Metrohm 942 Extension Module Vario Manual page 51

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Accessories
942 Extension Module Vario ONE/Deg (2.942.1060)
Rinse the other parts of the piston with ultrapure water and dry
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with a lint-free cloth.
3 Replacing the zirconium oxide piston
Remove the retaining washer (19-2) from the old piston. If the
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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-
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ton.
4 Putting the piston cartridge together
Insert the inner plastic sleeve, the spring and the spring retainer
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into the piston cartridge.
Slide the zirconium oxide piston carefully into the piston cartridge
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until its tip emerges from the small opening of the piston car-
tridge.
Attach the screw and tighten it by hand.
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Mounting the piston
1 Reinserting the backup ring
Clean the backup ring (15-3) 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
For this step, you need the following accessories:
4 mm hex key (6.2621.030)
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5 Operation and maintenance
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