What to do if the signal is not in range and calibration value is very different from last calibration value on Hach Measuring Instruments?
- CcolemankathrynAug 18, 2025
If the signal is not in range and the calibration value is very different from the last calibration value on Hach Measuring Instruments: * Open the sample flow adjustment valve completely. * Ensure the calibration gas doesn't have too much oxygen; use a quality 50 N2 or CO2 bottle. * Check for oxygen leaks between the reference bottle and instrument by increasing the gas flow rate and checking for a partial pressure (mbar) decrease.