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Thermo Fisher Scientific

Switching valve causing over pressure


My switching valve is causing over pressure (MSA application).


Ion Chromatography


  1. Does your valve have corrosion like the images shown?
    MSA1.png MSA2.png

  2. Yes? Replace with part numbers (can try rebuilding, 075973 or just replacing the pod, 075971, before ordering entire valve assembly).
     Part Number Description  Revision 
     069561  VALVE,6PORT,PK,TITAN,I2C  B
     075971  VLV POD ASSY,6 PORT,RHEO,PK,6K  B
     075973  KIT,REBUILD, VLV, 6-PORT,6K  B

  3. No? Follow the steps below.
    1. Check system pressure of the system before the load/inject valve, disconnect tubing from port 2 or P. Turn pump on and record pressure.
    2. If normal pressure, disconnect port 3 or C so only the valve is inline, not the columns. Record the pressure.

    3. You should not see much of a pressure increase.
    4. If you do, take the valve apart and clean rotor and stator by taking 3 Allen screws off from valve front
      pooling - image 03.png
    5. Remove the rotor and stator and sonicate in 50/50 methanol/DI (picture below)
      pooling - image 04a.png pooling - image 04b.png

    6. Make sure you can see light through 6 small openings in stator. (round disc). Also verify you can see light through stator face (the tan colored piece where you took off the allen screws, look through all 6 ports from front to see light.)

      pooling - image 05.png
    7. If you cannot see light through the ports, hook up syringe or pump and clear blockage of stator.
    8. Once you have verified no blockages in the valve reassemble the valve and hook a fluid connections back up and run step 6 again.
  4. If pooling still occurs please call Tech Support.


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