Waters 1500-Series, Operator'S Manual

Page: 115 / 188

Replacing and cleaning plunger seals and plungers 5-7
To remove a pump head:
1. Purge the pump with methanol (see Chapter 4 ).
Requirements:
• If your eluent is not miscible with methanol, use an intermediate
eluent.
• Move the eluent reservoir below the pump head level to prevent
gravity flow of the eluent.
2. Insert the priming syringe into the Luer fitting at the center of the
draw-off valve handle, and then turn the handle counterclockwise about
1/2-turn to open the valve.
3. Use the syringe to withdraw all methanol.
4. Use the data control software to set the flow rate to 0.3 mL/min and to
initiate pump flow.
5. When the indicator rod fully retracts into the pump head, use the
software to stop the flow, turning off the pump.
Tip:
This action ensures that the weight of the pump head does not rest
on the plunger while you remove the head.
6. While using the adjustable wrench to hold the check valve housings in
place, use the 5/16-inch open-end wrench to remove the inlet and outlet
tubing from the check valves on the pump.
7. Holding the pump head against the pump, use the 5/32-inch Allen
wrench to remove the two, pump-head-assembly mounting screws.
Tip:
Loosen the screws 1/2-turn at a time for the first two turns.