Excessive pressure fluctuations (more than 3% difference from one pressure reading to the next) indicate that the pump is out of prime.

Possible cause

Solution

Empty eluent bottle and/or no eluent connected

Fill the bottle. Verify that all connections are secure and then tighten as required.

Eluent improperly or insufficiently degassed

Procedure

  1. If the vacuum degas assembly is not installed: Manually degas the eluent (see Vacuum Degas Assembly Does Not Run).
  2. If the vacuum degas assembly is installed: Check the Command window in Chromeleon CDS. If a problem is reported. the vacuum degas assembly may need to be replaced. Contact Thermo Fisher Scientific Technical Support for assistance.

End-line filter is dirty or clogged

New end-line filters (P/N 045987) are pure white.

Procedure

  1. If the system is in continuous operation, change the end-line filter weekly or whenever it becomes discolored (usually an amber or orange color).
  2. Replace the filter more often if bacterial buildup is visible or if the eluent does not contain solvent.

  3. IMPORTANT

    It is especially important to replace end-line filters regularly when using aqueous eluents, which may contaminate the filter with bacteria or algae. The bacterial buildup may not be visible.

Blockages in inlet tubing

Check for kinked or clogged tubing, which may be causing the pump to be “starved” for eluent. If necessary, replace the tubing and fittings (see Replace tubing and fittings).

Dirty pump check valve

Clean or replace the pump check valve (see Replace the pump check valves).

Liquid leaks at junction between pump head and pump casing

Procedure

  1. Using the open-end wrench (P/N 014605) provided in the Dionex Inuvion IC System Ship Kit (P/N 057905), tighten the two nuts that attach the pump head to the pump housing. Tighten the nuts evenly (12 in-lb torque).
  2. If the leak persists, replace the piston seal (see Remove and replace the pistons, analytical pump seals, and O-rings).

Liquid leaks from seal wash port

Replace the piston seal (see Remove and replace the pistons, analytical pump seals, and O-rings).

Scratched pump piston

Inspect the pump pistons. If a piston is scratched, replace it (see Remove and replace the pistons, analytical pump seals, and O-rings).