High/Low Measured Values - ABB Aztec 600 Color Manual

Aztec 600 aluminium, ammonia, color, iron, manganese, phosphate
Single- and multi-stream colorimetric analyzers
B.4.2 High/Low Measured Values
Check/Symptom
Check analyzer settings
Check analyzer
calibration
Check sample points
and external method
Check filter
82
Action
Ensure that the analyzer is set up and operating within its specification.
1. Check the units the analyzer is displaying are the same as the comparison method.
2. Check the analyzer is operating within its measuring range.
3. Check the analyzer is operating within its ambient operating temperature and humidity.
4. Check that the analyzer is not operating erratically.
Ensure the analyzer is calibrating correctly:
1. Check the standard concentration matches the analyzer setting.
2. Check the optical density of the low calibration solution is within the expected range –
recalibrate if necessary.
3. Check the optical density of the high calibration solution is within the expected range –
recalibrate if necessary.
When comparing analyzer results to laboratory or portable analysis techniques it is important to
ensure that the samples analyzed are the same and that the analysis methods are comparable.
1. Check that the sample taken for external analysis is the same sample the analyzer is measuring
by collecting the sample from the overflow from the side sample pot.
2. Check that samples taken are analyzed in a timely manner.
3. Check that the collected sample does not undergo additional treatment prior to analysis, such
as further filtering, settling and acid digestion.
4. Check that the comparative analysis method is not measuring the 'Total' amount of the
parameter in the sample.
For example, laboratory methods such as ICP analysis may read higher than online analysis
methods on raw waters.
5. If a portable test kit or bench-top instrument is used for comparison, ensure that this is
measuring accurately.
Check:
a. reagents used are in date
b. the instrument has been calibrated
c. performance on known standards
d. the analyzer is operating within its working range and accuracy
If a filter is used prior to the analyzer, it is possible that some important parameters are being filtering
out before analysis takes place:
1. Analyze a sample taken before and after the filter to check if the concentration changes
significantly.
Appendix B – Troubleshooting
IM/AZT6CR–EN Rev. R