Gilson Pipetman Ultra U2 User Manual page 18

PIPETMAN
To access the O-ring, remove the tip-ejector and un-
screw the lower part of the tip-holder - if the O-ring is
not immediately visible on the piston, set the pipette
to its maximum volume, then press the push-button
to the second stop. You should now be able to remove
the O-ring from the piston. Sometimes, the O-ring may
be found in the recess at the top-end of the lower part
of the tip-holder.
If required lubricate the piston (see "How to Lubricate
the Piston") then fi t a new O-ring by sliding it onto the
piston. Reassemble the pipette.
The dimensions of the O-ring vary according to the
pipette model - refer to "Spare Parts" for details.
Servicing the Piston
You may remove the piston-assembly to clean, lubri-
cate, or change the piston.
The specifi cations of the pipette must be checked
after changing the piston (see Chapter 16).
Removing the Piston
1) Set the volume to zero and lock the pipette. Do not
unlock the pipette or try to reset the volume while
changing the piston assembly.
2) Remove the tip-ejector and (optionally) the lower
part of the tip-holder.
If you remove the lower part, take care to remove the
O-ring as described in "Changing the O-ring".
3) Unscrew the connecting-
nut (turn by hand, counter-
clockwise).
4) Pull on the spring guide to remove the piston
assembly from the body of the pipette - separate
the parts (see below).
For U5000 and U10 ml, the connecting nut is com-
bined with the upper part of the tip-holder (see "Spare
Parts").
5) Clean and autoclave (if required) the piston and
holder, together with any other parts that may
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