gas saver time out on Varian 3800

[Bea Matthijs]

As a small flavour house we use a Varian CP-3800 FID with 2 columns (polar and apolair) and an autosampler CP-8400.
As we do not have many experierence using this, I'm coming to this forum for help..

Currently we are looking to minimize our gasses while not using the GC. The tecnhician told us to use the "Gas saver time out" and/or a "sleeping program".

The parameters for the "Gas saver time out" are:
Front and middel EFC:
outlet pressure = ATM
pressure display units = kPa
splitless vent flow (ml/min) = 20
gas saver flow (ml/min) = 5
gas saver timeout (min) 60

sleeping method => all gasses (H2 and air) are on 5ml/min

What we see is that if we do not measure for 3 days that the gasses decrease with +/- 10 bar. Which we find a bit much...

My questions:
1) The gas saver flow is that for ALL the gasses?
2) What is the minimum gas flow that we could use to minimize our usage.
3) Is it necessary to use AND the sleeping method AND the gas saver time out? As if I'm correct, after the sleeping method (which has "time indication" for running...) the machine goes into the gas saver time out anyway.
5) If I would set the splitless vent also to 5, will that decrease the usage?

Thanks!

[Peter Apps]

Before you worry about GC settings you need to make sure that all the connections between your gas cylinders and your GC are leak tight.

Peter