Chromatography Forum

Hi, very new to GC FID and the Trace gc Ultra device. On powering it up it gives the hardware shutdown screen because it thinks it is at 632oC. Does anyone know how to replace the oven temperature sensor (assuming that’s the problem). Apologies for such a basic question, Jim

First , you may check the sensor if it is really faulty and needs replacement.
You need an ohmmeter to check it.

Unplug the instrument ,remove the right hand side panel of the GC , there is a hex screw at the back side of the panel , loosen it , slide the panel to the back , tilt and remove.

You will see multiple sensor connectors on the electronic board , locate the '' oven '' sensor connector , it has two wires , check the resistance between the wires , it must be around 105 -110 ohms when the oven is cold.

If it is open circuit ( no resistance reading ) or short ( zero ohm reading ) , it is faulty.

For replacement of the sensor , you may google '' Thermo Trace GC service manual '' and you will get the manual , there is full explanation of sensor change procedure on the manual.

Good Luck !

Hi Uzman,
I really appreciate the quick response to my question. I have the manual and check the resistance of it tomorrow and report back. Fingers crossed that is all that is wrong. Many thanks, Jim

Hi Uzman,
I really appreciate the quick response to my question. I have the manual and check the resistance of it tomorrow and report back. Fingers crossed that is all that is wrong. Many thanks, Jim

I checked the resistance of the oven temperature sensor as you suggested and it read 103.6 ohms. On reassembly it now seems to be starting up robustly and reading correctly without error. Looks like it might have been a bit of a dry contact and the investigation with confirmation that the sensor was not faulty sorted the issue. Very many thanks for your help - greatly appreciated. Jim

You wellcome Jim , good to hear that it worked out !

Hi all,

Glad to see this issue was resolved! It’s always good when a careful check clears things up without needing a part replacement. Uzman’s diagnostic steps are spot-on and likely to help others facing similar GC startup errors.

For those who may run into comparable symptoms with Trace GC systems (or are just looking for more background on temperature sensor faults), here’s a short article that outlines key troubleshooting tips and common failure points:

GC Oven Temperature Sensors: Diagnosing and Troubleshooting Malfunctions for Consistent Performance

I hope it’s useful for anyone revisiting this thread down the line.

Best,
Shiama

Great article - many thanks.