7890 GC very slow to be ready

hello, we have a 7890 GC with 5975C MS and Frontier 3030 pyrolyzer. Recently the vacuum gauge didn't work (repair pending, not reading anything), although it still could be used. After replacement of a broken split vent line and everything was put back together and leak checked, the inlet temperature appeared to be very slow to heat up than before and we had to put the insulation cup on. The inlet before didnt have any issue heating up even without an insulation cup because Frontier selective sampler was installed. Even when the inlet temperature reached the set one (300C), there was a star blinking next to the actual temp and the system was not ready and the sequence could not be run due to the pyrolyzer needed to wait for GC to be ready to kick off. If I turned off the GC and restarted, the issue appeared to be fixed temporarily. What could cause this issue, hardware, software, communication? Thank you. 

  • The insulation cup is smart to have on all the time as it helps keep the bottom of the inlet hotter as it reduces the temperature differential between the middle and the bottom.

    It still should heat up and come ready normally.  On the GC keyboard, press the blue Service Mode button. Select - Diagnostics, Thermal PID control, Front (or Back) inlet temperature, and look at the Duty Cycle.  What is it?   Even at 300°C, when it has come all the way to temperature and stabilized, the duty cycle should not be 100%.

    To find out what is causing a 7890 to be Not Ready, press the Status button and the GC will tell you what is not ready.

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