Air+ H2 OFF after run, instantly ON afterwards. Why??

[alba]

Dear all,

I'm using an FID and I cannot understand why my air and hydrogen flow sets to "OFF" just at the end of the run, then instantly go to the set flow.

I've been using a GC before but with this new one I'm having this problem. I feel that it is not a problem with pressures (because the flow setpoint goes to OFF, doesn't decrease) but with something set on the method/sequence.

Any idea?

Thanks in advance,

[sepscientologist]

We will have to know your instrument. If it Agilent I would check your lit offset value.

[alba]

The instrument is Agilent 6890.
Thanks.

[alba]

Dear all,

I managed to avoid the problem I described previously. It was just a problem with the movement of a valve. It was being switched too soon.

Thanks,