To ensure the oxygen probe is functioning properly, follow these detailed steps: First, if you're not certain that the oxygen probe is causing the atmosphere control failure, do not attempt to remove the probe from the furnace. All subsequent operations should be based on the probe being installed or located inside the furnace, at normal operating temperature, and in a reducing atmosphere. 1. Have you corrected the probe's displayed value using a dew point meter (or thin-film carbon determination) method? If so, the issue is not with the oxygen probe. If repeated tests still show incorrect results (error greater than 15%), proceed with the following troubleshooting steps: 2. Check and confirm that the thermocouple's compensation wire and the oxygen probe's signal wire connections are clean and secure, and that they are correctly connected to the instrument's corresponding terminals. 3. Is the control instrument's (the instrument that receives the oxygen probe signal) coefficient set correctly? This coefficient has many aliases: process coefficient, probe coefficient, coefficient, loop coefficient, calibration coefficient, etc. Adjusting this coefficient can reduce or eliminate the deviation between the displayed value and the actual process data acting on the workpiece.