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K&A - How To Change a Membrane

Changing the membrane in the valve block is a routine but critical maintenance task. 

This guide walks you through the full procedure to safely remove, clean, and replace the membrane on your 24-port K&A synthesizer main block.

There is also a video for this procedure here: K&A - Membrane Replacement

🔧 Tools and Supplies Needed

  • 3 mm Allen Wrench

  • 2.5 mm Allen wrench or Cordless power drill with 2.5 mm bit

    Power drill runs the risk of overtightening the screw.  Allen Wrench is recommended in most instances

  • 8 mm wrench

  • Guitar string or similar flexible wire

  • Lint-free wipes

  • ACN (acetonitrile) or ethanol

  • Replacement membrane

  • Spare caps for sealing chemical bottles when instrument is unpressurized

  • Replacement M3 screws and flangeless fittings (if needed)

  • Access to PC with K&A control software

⚠️ Warnings

  • Always fully shut down and depressurize the instrument before disassembly.

  • Use caution with chemicals—seal bottles if left open.

  • Do not overtighten screws or fittings. 

  • Use the correct torque setting on the drill to avoid damaging screw threads.

 

1. Shut Down and Prepare

  1. In the Software, open the Manual Control Screen and click SHUT DOWN.

  2. Follow all on-screen prompts until all the liquid is in their respective bottles.

  3. Double check to make sure no fluid remains in the liquid or waste lines.

  4. Once the lines are dry, close the Argon and Compressor Pressure Turn Valves

    WARNING: FAILURE TO DO THIS CORRECTLY COULD LEAD TO CROSS CONTAMINATION OF REAGENTS. NEVER TURN OFF COMPRESSOR PRESSURE UNTIL ALL BOTTLES HAVE BEEN DEPRESSURIZED

     

2. Secure Chemicals

  1. Remove all reagent and amidite bottle caps and seal the bottles with spare caps to prevent chemical degradation.

3. Disassemble the Manifold Block

  1. Remove the sheet metal loom above the column area using the 3.0 mm Allen Wrench

  2. Loosen the fittings on the main block, and fully remove the column inserts. Tape can be used to hold the lines in place after detaching.

    Hint: Take pictures and ensure the lines are fully labeled so that you return the fittings to the correct spot

  3. Use a 2.5 mm Allen wrench to begin loosening the manifold screws. A cordless drill (2.5 mm bit, torque = 0) can also be used to fully remove all screws.

    WARNING: It is very easy to strip the screws so use allen wrenches or bits that are not worn

  4. Inspect all screws—replace any with damaged heads.

4. Clean Components

  1. Remove the PEEK channel block and clean with ACN and a lint-free wipe.


  2. Clear all ports on the PEEK channel using a guitar string to remove debris or blockages.

5. Replace Membrane


  1. Remove the old membrane and align the new one so screw holes match the block pattern.

  2. Place the membrane beneath the PEEK channel block and the valve block—make sure the channels on the Peek Manifold face downwards. The channels should face the membrane.

  3. Insert the screws through the top manifold plate, using the holes to line up the membrane.

6. Reassemble Manifold Block

  1. Start one screw at each end by hand using the 2.5 mm Allen wrench.

  2. Lightly insert remaining screws starting from the center outward to evenly distribute torque 

  3. Tighten all screws by hand to finish—do not over-tighten.

🔁 Repeat this full process for any upper valve blocks or multiple membranes that need replacement.

7. Inspect and Replace Fittings

  1. Inspect male luer fittings under each column. Replace if needed.

  2. Use a guitar string to clear any new fittings before installing.

  3. Use an 8 mm wrench to reinstall and tighten all fittings.

  4. Replace damaged fittings with flangeless spares as necessary. Refer to this Video if a fitting replacement is needed.

8. Re-Pressurize and Test

  1. Turn the compressor air valve back on.

  2. Listen for leaks—tighten or replace fittings if needed.

  3. Reinstall the sheet metal loom and column adapters.

  4. On the PC, go to Control > Manual Control to verify tubing layout and placement of lines on the manifold.

  5. Reconnect reagent/amidite lines and prime all channels.

  6. Again inspect for liquid leaks.

Final Notes

  • Label the lines for easier placement,

  • This membrane change procedure helps maintain consistent flow and synthesis quality.

  • If you're unsure at any step, contact Sierra BioSystems Support or refer to your K&A service manual.

  • Consider logging the procedure in your maintenance records, including membrane part number and date changed.