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Thermo Fisher Scientific

Gas Lines


Regular leak check of each gas line from the gas supply in the laboratory to the instrument is needed.


Q Exactive GC


Perform a Leak Check
  1. After closing all valves in the instrument, monitor the manometer of the gas regulator for some minutes.
  2. If the pressure falls significantly (for example, the nitrogen pressure falls by more than 10 psi / 690 mbar within two minutes), you should search for leaks in the gas line. This nitrogen pressure test cannot be performed when the instrument is powered off because the nitrogen is freely flowing through the vent valve.
  3. Search for leaks in the gas line, for example, by using a conventional thermal conductivity-based leak detector, such as is widely used to check leaks in gas chromatography equipment.
  4. If you detect a leak (which is usually at a connection), verify the tightness of the connection. In case of doubt, replace it. 5. When you cannot find a leak in the gas line, we recommend calling a Thermo Fisher Scientific field service engineer to check for gas leaks within the instrument.

NOTE: These leak detectors will not detect nitrogen levels.

Additional Information
  • When the Q Exactive GC is in the On or Standby state, nitrogen is consumed at approximately 6 mL/min.
  • The system should be placed in the Off state for pressure checks.


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