Gilson 402 User Manual page 92

Maintenance
Piston rod
Piston button
Allen screw
Piston nose
Nose holding
tool
Allen screw
Piston button
Piston rod
Support collar
Piston nose
Syringe barrel
Valve screw
6-8
1. Remove the syringe from the pump as described
in Chapter 4.
2. Slide the piston out of the syringe barrel.
3. Remove the piston nose from the piston rod by
carefully pinching the piston nose with a pair of
cutters and gently pulling the piston nose off the
piston rod. Take care not to damage the end of
the piston rod when removing the nose. (It is
possible to remove the nose by pinching it between
the thumb and forefinger nails and pulling.)
4. Remove any remaining debris of the original
piston nose from the end of the rod.
5. The 100 µL and 250 µL pistons have a narrow
rod that may be damaged if handled incorrectly.
In order to fit a new piston nose without unduly
bending the piston rod, undo the Allen screw that
secures the piston button to the piston rod. Slide
the button down the piston rod to within 10 mm
of the end of the rod where the new piston nose
is to be mounted and re-tighten it in position.
6. Put the new piston nose in its recess in the piston
nose mounting tool. The 100 µL and 250 µL
piston noses use a common tool. One face of the
tool has a recess for the 100 µL piston nose, the
other face has a recess for the 250 µL piston nose.
7. Hold the piston button and gently push the end
of the piston rod into the new piston nose.
8. Remove the piston assembly from the piston
nose holder. Slacken the piston button and slide it
away from the piston rod.
9. Dip the piston nose in distilled water and slide
the piston assembly into the syringe.
10. Hold the syringe upright with the threaded end
of the syringe resting on a flat, clean surface.
Slide the piston into the syringe until the piston
stops (the nose is level with the end of the syringe).
11. For the 100 µL piston only, insert the support
collar. The support collar should be replaced
after around 60 000 strokes.
12. Slide the piston button against the body of the
syringe and tighten the Allen screw that secures
the piston button onto the piston rod.
13. Slide the piston up and down in the syringe five
or six times to ensure a smooth operation between
the piston and syringe.
14. Remount the syringe on the pump as described
in Chapter 4.
6