A dirty check valve causes erratic flow rates and pressures. In addition, it may cause the pump to lose prime and/or be difficult to reprime. Replace dirty check valves whenever possible. However, if new check valves are not available, follow the instructions below to clean the valves.

Procedure

  1. Turn off the pump from the Chromeleon CDS ePanel.
  2. Turn off the Dionex Inuvion IC System main power switch on the rear panel.
  3. To prevent contamination of pump parts, put on standard disposable laboratory rubber gloves (powder-free, particle-free, and oil-free) before disassembling the pump head.
  4. NOTE

    Never disassemble the pump head with bare hands. Contamination from tiny particles of dust or dirt on the check valves or piston can affect the inside of the pump head, leading to poor pump performance.

  5. Disconnect any tubing and fittings from the inlet and outlet check valve assemblies on the pump head (see the following image).
  6. Pump components
    Figure Pump components
  7. NOTE

    The inlet check valve assembly housing has a 1/4-28 port. The outlet check valve assembly housing has a 10-32 port (see the following image).

  8. Inlet and outlet check valve assemblies
    Figure Inlet and outlet check valve assemblies
  9. Using a 1/2-inch wrench, loosen both check valve assemblies. Remove the check valve assemblies from the pump head.
  10. Remove the cartridges from the housings.
  11. For the inlet check valve:
    - Place a new cartridge (P/N 045994), with the double-hole end of the cartridge visible, in the housing.
    - Install the check valve assembly on the bottom of the pump head.
  12. For the outlet check valve:
    - Place a new cartridge, with the single-hole end visible, in the housing.
    - Install the check valve assembly on the top of the pump head.
  13. If you are installing new cartridges (P/N 045994) in the existing check valve housings:
  14. When placing the cartridge in the inlet check valve housing, make sure the double-hole end of the cartridge is visible. If it is not, remove the cartridge from the housing and install it correctly.
  15. When placing the cartridge in the outlet housing, make sure the single-hole end is visible. If it is not, remove the cartridge from the housing and install it correctly.
  16. IMPORTANT

    If you do not orient the check valve cartridges correctly, the pump will not operate properly (and may be damaged). Liquid must enter the check valve through the large single hole and exit through the small double holes.

  17. Install the inlet check valve assembly (P/N 045722) on the bottom of the pump head.
  18. Install the outlet check valve assembly (P/N 045721) on the top of the pump head.
  19. Tighten the check valves finger-tight, and then use a wrench to tighten an additional one-quarter to one-half turn.
  20. IMPORTANT

    Overtightening may damage the pump head and check valve housing and crush the check valve seats.

  21. Reconnect the liquid lines.
  22. Close the front door.
  23. Turn on the Dionex Inuvion IC System main power switch.
  24. Prime the pump (see Prime the analytical pump).
  25. When the system is at operating pressure, check for leaks from the check valves. Tighten a check valve a little more only if it leaks.