Chapter 10
Ensuring Tightness
Leak Test the Lines from the Gas Source to the GC
188
Maintenance and Troubleshooting Manual
OPERATING SEQUENCE
Leak Test the Lines from the Gas Source to the GC
1. Switch off the gas chromatograph power supply.
2. Turn on all gas supply lines to the GC, setting the input pressure to 420 kPa
(60 psi). Allow the gas lines to pressurize for several seconds.
3. Turn off the input gas source. The pressure value should not change more than
5% in 10 minutes. If the value drops down immediately, one or more leaks are
present. In this case:
4. Check the connections with the Thermo Scientific GLD Pro leak detector, or
equivalent handheld electronic leak detector, to find possible leaks.
Multiple systems
If more than a system is attached to the same gas source, you will need to isolate
each GC system.
1. Install a cut-off valve
and pressure gauge
with an 1/8 inch input tee in the gas
line leading to the GC that you are leak testing, as shown in Figure 10-3. Be
sure the pressure gauge is connected in line between the on/off valve and the
GC.
2. Turn on the gas supply and allow the system to pressurize.
3. Turn off the input gas source. The pressure value should not change more than
5% in 10 minutes. If the value drops down immediately, one or more leaks are
present in the plumbing from the cut-off valve to the GC. In this case:
4. Check the connections of the line you are testing with the leak detector to find
the leaks.
