Unprompted venting of MS roughing pumps

[hlflemng]

Over the past couple of weeks, with increasing frequency, the roughing pumps have vented on their own. Usually this happens overnight when the instrument is not being used but it has also happened during a sample list run. The pumps vent and the vacuum is lost. We have no problem pumping down and maintaining the vacuum. Also the turbo speeds seem to be fine. Anyone ever have this problem or have any troubleshooting tips? Thanks.

Heather

[MSCHemist]

Do you mean the foreline pressure gets too high and the MSD shuts down the hi-vac as well? It could be either the rough pump is dying perhaps locking up or something or there is a major leak say at the side plate o-ring.

[Don_Hilton]

Have the rough pumps shut off or have they actually vented air back into the system? I do not see here what kind of instrument this is. Do you restart the pumps by software command or turn a power switch off and then back on?

A bit more information would help, particulary, the type of instrument, the state of the whole instruent, and the steps you take to retstart it.