We are having an issue with our 7890B GC back inlet. The inlet temperature and flow were both set to "OFF," but the back inlet kept heating up while were were trying to run the front inlet (in GC-FID mode). This resulted in a thermal shutdown, which turned off all of the heated zones. In the back inlet configuration, I set the IGNORE READY to TRUE, and restarted the GC. However, we continued to get the same error. We have now unplugged the heater to the back inlet, which is letting us run, but obviously has not fixed our problem. I cannot find a part number or instructions to replace the back inlet heater. Can anyone point me towards this information? Or towards an alternate solution?