Maintaining the Instrument
Leak Testing a G1290/G1883 to GC Interface
111
WARNING Turning the valve may not completely shut off flow, depending on the setting of
the knob on the stem. Also excessive pressure on the stem can damage the
flow controller if the knob is set to allow full travel.
3. Using MANUAL OPERATION, switch the sample valve to 0 or OFF. (See
“MANUAL OPERATION” on page 48 for details.)
4. Monitor the pressure on the front panel display—it should equilibrate at
some pressure close to the line pressure and then hold. It should drop less
than 2 psi in 5 minutes. If the pressure drop is much greater, there is a leak.
5. Using MANUAL OPERATION, switch the sample valve to 1 or ON to
include the sample loop.
6. Repeat steps 2–5.
7. After the test, remove the septum or plug. The flow path should
instantaneously de-pressurize. If it does not, there may be a restriction.
8. Using MANUAL OPERATION, switch the sample valve to 0 or OFF to reset
the sample loop.
Vial Pressurization Flowpath
1. Prepare a new, empty 20 ml headspace vial. Make sure that it is capped
properly. See “Sample Preparation” on page 56.
2. Manually install the headspace vial in the oven slot under the headspace
probe.
3. Using MANUAL OPERATION, load the vial onto the probe and make sure
the Pressurize Valve is “ON” and the Vent Valve is “OFF”.
4. Pressurize the vial to 20 psi by adjusting the pressurize regulator.
5. Wait at least 1 minute to allow the system to equilibrate, then shut off the
pressurize regulator (full CCW).
6. Monitor the pressure on the front panel display. It should equilibrate at
some pressure lower than 20 psi and then hold, dropping less than 5 psi in
10 minutes. If the pressure drop is much greater, there is a leak.
7. Using MANUAL OPERATION switch the sample valve and repeat steps
2–6.
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