Replacing A Pump Piston - Thermo Scientific Dionex Easion Operator's Manual

To reinstall the pump head and piston:
Thermo Fisher Scientific recommends reinstalling the pump head and piston as a
single assembly, so that the piston centers itself onto the magnetic follower.
1. Hold the assembled spacer and guide with the drain tube aligned vertically,
and then press the spacer into the pump head until it is flush with the indented
surface of the head.
2. Insert the piston so that about 6 mm
(1/4 in) of the shaft remains exposed. This
ensures that the magnet in the follower
picks up the piston. (The follower is the
cylinder that holds the piston in place as it
moves in and out of the pump head
assembly.)
3. Reinstall the pump head and piston
assembly. Tighten the screws evenly.
To complete the procedure:
1. Reconnect all liquid lines to the pump head.
2. Close the waste valve knob.
3. Turn on the Dionex Easion power switch.
4. Prime the pump (see
5.9

Replacing a Pump Piston

Continued leaking of the piston seal after installation of a new seal (assuming the
pump head is tight) indicates a dirty, scratched, or broken piston.
Follow the instructions in
piston seal (P/N 055870). Always replace the piston seal when replacing a piston.
Doc. 155028-01 08/20
Section 3.6).
Section 5.8 to install a new piston (P/N 052840) and
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