Typical HiVac pressure for 5977B?

[morktech1]

Hello all,

I'm curious what the group sees as typical and good pressure on HiVac gauge on the 5977B. We realize it depends on column flow and there is a table in the manual.

Our system is a Headspace GC/MS (Agilent 8697/8860/5977B). When running 1.2 mL/min through the column we are reading 1.03 x 10^-5 after a couple days of pump down time. Instrument is 3 years old, light usage.

Is this typical? Curious what you all see. The manual says we should be within 30% of 7.33 x 10^-6 at this flow rate. We are just slightly higher than that (40% higher).

Thanks!

[cjm]

More importantly, what does your air/water check look like? If this is good, I would expect a slightly better vacuum, say 5 to 8 x10e^-05. How old is the rough pump oil?