Discussion Category: GC Systems
FID won't ignite
I am having problems with the FID igniting. The detector tries to ignite, but it continues to make a popping sounds, and as soon as it has a flame it immediately goes out. I have it set to retry ignition automatically, and it will continually retry-bu8t never catches. This is a new issue, and it wasn't doing this prior to repair yesterday. I have set the instrument to it's default flow parameters (30 MakeUp, 40H2, and 400Air). I have a megabore column on the system and column flow will adjust automatically to make the linear velocity 39.5cm/sec which is what it was previously running at. Please help if you have advice!
Thanks!
Reply byRahekm,
Sometimes blowing across the top of the FID while it is attempting to ignite will allow it to do so. If it is problematic in that it continually has problems, I have found that many times it is the result of the jet not being snugged down enough. Do NOT overtighten it but do make sure that it is tightened appropriately.
Dan
Dan Ste.Marie
RJ2 Instrument Services
Erie, PA
www.rj2.biz
Reply byRahekm is correct. Sometimes ignitors get old and do not provide enough spark to ignite the flame. Blowing 'gently' over the FID opening can help ignite the detector.
Try a butane lighter, prefereably a long one used for outdoor grills. If the flame has been out for a while, use the lighter flame around the FID castle housing to help warm and desiccate the housing area. Be careful to keep the lighter flame away from any electronics and wiring. Then, hold the lighter flame over the FID opening as the system is trying to ignite the flame. Sometimes holding the lighter flame slightly above (away) from the opening helps, too.
Look for leaks at all junctions starting at all gas regulators connected to the GC and ending at the detector column inlet. Moisture from slight leaks of ambient air seeping into the system can cause the same symptom. To cure a GC system of this problem, I had to use a leak detector on all gas lines to track down two minor leaks that, apparently, were enough to allow our Midwest high humidity air into the system.
Hope this helps. Let us know the final diagnosis and cure.