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5 Operation and maintenance
940 Professional IC Vario TWO (2.940.2100)
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63
2 Cleaning the parts of the piston cartridge
￭
If the zirconium oxide piston has become contaminated due to
abrasion or deposits, then clean it using a fine abrasive cleaning
powder, rinse it using ultrapure water until it is free of particles
and dry it.
The zirconium oxide piston must be replaced if it is heavily conta-
minated or scratched.
￭
Rinse the other parts of the piston with ultrapure water and dry
with a lint-free cloth.
3 Replacing the zirconium oxide piston
￭
Remove the retaining washer
from the old piston. If the
retaining washer sits too tightly, use a pointed object to loosen
the retaining washer.
￭
Assemble the retaining washer at the same point on the new pis-
ton.
4 Putting the piston cartridge together
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Insert the inner plastic sleeve, the spring and the spring retainer
into the piston cartridge.
￭
Slide the zirconium oxide piston carefully into the piston cartridge
until its tip emerges from the small opening of the piston car-
tridge.
￭
Attach the screw and tighten it by hand.
Mounting the piston
1 Reinserting the backup ring
wit ultrapure water and reinsert it.
2 Reinserting the piston cartridge
Screw the assembled piston cartridge back into the pump head and
tighten, first by hand, then also using an adjustable wrench by
approx. 15°.
Clean the second piston cartridge in the same way.
Mounting the pump head
Accessories
For this step, you need the following accessories:
You can find these parts in the accessory kit:
Vario/Flex Basic
(6.5000.000).
