Agilent Technologies 7890A Troubleshooting Manual page 19

FID Does Not Ignite
Troubleshooting
• Verify that the Lit Offset is < 2.0 pA.
• Check that the FID ignitor glows during ignition sequence.
(See To Verify FID Ignitor Function During Ignition
Sequence.)
• Check for a plugged or partially plugged jet.
• Check the FID flow rates. The hydrogen:air ratio greatly
impacts ignition. Nonoptimal flow settings can prevent
flame ignition. (See To Measure a Detector Flow.)
• There could be a large leak in the system if the flame still
will not light. Large leaks result in measured flow rates
being different from actual flow rates, causing nonideal
ignition conditions. Thoroughly leak check the whole
system, especially the column fitting at the FID.
• Check the column flow rate.
• Check for leaks at the FID column fitting.
• Ensure that the FID temperature is high enough for
ignition (>150 °C).
ALS and Detector Symptoms
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