Maintaining the 1525 Pump
55
4
10. After 2 minutes, record the pressure (P1). One minute later, record the pressure
again (P2). Calculate head pressure decay with the formula (P1 – P2)/P1. Verify that
head pressure decay is 0.15 or less. If the pressure decay for the pump head is
greater than 0.15, you may have bad check valves. Remove and clean or replace
the inlet and outlet check valves (see
Section 4.4, Replacing 1525µ Check Valves
11. Relieve head pressure by slowly opening the reference (or vent) valve.
12. Disconnect the right pump head outlet tubing from the draw-off valve. Transfer the
compression plug from the left port of the draw-off valve to the right port of the
draw-off valve. Reconnect the left pump head outlet tubing to the left port of the
draw-off valve.
13. Repeat steps 5 through 12 to test the left pump head.
14. Remove the compression plugs from the draw-off valve and the tee. Reconnect the
right pump head outlet tubing. Reconnect the tubing from the pulse dampener.
15. Repeat steps 3 through 14 on pump B. In step 3, disconnect pump A from the tee.
16. When finished, purge the pump with eluent and close the reference (or vent) valve.
17. Remove the compression plug from the reference (or vent) valve and reconnect the
outlet tube to the system.
4.3 Replacing 1525µ Plunger Seals and Plungers
This section describes how to:
•
Remove and replace plunger seals and plunger bearings
•
Remove and replace plungers
The plungers in a Waters 1525 Pump are ultrasmooth, chemically inert sapphire rods. Salt
crystals that precipitate out from the eluent can form on the plunger and cause wear on
the plunger seals and on the plunger itself. The result is a slow leak and a slight cyclic
pressure fluctuation, with a possible increase in retention time.
For continued high performance of the pumps:
•
Replace the plunger seals and bearings twice yearly, or as needed.
•
Replace the plunger twice yearly, or as needed.
•
Clean and inspect the plunger twice yearly (or sooner if using abrasive eluents).
4.3.1 Preparing for Plunger Seal Replacement
Required Materials
•
5/16-inch open-end wrench (in Startup Kit)
•
5/32-inch Allen wrench (in Startup Kit)
Summary of Contents for 1525EF
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