M6-MFM

Common issues

• Gasket hardening or shrinkage over time leading to inter-plate leakage
• Fouling/scaling on the seawater side reducing heat transfer efficiency
• Biofouling (marine growth) in seawater-cooled circuits, especially in warm-water trading
• Plate corrosion/pitting from chloride attack if plate material or water treatment is inadequate
• Gasket carrier groove corrosion affecting gasket seating
• Cross-contamination between circuits from a failed plate/gasket, mixing freshwater and seawater sides
• Uneven flow distribution from partial blockage causing localised overheating or fouling
• Tie-bolt corrosion or seizure making plate pack disassembly difficult

Inspection checklist

• Check for external leakage at the gasket edges/observation ports between plates
• Monitor the temperature approach (inlet/outlet delta) against the commissioning baseline for signs of fouling
• Inspect the plate pack tightening dimension against the manufacturer's specification for the fitted plate count
• Open and inspect plates for scaling, biofouling, pitting, and gasket condition at scheduled intervals
• Check the seawater side for marine growth and confirm any biocide/anti-fouling dosing is functioning
• Inspect gasket carrier grooves for corrosion before re-gasketing
• Verify pressure drop across the exchanger against baseline to detect partial blockage
• Check the frame, tie bolts, and support feet for corrosion and correct torque
• Confirm no cross-contamination by checking for oil/coolant traces on the opposite circuit's discharge

Service intervals

Typical intervals for this design class, not the manufacturer’s figures for your model. The manufacturer’s manual is binding.

Typical wear limits

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

Critical spares

• Full gasket set for the plate pack (correct elastomer for the service, e.g. NBR/EPDM/Viton)
• Individual replacement plates (a small stock is normal since occasional plate damage/pitting is expected)
• Tie bolt and washer set
• Frame plate seals

Safety

• Pressurised system up to the unit's design pressure (16 bar for this model) - fully depressurise and isolate before opening
• Hot surfaces where the unit handles high-temperature circuits (rated to 110 C for this model) - allow cooling before opening
• Heavy plate pack components - use proper lifting/handling technique when opening large plate counts
• Incorrect re-tightening can cause gasket blow-out under pressure - always tighten to the manufacturer's dimension, not by feel

Class survey

Central coolers are normally covered under Continuous Survey Machinery. Class checks for records of periodic opening/inspection, any plate replacements, and pressure test results after re-assembly, particularly where the unit forms part of the sea water cooling system for classed essential machinery.

Estimated lifetime: Not meaningfully expressed in running hours. Plate heat exchanger frames typically remain in service for the vessel's operating life with periodic re-gasketing and occasional plate replacement; plate and gasket life depends heavily on water quality, chloride content, and biofouling control rather than a fixed hours figure.