Plunger Assembly Maintenance

Plunger Assembly

The plunger assembly consists of a Teflon piston attached to a piston rod. The outer rim of the piston is expanded outward with an embedded quad ring.

The piston is resistant to wear and provides sealing for prolonged usage if handled and maintained properly. It is recommended to clean the sealing area daily using a wipe moistened with isopropyl alcohol. Enure the seal is dry before using the plunger again.

Check Plunger Seal

When a leakage develops, it is typically caused by the piston having lost some of its expanded condition due to a characteristic of Teflon undergoing cold flow — as opposed to wear. The piston is easily restored to full operation when the cause is not wear.

Wipe or brush the piston free of adhering particles. Use a round-bottom object, such as the handle of the brush supplied with the analyzer, press down on the quad ring, and move the object around the piston circumference, forcing the piston rim outward.

Replace Plunger Piston

It is recommended to replace the piston and the quad ring at the same time.

  1. Unscrew the piston rod from the piston.
  2. The quad ring is preloaded in the groove on the front of the piston. If it has become dislodged, insert the quad ring into the groove on the front face of the piston.
  3. Screw the piston rod into the back face.
  4. Tighten the plunger assembly firmly without using excessive force.
  5. Test the tightness of the piston:
  1. Place the plunger in an empty chamber.
  2. Holding the plunger still, rotate the chamber around the plunger in a direction that would tend to unscrew the piston. If the motion of the chamber begins to unscrew the plunger assembly, it needs to be tightened further.

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