Preventive Maintenance

Split/splitless capillary inlets

6.Turn off flow to the inlet by turning off carrier gas at the flow controller (fully clockwise, turning it only until it bottoms, and then no further).

7.Adjust the back pressure regulator clockwise, an additional 1/4•turn or set the electronic pressure control to 145 kPa (21 psi) and observe column pressure at the gauge for about ten minutes.

If the system is leak•free,pressure will remain between 131 and 138 kPa (19 to 20 psi); if it drops, a leak exists. If there is leakage, turn on the carrier gas supply and

CUse a suitable leak•detectionfluid to check appropriate plumbing connections behind the flow panel and onto the supply itself. Repair or replace fittings and components as necessary.

Caution Leak•detectionfluids often leave contaminating residues: After each application, the area checked should be rinsed with CH3OH (methanol) and allowed to dry.

CCheck the inlet itself at three possible locations:

-The septum.

-The column connection.

-The seal (O•ring)around the insert retainer nut.

Note: The following checks may be done at any time during normal operation without either disconnecting the column or sealing the inlet. Simply pressurize the system and check for overall leak•down.

CCheck for septum leakage by using a bubble flow meter: press its inlet tube onto the top of the inlet needle guide (septum retainer nut). Making sure the tube is flush with the surface of the inlet, check the bubble meter for evidence of leakage. Replace the septum if leakage is observed.

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