Waters 1500-Series, Operator'S Manual

Page: 126 / 188

5-18 Maintaining the HPLC Pump
Replacing the 1525EF outlet check valve
To replace the outlet check valve:
1. Purge the pump with methanol (see Chapter 4 ). If methanol is not
miscible with your current eluent, use an intermediate eluent.
2. Use the data control software to run the pump until the indicator rod
fully retracts into the pump head, and then stop the flow, turning off the
pump.
This ensures that the weight of the pump head does not rest on the
plunger when you remove the pump head.
3. Use the adjustable wrench to hold the housings in place. Use the
5/16-inch open-end wrench to loosen the compression screws and remove
the inlet and outlet tubing assemblies from the check valve housings.
Disconnecting the outlet tubing (1525EF pump)
4. Use the adjustable wrench to loosen the outlet check valve housing.
5. While holding the pump head in place, use the 5/32-inch Allen wrench to
remove the two pump head assembly mounting screws. Loosen the
screws 1/2-turn at a time for the first two turns.
Pump heads
Outlet
housing
check valve
Compression screws
Inlet check
valve housing