Chromatography Forum

I'm having a problem with my Agilent 6890. I'm trying the light the FID. With the gases flowing (H2, Air, He), the instrument goes through the sequence to light the flame. The flame lights (I lear a pop and can see condensation on a mirror), but nothing registers on the electrometer. It essentially stays at zero. Shortly thereafter, I get a Flame Out Error #214. When I put a screwdriver into the collector, the electrometer pegs out so it appears to be working. Any ideas why the electrometer doesn't recognize the flame as being lit?

I'm having a problem with my Agilent 6890. I'm trying the light the FID. With the gases flowing (H2, Air, He), the instrument goes through the sequence to light the flame. The flame lights (I lear a pop and can see condensation on a mirror), but nothing registers on the electrometer. It essentially stays at zero. Shortly thereafter, I get a Flame Out Error #214. When I put a screwdriver into the collector, the electrometer pegs out so it appears to be working. Any ideas why the electrometer doesn't recognize the flame as being lit?

Does the signal stay at 0 or slightly above after it is lit?

The instrument only uses the signal as an indicator of the flame being lit. There is a setting on how much signal it takes to consider the flame lit but I dont remember exactly which one it is, but sometimes if there is extremely low signal at baseline that setting has to be lowered for the instrument to recognize the flame is still lit.

Have you cleaned the FID or adjusted the gas flows a little to try to raise the signal? That might also help it stay lit.

Look in the FID detector conditions window, something like Lit offset (or something offset), and set it to a lower number like 0.5, the default is 2.0.

Look in the FID detector conditions window, something like Lit offset (or something offset), and set it to a lower number like 0.5, the default is 2.0.

From GC keyboard:
Config > Front (Back) detector > Lit offset

PS - John, putting a screwdriver into FID collector doesn't seem to be right diagnostic procedure

+1 on the advice to see what the signal is and then adjust the Lit Offset. Done it many times. I had a service guy tell me to take a syringe and fill it with acetone, then empty it completely and stick it down in the flame to see a peak (needle flash). Sounded rather kludgy to me.

Also check that the little spring from the detector electronics actually reaches and touches the edge of the stack disk. Mine shrank over time and I had to stretch it out so it made proper contact. A think spatula blade is good for getting it aligned on the edge properly.