-
- Posts: 165
- Joined: Sun Oct 04, 2009 6:18 pm
I have an issue with an old 6890N with two FIDs installed. We've always run 400 mL/min air to 40 mL/min hydrogen with no issues. Recently the actual reading on the back detector continually fluctuates between 398 and 402, the GC saying "not ready" due to back detector air flow. Baseline/signal look good while it remains lit. However, every so often, it will just turn itself off and shut down air and hydrogen flow. Not sure what would cause this fluctuation. Software doesn't allow to ignore the setpoint of 400 mL/min. I have verified there is more than adequate air supply in to the system, as I can turn the air up to 500 mL/min and it'll reach the setpoint. Any ideas, thoughts, tricks would be greatly appreciated.
Christian