Hello everyone,

I'm running into problems running our multiflow with soil headspace samples.
After about 10-15 samples the He flow through the sample loop drops
drastically (from 20ml/min to 7ml/min), and the column head pressure
increases from 17psi to >30psi. Thinking it may be a water issue, I plumbed
in an additional water trap after the nafion dryer to pick up any residual
water, and swapped in a new column - no improvement. Also tried swapping in
a shorter sample loop in the event there was a blockage of some sort. 

Has anyone experienced issues with the valco 6-way vale not rotating
completely, resulting in the pressure increase and flow reduction that I am
describing? The 6-way appears to be rotating completely....

Any help would be appreciated.
Matt