7890B GC front FID detector does not ignite

[Fouadm]

Hi
Many thanks to you in advance.

I have a problem with the front FID which do not go on as the igniting trials have not succeeded.
I have a doubt about the front inlet configuration.

Any suggestions are highly appreciated.

[dblux_]

Hi
Many thanks to you in advance.

I have a problem with the front FID which do not go on as the igniting trials have not succeeded.
I have a doubt about the front inlet configuration.

Any suggestions are highly appreciated.

1) Does your igniter glow ?
2) Check if hydrogen and air go to FID. Don't rely on setting values. You must prove by flowmeter or by other means. This will check if FID nozzle is not clogged as well.
3) Set stoichiometric flows of gases. Reduce makeup and column flow.
4) Blow a little when igniting.
It must ignite.
BTW - let hydrogen flow as long as air is blown from the line.

[Consumer Products Guy]

Sometimes, on certain of our GC systems, we would blow gently into the detector as it was trying to ignite.

[dblux_]

Sometimes, on certain of our GC systems, we would blow gently into the detector as it was trying to ignite.

That was point 4).
Needless to say FID should have at least 150 degC to ignite - this will be point 5).

[dblux_]

Let me add point 6) - Lit offset for FID shouldn't be set too high.

[AICMM]

Very important point. Blow gently ACROSS the top of the detector, never down into it. Every once in a while they spit fire and you do not want youR head above that. If it makes you nervous thinking about it, you can also use an old fashioned red pipette bulb (the big ones for volumetric pipettes) and puff away at the top of the FID to help it light.

Best regards,

aicmm

[James_Ball]

Hi
Many thanks to you in advance.

I have a problem with the front FID which do not go on as the igniting trials have not succeeded.
I have a doubt about the front inlet configuration.

Any suggestions are highly appreciated.

What would be your doubt about the front inlet configuration? Just wondering how that might affect the detector end.

If the glow plug is going bad, you can try to light it the old fashioned way with a welding torch striker or butane lighter held above the outlet, should get the pop sound when it lights.

Also you can hold a beaker just above the outlet and see if condensation forms, if it does then it is lit but the electronics are not reading signal.

[Peter Apps]

Is the column connected to the detector ?

What flows do you have set for air and hydrogen, and are you using make-up gas ? Have you verieid the gas flows with an independent flow meter ?

Have you checked the position of the tip of the column relative to the FID jet - the operator's manual will tell you how far past the detector nut to insert the column.

Peter

[Podor]

Let me add point 6) - Lit offset for FID shouldn't be set too high.

Good point, one time our 7980 wasn't staying lit because the offset was 2 pA, but our baseline was below that. Sometimes using high purity gases with appropriate filters results in too high of a purity and the GC thinks the FID isn't lit.

If you monitor the baseline before the detector shuts down and determine this is the cause, the lit offset is controlled on the GC's interface. There is no way to change it in ChemStation.

[Consumer Products Guy]

the lit offset is controlled on the GC's interface. There is no way to change it in ChemStation.

One could with the older Chemstations; don't know about the newer versions.