Simple Checks; Unstable Or Erratic Readings - ABB Aztec 600 User Manual

Aztec 600 aluminium, ammonia, color, iron, manganese, phosphate
Single- and multi-stream colorimetric analyzers
B.4 Simple Checks
B.4.1 Unstable or Erratic Readings
There are a number of possible causes of unstable or erratic readings. Follow the checks outlined below to determine cause. If these
actions do not resolve the issue, run the analyzer on a solution of known concentration to establish if the analyzer is unstable.
Check
Check operating range
of analyzer
Visual check for air
bubbles
Check for restrictions
in analyzer tubing
80
Action
The analyzer may appear to be giving erratic results, when actually the error is due to the scaling of the
chart or the units being displayed.
1. Check the analyzer is measuring within its range – see Section 14, page 74.
2. Check if the measuring range is at a similar level to the dilution set point – change the dilution
amount if required – see Appendix A.3, page 78.
3. Check which units the analyzer is using to display the results.
Check for air bubbles in the analyzer tubing. This can indicate a loose barbed connector, incorrectly
attached tubing or a faulty valve.
1. From the sample line(s):
a. Check the sample barbed connector on the valve manifold – tighten if necessary.
b. Ensure that sample tubing is fitted correctly to the barbed connectors.
c. Check the sample solenoid valve(s) and ensure that the valve face gasket is located correctly
– see Section 13.3.4, page 64.
2. From the reagent line(s):
a. Check the reagent barbed connector on the valve manifold – tighten if necessary.
b. Check the reagent barbed connector on the top of the level sensor – tighten if necessary.
c. Ensure that reagent tubing is fitted correctly to the barbed connectors.
d. Check the reagent solenoid valve(s) and ensure that the valve face gasket is located correctly
– see Section 13.3.4, page 64.
3. Drop back on all reagent lines:
a. Check the barbed connector in the centre of the valve manifold – tighten if necessary.
b. Check the barbed connector located at the base of the head assembly – tighten if necessary.
c. Ensure that the tubing connecting the valve manifold to the head assembly is fitted correctly
to the barbed connectors.
d. Check that the piston seal is not leaking. Replace if necessary – see Section 13.3.6, page 70.
Sharp bends or kinks in the tubing or compressed tubing result in restricted flow that can cause erratic
or incorrect readings. Trace each of the reagent/sample lines from the valve manifold and ensure that
the liquid flow is not restricted.
Check for:
1. Cable ties that have been tightened around the tubing – remove if necessary.
2. Check that tubing is not trapped or squashed.
3. Check that there are no kinks in the tubing – replace tubing.
4. Check integral filter located at the base of the reagent level sensor has not become blocked.
5. Ensure analyzer waste is free-flowing to an open drain (not submerged).
Appendix B – Troubleshooting
IM/AZT6CR–EN Rev. J