Replacing The Piston Seals - Thermo Scientific Dionex UltiMate 3000 Series Operating Instructions Manual

UltiMate 3000 Series:
NCS-3500RS and NCP-3200RS

7.6.3 Replacing the Piston Seals

The seals prevent solvent from leaking into the rear seal wash system or into the pump
drive. This may cause unstable flow rates and baseline noise.
Each piston has two piston seals: One main piston seal (reversed phase) in the front part of the
pump head (→ Fig. 65, no. 7, page 184) and a piston seal in the plate of the rear seal wash
system (→ Fig. 65, no. 3). Use the piston seals only for the positions for which they are
intended. The (yellow) piston seals in the plate of the rear seal wash system are not intended
for use as main piston seals.
The replacement procedure for the main piston seals in the pump head consists of
1. Removing the pump head and pistons (→ page 188)
2. Disassembling the pump head and removing the pistons seals (→ page 195)
3. Cleaning the pistons (→ page 196)
4. Reassembling the pump head (→ page 197)
5. Recommended: Replacing the piston seals in the plate of the rear seal wash system
(→ page 199).
6. Installing the pistons and pump head (→ page 190)
7. After replacing the piston seals, observe the recommendations on page 200.
Tip: The pump is shipped with reversed phase main piston seals (RP).
Keep in mind that using chloroform, trichlorobenzene, methylene chloride,
tetrahydrofuran, or toluene as solvents chemically damages the UHMW-PE
seals. Chemical reactions may also occur when using tetrachloromethane,
diethyl ether, di-isopropyl ether, ketones, ammonium hydroxide, toluene,
methylcyclohexane, and monochlorobenzene. If you use these solvents, contact
the Thermo Fisher Scientific sales organization for Dionex HPLC Products.
Page 194 Operating Instructions