Chromatography Forum

Hello,

I am a graduate student working with a FID-GC (GC series 6890). I am working on an experiment that uses tenax-packed sorption tubes through thermal desorption to determine the concentration in a series of chambers. Last week I began seeing an error on the unity screen that says "valve not heating." When I press the abort button, nothing happens. The autosampler tray stays inside the thermal desorption area and won't come out. The extent of my ability to trouble shoot is to turn everything off and systematically turn it back on, this has not helped. Has anyone encountered this before?

Any help would be GREATLY appreciated!

Sounds like the heated transfer valve in the Unity is playing up. If the software's crashed it is possible to manually eject the tubes and tray but I can't remember how. My best advice is to email or call Markes as even though we don't have a maintenance contract (or maybe they have forgotten it ran out years ago) their tech support is very quick and more helpful than just about every other instrument vendor added together. If you're really stuck and they can't or won't help I'll try to remember how to eject the tray and tube, I presume you have the Ultra 50/50 autosampler, the big tower?

IS your system a unity 2? if so can I buy or barter for a copy of the software. Our computer crashed and I cant find the disk.