Replacing The Bleed Restrictor Column - Agilent Technologies 6890 Series Service Manual

260 Solvent Vapor Exit Accessory
Replacement procedures
7. Replace the valve/fitting assembly and mount it to the GC oven with the
screw. Cover the open end of the union to avoid contamination and route
the 1/16-inch stainless steel tubing and union into the oven. Repack the
insulation around the tabling. Connect the valve driver cable to the valve
jumper cable or valve driver assembly, as applicable.
Use a new graphite/Vespel ferrule to reconnect the 320 µm transfer line
8.
to the union.
9. Examine the bleed restrictor column. If the column is damaged, replace
it with a new 0.5 m length of 50 m column, installing a new fitting and
ferrule. Be sure to trim 5 to 10 mm off the end of the new column after
installing the new fitting and ferrule.
10. Reattach the solvent waste vent line.
WARNING Because a significant amount of solvent is vented through the SVE valve
assembly, it is important that the bleed restrictor and the solvent vent are
connected to an appropriate laboratory ventilation system.
11. Check for leaks.

Replacing the bleed restrictor column

1. Turn off the GC and unplug the power cord. Allow time for all heated
zones to cool and then turn off supply gases at their sources.
2. Remove the top cover and the right side cover. If necessary, also remove
the pneumatics cover and the electronics carrier cover.
3. Using a wrench, remove the old bleed restrictor column.
Cut a 0.5 m section off of the new 50 µm bleed column for use as the
4.
restrictor.
5. Attach a male fitting and ferrule to the restrictor column, then trim 5 to
10 mm from that end of the column.
Connect the 0.5 m 50 µm bleed restrictor to the SVE valve.
6.
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Inlets
Agilent 6890 Gas Chromatograph Service Manual
Jun 2001