Replace needle O-ring and check needle (obsolete)

For assembling and disassembling the special needle holder tool TLAX110023 and spanner TLAX110026 are needed.

Needle removal

1. Remove drip tray (metal sheet under needle unit, behind door)
2. Disconnect both tubes.
3. Loosen the knurled knob.
4. Remove the complete needle assembly outside the instrument.
5. Clean the needle with a disinfectant.

O-ring replacement

1. Use the needle tool TLAX110023 to loosen the outer needle from the needle holder.
   Warning: Be aware of spring tension
2. Store outer needle in tool TLAX110023.
   
3. Remove the spring QWVR0012260.
4. Loosen TLAX090012 O-ringscrew from the needle holder.
5. Remove the O-ring QWLV050002.
6. If needed: Grease the outside of the inner needle base by removing TLAX090011 (use acid free vaseline).
7. Fit a new O-ring QWLV050002 carefully, and press the O-ring into the recess.
8. Place the O-ring screw over the inner needle so that the internal hexagonal hole is facing the inside of the needle holder.
   • The small hole in the O-ring screw should stay about 2 mm above the holder.
9. Place the spring QWVR012260 over the inner needle, insert the special O-ring screw spanner TLAX110026, and tighten the O-ring screw slightly.
   • Hold the needle assembly block tight and turn just the spring clockwise.
10. Insert the outer needle carefully into the needle tool TLAX110023, place the inner needle, without damaging the inner needle tip, straight through the outer needle.
11. Hold the spanner TLAX110026 in one hand, and tighten (hand-tight) the outer needle by turning the needle tool TLAX110023 clock-wise.
12. Remove the spanner TLAX110026, hold the needle assembly by the assembly block, and tighten the outer needle firmly with TLAX110023.
13. Check if the pipes are facing the same direction.
14. Compress the needle assembly, it should move smoothly.

Check for leakage

1. Check the needle assembly for leakage by short-circuiting both ends of the outer needle with a short length of tubing.
2. Connect a syringe with air to the inner needle and immerse it in water.
3. Pressurize it with the syringe - air bubbles should not be visible.
4. Dry all parts.

Needle assembly

1. Place the needle back on the instrument.
2. Fasten the knurled knob, do not fasten too tight
3. Connect both tubes to the needle.
4. Place drip tray.