil between pump housing and coupling to prevent face adhesion.
Check circulation lubrication: relubricate SKF LGHP2 grease using grease gun. Measure bearing clearance with caliper per workshop guidelines. After 100,000 operating hours perform replacement. Motors up to 11 kW are permanently lubricated (no relubrication required). Abnormal vibrations/noise indicate bearing wear.
Visual inspection for: erosion, pitting, cavitation damage, cracks, dents or irregularities on impeller blade leading edges and hub. Inspect wear rings (front/rear) for scratches/deformation. Measure clearance between impeller and pump housing with caliper. Decrease in flow rate/pressure build-up/current consumption indicates impeller damage.
Motor to be inspected visually and cleaned regularly for adequate cooling. In dusty environments inspect more frequently. Monitor temperature (elevated heat development = early fault signal). Detect bearing wear through vibrations/noise. Compare current consumption vs. rated value. Motor bearings in 2/4/6-pole motors up to 11 kW are maintenance-free lubricated; larger motors to be lubricated regularly.
Check oil level after 1 week of operation (after seal replacement). Monitor water content: >20% water means seal failure. Oil change every 3,000 operating hours or 1x/year (Shell Ondina 917 or similar). Inspect oil colour, odour, turbidity for contamination/combustion products.
For seawater/marine environments: pump must be designed in high-grade stainless steel (EN 1.4517 Duplex, AISI 316) or titanium. Perform visual inspection for surface rust, pittings, discoloration. High-grade stainless steel designs (EN 1.4408) for T>40°C and chemical fluids. Use special seals (Super Duplex) and sealants for aggressive media.
Type-general inspection and maintenance points for this equipment category — not model-specific.
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