Waters Xevo TQD Operator's, Overview And Maintenance Manual page 214

8. Route the open end of the exhaust tubing to a suitable exhaust vent.
9. Check the oil level in the pump (see "Checking the roughing pump oil
level" on
page 4-25).
10. Make the electrical connections to the roughing pump (see
B-6 External Connections
The instrument requires two separate exhaust systems:
Caution:
one for nitrogen, the other for the roughing pump. Vent them to
atmosphere through separate exhaust lines. Oil mist can severely
damage the instrument if the nitrogen exhaust line connects with
the roughing pump exhaust line. Your warranty does not cover
damage caused by routing exhaust lines incorrectly.
To ensure correct operation of the roughing pump, do not
Caution:
operate the pump with the oil level at less than 30% of the MAX
level.
page 4-25, and, if needed, "Adding oil to the roughing pump" on
page B-7).