We're looking at a BZHE150 Broad absorber that won't do any work. It continually trips on a "HTG low level (Zone A)" alarm and goes into decrystallization. It appears to have excessive non-condensables (bubble rate much higher than spec) which we have started to remove. Unfortunately we have little in the way of usefully information, manuals etc for this machine. We believe the vacuum should be between 5 to 6mm of Hg: where and when (running or stopped) do we measure this and is a digital vacustat suitable?