Thermo GC oven - will not cool to initial temperature

[fgrun2]

We have a Thermo Trace 1300 GC with an ISQ QD mass spectrometer running Chromeleon 7.

The GC is set up in Gemini mode (i.e. dual injectors and columns for separate FID and MS samples). The instrument has stopped working because it is stuck trying to reach the initial oven temperature (40 oC). It will cool but stays at an elevated temperature (60 oC).

After opening the door, I can get the temperature to drop down down to 30 oC, so the sensor appears to be working. But after closing the door, the oven rapidly returns the temperature back to a stable 60 oC, which prevents the sample queue and injector sequence from starting. The status displays "Waiting for oven". After 15 minutes the sequence queue will time out.

However, if I run a gradient method with an elevated initial temperature (50 oC), the sequence will start and run properly, but it will not return all the way down past 60 oC.

I have checked all the methods to ensure there are no aberrant method parameters present. The software has been reset and instrument powered on/off several times without resolving the issue.

Any ideas ?

[Consumer Products Guy]

I have zero experience with Thermo units but with our old Agilent units, we did have occasional symptoms that were similar. These were typically traced by flaps in the rear not closing completely by their electric motor; once the metal flap actually broke off and I riveted it back on to fix.

[Jiac91]

hello, good afternoon. Did you find a solution to your problem? I have the same computer and am having a similar problem. In my situation, during the analysis, the temperatures of the oven, injector and detector go according to the method and suddenly they begin to drop, the analysis pauses, an error message appears and the equipment begins to turn a light on and off in "ready". " in orange and a sound starts. It doesn't allow me to continue analyzing until I restart gc. I'm waiting for a response, sorry for the inconvenience.
thank you so much

[GCMSeng]

I've worked on Thermo GCMS systems for quite a while now. Consumer Products Guy is probably right.

The flapper motor (that's what Thermo used to call it) or stepper motor that controls the flaps at the back of the oven has probably gone bad and the oven exhaust flaps are either stuck in place or have limited movement.

A quick test to verify this is to manually set the oven temperature to a much higher temperature (like 200 degrees C or higher) and, after allowing the GC to try to heat up for a small bit, quickly open the oven door and look back to the back-bottom of the GC oven...If you are fast enough about it, you should see the oven exhaust flaps react to the door being opened (if working properly) by moving from a fully-closed position (flap pointed straight upward) to an open position (flap pointed backward). If they are stuck open, stuck closed, stuck in a position, this should help you to see that.