Waters Prep Series Installation And Maintenance Manual page 135

Cleaning check valves
Clean check valves by running a nonionic detergent solution or 6N HNO
through the pump heads. Flush with copious amounts of water to remove
residual detergent or acid.
Disconnect the column from the flow path. If the pump outlet is connected
Tip:
directly to the column (for large-scale operation), disconnect the column at its
inlet from the flow path.
For the PrepLC system, if the front panel is connected in the flow path,
Tip:
turn the Purge valve on the front panel to Purge.
For the Delta-Prep system, turn the Purge valve on the column to Purge.
Tip:
To clean the check valves:
1. Fill the solvent reservoir with a compatible cleaning solution like
methanol:water (1:1) with liquid detergent or 6N HNO
2. Set the flow rate to 3.0 to 4.0 mL/min, and purge for 10 minutes.
3. Replace the contents of the solvent reservoir with water.
4. Set the flow rate to 3.0 mL/min and purge for 10 minutes.
Replacing check valves
If the previous procedure does not sufficiently clean the check valves, remove
the check valves from the pump as described next and check them for damage.
If none is apparent, put them in methanol, in an ultrasonic bath, for 10
minutes. If a part is damaged, replace it as necessary.
Disassembling inlet check valves
To disassemble the inlet check valves:
1. Shut down the controller, and disconnect the power cord. The
proportioning valve stops all solvent lines.
2. Disconnect the inlet tubing from the inlet check valve, and loosen the
inlet check valve with a 1/2-inch open-end wrench.
3. Remove the inlet check valve housing assembly from the pump head,
and disassemble it by tipping the housing upside down.
Check the retainer cup and the ball-and-seat assembly for damage or
debris.
added.
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Maintenance procedures
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