How to Change the Needle on a G7167x Multisampler

This Information Applies To: Agilent G7167A/B Multisampler.

Issue:

Required when:

• The needle is visibly damaged.
• Leaks or blockages in the vialsampler are observed, especially between the needle and needle seat.
• The limit for the needle interaction EMF counter is exceeded.
• Replace the needle as part of yearly maintenance

Steps to follow:

Tools Required:

• 8710–0510 - Open-end wrench 1/4 - 5/16 inch

Parts Required:

• G4267-87201 - Needle assembly
  OR
• G4267-87210 - Needle assembly (slotted) for high injection volumes.
  

 See also: Needle & Needle Seats for HPLC

Warning: This procedure risks exposure to hazardous, toxic, or flammable solvents and reagents. Wear appropriate PPE as described in the material handling and safety data sheet supplied by the chemical vendor, and always follow good laboratory practice.

Warning: Risk of injury by uncovered needle. Do not open the safety cover of the needle station during normal operation. Wear appropriate PPE when removing the needle assembly.

It is recommended to always exchange the needle assembly and the needle seat at the same time to prevent premature leakage. Please see: How to change the needle seat on a G7167x Multisampler

1. Finish any pending or running acquisition job.

2. Stop the flow at the pump and remove the solvent lines from the eluent bottles to avoid spilling solvent.

3. Close the shutoff valves at the pump if available on your pump module.

4. Close any online sessions you have connected to the LC system. Open Agilent Lab Advisor Software, connect to your LC system then select Service and Diagnostics>Maintenance Positions>Change Needle, Loop, and Seat.

5, Click Start to start the maintenance task. Confirm the part number for the needle and needle seat listed in the pop-up configuration window match the new needle and needle seat being installed in the multisampler (Figure 1).

Figure 1 - Running the change needle maintenance task in Lab Advisor.

6. Open the Multisampler front door.

Warning: During normal operation of the Multisampler, the needle assembly has to be unlocked. Ensure that the needle is in the safety lock position before removing the needle assembly.

7. Lock the needle in the safety position by pulling down on the needle assembly (Figure 2).

Figure 2 - Locking the needle in the safety position.

8. Remove the needle assembly by slightly pulling the needle cartridge (Figure 3).

Figure 3 - Removing the needle assembly

Caution: Risk of damage to the loop capillary. During the next steps, the loop capillary is still connected to the needle assembly. The loop capillary may be damaged if the loop is stretched or bent too far. Replace the sample loop if the plastic adapter is damaged. Note: Do not open the rear plastic clamp.

9. Remove the loop plastic adapter (Figure 4).

 Figure 4 - Removing the loop plastic adapter.

10. Use the 1/4-inch wrench to loosen the fitting of the loop capillary, then remove the capillary from the back of the needle assembly. (See Figure 5)

Figure 5 - Loosening the fitting of the loop capillary.

11. Remove the needle assembly. (See Figure 6)

Figure 6 - Removing the needle assembly from the loop capillary.

 12. Install the loop capillary on top of the new needle cartridge (1) and tighten the fitting hand tight (2). Use a 1/4-inch wrench to tighten the fitting of the loop capillary (Figure 7).

Caution: Do not overtighten the fitting. A quarter turn should be sufficient.  If the needle is changed, we recommend changing the needle seat as well to ensure a good seal between the needle and needle seat. Please see: How to change the needle seat on a G7167x Multisampler

Figure 7 - Connecting the new needle assembly to the loop capillary.

 13. Install the loop plastic adapter. Verify the sample loop info on the plastic adapter. For a single needle, the default position is on the right. For dual loop autosamplers, a left or right sample loop must be installed in the correct slot of the needle parkstation (Figure 8).

Figure 8 - Installing the loop plastic adapter.

 14. Pinch and re-insert the needle assembly and the connected loop capillary into the z-arm coupler (Figure 9).

Caution: Check the tension of the loop capillary. It must be forced and guided to the hydraulic box to prevent it from being caught by the z-drive.

 

Figure 9 - Re-insert the needle assembly into the z-arm coupler.

15. Close the front door of the multisampler.

 16. In Agilent Lab Advisor software close the Change needle/loop>End, click End and wait until the needle assembly is in the needle park station. If using the local controller (Instant Pilot) close Change needle/seat.

 If possible, run a system pressure test with the port 6 of the injection valve blanked using the appropriate blanking nut to ensure the vialsampler flow path is pressure tight to a pressure higher than your application requires.

 Cause: Over time deposits can block the needle and the needle seat causing pressure issues and leaks. Also wear and tear of the needle against the seat during normal operation eventually causes damage to both assemblies, requiring replacement.