Chromatography Forum

When I was doing the experiment. Suddenly, The thermal system had a fault. Then, the warning alarm rang. All the temperature was off. So I waited for everything cooled down. Shutdown the GC system completely. After that, I restarted the GC. I increased the FID’s temperature to 200C. Everything was good. As I increasing the temperature to 400C. FID’s temperature cannot stable at 400C. There was much oscillation here. Then, the front panel of FID showed “ Temp not installed”. Is that mean some units were broken down? Do I need to replace some sensors?

There was a similar problem is posted in the forum. I don't whether the problem was solved. Here I put the link. Thank you all the people who can reply to this post

https://chromforum.org/viewtopic.php?t=25467

The GC is Agilent 6890N

First to check is that the heater and sensor connection to the board are ok. Try unplugging and then plugging everything back to see if this helps. If not, check continuity between all connection points. If there is an issue with continuity in the loom, it may throw an error.

Also, why is the FID temp 400C? Isn't 300C more optimal for FID operation (on Agilent products anyway)?

Its probably the sensor going bad. If you can, pull the inlet out and measure the resistance. They're normally fairly low - around 100 ish ohms (the temp sensors tend to be similar values from what I've seen). If it measures around zero ohms or infinite, the sensor needs replacing. You'll probably have to buy the whole assembly - the block and heater element unless you can find a sensor of the right type and splice it into molex connector.