SCD Output

I run an agilent 8355 SCD. I had it set up for a 5 minute post run (allows for the TDU lines to thaw in-between samples when I run samples overnight) and I've noticed lately that the rough vac reading drops from 8.07+1 to 7.16+1 during the post run and that causes my scd output to spike slightly. Anyone have an idea as to why the vac drops during my post run and how to prevent it from doing that?

Was this helpful?