Replacing 1525EF Check Valves 72
4
4. Replace the entire old check valve assembly with a new one. Finger-tighten the new
check valve housing onto the pump head. Tighten the check valve with the 1/2-inch
adjustable wrench.
5. Hold the check valve housing with the 1/2-inch adjustable wrench. Reinstall the
tubing assembly. Tighten the compression screw with the 5/16-inch open-end
wrench while holding the assembly to prevent it from turning.
6. Repeat steps 2 through 5 to replace the other inlet check valves on the pump.
7. Prime the pump as described in Section 3.2.1 on page 48
. Check for leaks.
Replacing the Outlet Check Valve
1. Purge the pump with methanol. If methanol is not miscible with your current eluent,
use an intermediate eluent.
2. Run the pump until the indicator rod fully retracts into the pump head, then click the
Stop Flow button to turn 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 1/2-inch 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 (Figure 4-9
).
Figure 4-9 Disconnecting the Outlet Tubing (1525EF Pump)
STO
Attention:
Before starting this procedure, move the eluent reservoir below the pump
head level. This eliminates gravity flow of the eluent.
Pump Heads
Inlet Check
Outlet
Housing
Check Valve
Compression Screws
Valve Housing
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