Waters 1500-Series, Operator'S Manual

Page: 122 / 188

5-14 Maintaining the HPLC Pump
8. Carefully slide the pump head over the plunger and onto the pump.
9. Holding the pump head securely against the pump, alternately tighten
the two screws.
10. Check for even head alignment by observing the gap between the pump
head and the pump head support assembly.
11. Use the data control software to set the flow rate to 1.0 mL/min and
initiate pump flow.
12. Verify the pump head alignment.
• For 1525µ pump, observe the movement of the indicator rod while
the pump is running.
• For 1515/1525 pumps, pull out and release the indicator rod.
• If the rod does not move smoothly (or snap back easily), the head is
misaligned. Stop the pump, loosen the pump head, and then repeat
step 8 through step 11 .
• If the rod moves smoothly (snaps back easily), use the software to
stop the flow, turning off the pump. Continue with step 13 .
13. Using the adjustable wrench to hold the check valve housings in place,
reconnect the inlet and outlet tubing assemblies to the pump head.
Tighten the tubings using the 5/16-inch open-end wrench.
14. Prime the pump as described in Chapter 4 . If you notice leaks, verify
pump head and plunger seal installation (see page 5-6 ).
Replacing check valves
This section describes how to replace the pump’s inlet and outlet check valves
for the 1515/1525 pumps, 1525EF pump, and the 1525µ pump.
Recommendations:
• Replace the inlet and outlet check valves every 6 months, or more
frequently if required by your application.
• Keep a spare set of new check valves on hand.
Caution:
To avoid breaking the plunger, hold the pump head
securely against the pump.