Plate Gasket Replacement

When to Replace Gaskets

• Visible leakage: External leaks between plates or at the frame indicate gasket failure.
• Cross-contamination: If fluids are mixing between channels, a gasket has failed internally.
• Age: Replace gaskets every 3 to 5 years for NBR, 5 to 7 years for EPDM, depending on operating temperature.
• Performance drop: If the exchanger cannot maintain duty and fouling is not the cause, internal gasket leaks may be bypassing fluid.
• After disassembly for cleaning: Always replace gaskets when the exchanger is opened for cleaning. Reusing old gaskets risks leaks.

Replacement Procedure

1. Isolate the heat exchanger. Close both inlet and outlet valves. Lock out and tag out.
2. Drain both sides completely. Verify no pressure remains.
3. Mark the plate stack order before opening. Take photos for reference.
4. Loosen the compression bolts gradually in a cross pattern. Do not remove one side completely before the others.
5. Open the frame. Remove the plates one at a time, keeping them in order.
6. Inspect each plate for cracks, corrosion, and distortion. Replace damaged plates.
7. Remove old gaskets. Clean the gasket groove thoroughly. Remove all adhesive residue if the gaskets were glued.
8. Install new gaskets. Ensure they are the correct material for the fluid and temperature. Press into the groove evenly.
9. If using glue-bonded gaskets, apply adhesive sparingly and allow it to cure per the manufacturer's instructions.
10. Reassemble plates in the correct order. Follow the plate arrangement diagram. First plate, second plate, etc.
11. Close the frame. Tighten bolts gradually in a cross pattern.
12. Measure the gap between the frame plates. Compare to the manufacturer's specified dimension. Adjust bolt tension until the gap is correct.
13. Pressurise slowly and check for leaks.

Common Mistakes

• Wrong plate order: Plates must be assembled in the correct sequence. Each pair of plates forms a channel. Wrong order disrupts flow paths.
• Over-tightening: Compressing too far crushes gaskets and distorts plates. Always use the specified gap measurement, not bolt torque.
• Reusing old gaskets: Old gaskets have taken a set and will not seal properly when reassembled. Always use new gaskets.
• Mixing gasket materials: Different gasket materials (NBR, EPDM, Viton) may look similar but have different compression characteristics. Use one material throughout.
• Not cleaning the groove: Old adhesive or gasket material left in the groove prevents the new gasket from seating properly.