Cleaning or Replacing Booster Pump Piston

Tools required

Qty.		p/n	Description
1			Tools for removing the vapor shield (see ) and pump head (see )
1			A 9/64” hex-drive wrench

Parts required

Qty.		p/n	Description
1		G4301-20101	Piston SFC Booster

NOTE

In most cases, this procedure will be used only to replace a broken piston. Pumping CO₂ does not tend to leave deposits on the piston. Development of such deposits warrants examination of the CO₂ supply system and corrects the source of the deposited materials. Release of extraneous materials into the CO₂ supply system may cause contamination of the Agilent 1260 Infinity III SFC System.

Remove the Vapor Shield.
Remove the pump head.
Clean the pump head.
CAUTION
Take care not to break coolant tubes
- Use care removing the chiller assembly from the mounting posts. The assembly is connected to a circulation pump behind the drawer panel. Do not pull the flow lines hard as this may loosen or crimp the tubes and cause the chiller to lose efficiency or cause leaks in the secondary cooler system.
With a gentle rocking motion, loosen the chiller plate assembly and carefully slide it forward off the pump head mounting posts. Carefully twist the assembly out of the way.
Use the 9/64” hex wrench to unscrew the two cap screws attaching the spacer and very carefully remove the spacer by pulling straight back. This fully exposes the piston and retaining ring.
Remove the retaining ring by prying it out with a small blunt instrument or tweezers at the slot provided.
Grasp the metal base of the piston assembly so that you avoid exerting any side load on the sapphire rod, and remove the piston from the slot in the carrier by sliding it up.
Grasp the metal base of the replacement piston assembly, and insert it into the slot in the piston carrier until it bottoms in the slot.
Replace the retaining ring and spacer. Reattach the spacer mounting screws. If properly positioned, the spacer should be pressed into the foam wall seal.
Gently slide the chiller back onto the pump mounting posts and firmly press it onto the spacer. If properly positioned, the chiller heat exchanger should now be pressed into the foam wall seal.
Replace the piston seal
Replace the pump head
Replace the vapor shield

21-Jun-2025