AUX 2 heater fault

Aux 2 is typically configured as the transferline heater/sensor.   The simplest thing is to vent the MS, turn off the GC, remove the column, slide the GC away from the MS, and then unplug the transferline heater/sensor connector, plug it back together, then turn the GC back on.  This remakes that connection in case it is something that simple.

If that doesn't fix it, turn off the GC power, unplug this connector, and use a voltmeter to measure the pins on the Mass Spec transferline side. There are two skinny white wires and two thicker wires in diagonal pairs.  The two skinny ones, the Platinum Resistance Thermometer, should measure about 109 ohms at room temperature.  The two thicker wires, the heater, should measure about 17-20 Ohms.  If the heater resistance is much different than that the heater has probably failed and the heater/sensor assembly should be replaced.

(+) Thermal Aux 2 - No Sensor for Heater - Forum - GC/MS - Agilent Community

Thanks. We got it replaced and configured, all is good now.

I wanted to add this note for anyone else ending up here after searching for Aux2 heater fault.

Our lab had a power outage recently and upon restarting the GCMS I had the same issue as garyb007. The resistance check suggested by paulsalverda found no issues in the heater or thermometer. After some troubleshooting, I checked the GC Configuration (Config button on GC - scroll down to Aux Temp 2) and found that it had changed configuration type from MSD Transfer line to Unknown. I re-set it to MSD Transfer Line, rebooted the GC, and all was functional again. This saved a service call or ordering a unnecessary replacement part (that would not have worked anyway).

Thank you for sharing this!