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Thermo Fisher Scientific

Clogged flow path

Issue

The components in the autosampler flow path are clogged. 

Environment

Vanquish Split Samplers:

  • VC-A12-A-02
  • VC-A13-A-02
  • VF-A10-A-02
  • VF-A40-A-02
  • VH-A10-A-02
  • VH-A40-A-02

Resolution

Be Advised:

  • Turn off the pump flow to the autosampler.
  • Wait until the system pressure is down to zero.
  • Be sure that no backpressure from other modules in the system is present.

 

Troubleshooting Steps:

1. Move the needle unit into service position and secure the needle unit.

2. Slightly loosen the screw that attaches the sample loop plate with the screwdriver.

3. The screw can remain loosely screwed on the holder for the sample loop unit. Disconnect the sample loop fitting from the needle unit.

clipboard_e49fdc1d9541b6cda82f093a20d4dc4b9.png

Figure 1: Sample loop

Components of the sample loop:

  • Sample loop fitting on the needle unit 
  • Sample loop
  • Sample loop plate
  • Attachment screw for plate
  • Recess in the sample loop plate
  1. Push the sample loop unit slightly upward so that the screw matches the large recess in the sample loop plate.

  2. Remove the sample loop unit from the needle unit.

 

clipboard_e2565348d1da37167f78503b119087af8.png

Figure 2: Remove sample loop unit

  1. Disconnect the sample loop fitting from the metering device head.
  2. Place the open connector of the sample loop unit into the waste reservoir.
  3. Set the injection valve to Inject position if the valve is not yet in this position.
  4. In Chromeleon, set the pump flow rate to the maximum pump flow rate.
  5. Turn on the pump flow and flush the sample loop to waste at the maximum pump flow rate for approximately 1 minute. Afterward, turn off the pump flow.
  6. Connect the sample loop fitting to the metering device head.
  7. Connect the sample loop fitting to the needle unit.
  8. Hang the sample loop plate to the holder for the sample loop unit:

      a) Hook the screw hole of the sample loop plate onto the attachment screw. Make sure that the screw is loosened.

      b) Align the long recess in the plate with the holder.

  1. Position the sample loop capillary coming from the needle unit connection so that the capillary leaving the connector points to 6 o'clock. 
  2. Slightly tighten the attachment screw for the sample loop plate with the screwdriver.
  3. Do not fully tighten the screw yet.
  4. Tighten the attachment screw for the sample loop plate with the screwdriver.

clipboard_e2dd9b587a8db0f82b24ff1ab85127ced.png

Figure 3: Aligning the sample loop unit to the screw

  1. Loosen the shipping lock screw above the needle unit: Turn the captive screw counterclockwise until it hangs loosely in its spring. The use of a slot screwdriver may facilitate turning the screw.
  2. Push the SERVICE button and wait until the needle moves up.
  3. Push the SERVICE a second time to move the needle unit slightly along the horizontal needle drive into the sample compartment until it is positioned above the wash port.
  4. Turn on the pump flow and flush the needle unit into the wash port at the maximum pump flow rate for approximately 1 minute. Afterward, turn off the pump flow.
  5. Push the SERVICE button a third time. The needle will move into the carousel and back until it descends back into the needle seat.
  6. On the column or column pre-heater, disconnect the capillary. The capillary remains connected only to the injection valve.
  7. Flush the needle seat, injection valve and capillary to the column or column pre-heater to waste at the maximum pump flow rate for approximately 1 minute.
  8. Afterward, turn off the pump flow.

NOTE: Observe whether the sample loop can move freely. If it does not move freely: Readjust the sample loop by positioning the sample loop capillary coming from the needle unit connection so that the capillary leaving the connector points to 6 o'clock. Repeat the test until the loop moves freely.