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Table 7.1 Calibration failure: possible causes and recommendations
Possible causes for calibration
failure
Recommendations
The sensor's span reserve percentage is
less than 50%.
The sensor is due for replacement.
The gas cylinder did not contain the
calibration gas in the concentration needed.
Repeat the calibration with a suitable gas cylinder.
When all sensors fail, this may indicate the
calibration gas did not reach the sensors.
Check for the following.
Ensure the calibration cup is compatible with the instrument.
Ensure the calibration cup is correctly and securely placed on the
instrument.
Check the tubing for splits, blockages, or damage.
Ensure the tubing is secured to the calibration cup and the cylinder's
regulator.
Ensure the cylinder is not empty and contains the required gas
concentrations.
Be sure the cylinder is turned on when the apply-gas screen displays and
remains on until the calibration is completed.
Repeat the calibration.