Page 81 - PBL71 OI/AXM630-EN AZTEC 600 SS (WIRO)

Aztec 600 ISE ammonia and fluoride
Single-stream ion-selective analyzers
Appendix B – Troubleshooting
B.1 Analyzer Malfunction
In the majority of cases, problems experienced are associated with the probe so check this first – see Appendix B.3. If the problem remains, check the chemistry (see Appendix B.2) and the liquid handling section as described below. Other faults, their possible causes and suggested remedies are shown in Table B.1 on page 78.
Check mechanical components that are involved with the liquid handling systematically. For example, check pump and valves for correct operation and tubing and tubing connections for leaks or blockages that could change the chemical conditions within the analyzer.
To minimize malfunctions, ensure the system is functioning correctly. To check the integrity of the readings, ABB recommended that the analyzer and the sampling system is visually inspected on a regular basis as follows:
 Check for leaks, particularly around the sample and drain pipe connections.
 Confirm sample flow by checking delivery to the constant head unit and effluent from the drain.
 Check the liquid flow over the probe membrane / sensing surface.
 Check liquid levels in the reagent and standard solution containers.
 Check for malfunction indications on the analyzer's display.
B.2 Reagent and Standard Solutions
Any unpredictable problems may be due to the standard or reagent solutions or their flow through the analyzer. If any doubts exist regarding the integrity of these solutions, replace them with freshly prepared solutions in the early stages of the fault-finding process. Ensure that appropriate concentrations of the reagent and standard solutions are used. When changing standard or reagent solutions, replace the container also, removing the empty / used one for thorough cleaning. DO NOT top-up reagent and / or standard solutions.
Appendix B – Troubleshooting
OI/AXM630–EN Rev. J
77
B.3 Probe Malfunction
B.3.1 Ammonia Analyzer
In the event of an ammonia probe malfunction, check for leakage past the membrane. This is indicated by the internal filling solution – it incorporates a yellow-colored indicator that changes to blue if the probe membrane, or membrane seal, allows alkaline reagent to leak into the probe. If this has occurred replace the membrane – see Section 13.4, page 68. The solution keeps indefinitely.
B.3.2 Fluoride Analyzer
A noisy sensor output can be caused by excessive bubble build-up on the sensing end of the fluoride probe.