Aztec 600 ISE ammonia and fluoride
Single-stream ion-selective analyzers
Appendix B – Troubleshooting
78
OI/AXM630–EN Rev. I
Fault
Possible Cause
Remedy
Noisy electrode
output
Air bubbles present on probe tip
1. Remove probe to clear air bubbles and refit
2. Check sample supply and check for air leaks
Heated block temperature too high
Lower temperature setting in configuration
Osmotic effects due to high
concentrations of dissolved species
Take appropriate measures to ensure the sample is suitable for
measurement
Ammonia analyzers only –
Interferents in sample (sample may
contain high concentrations of anionic
detergents)
Take appropriate measures to ensure the sample is suitable for
measurement
Ammonia probe membrane fault
Check membrane is not punctured, creased, blistered or loose –
adjust or replace membrane as required
Faulty electrical connections
Check BNC connector and other probe electrical connections
Inadequate mixing of the reagent
solution
Ensure mixer is in place (if required)
Ammonia probe
response slow
Probe membrane damaged or
sensing end fouled
1. Check membrane is not punctured, creased, blistered or loose
– adjust or replace membrane as required
2. Carefully clean probe membrane surface with jet of clean
water from wash bottle or syringe.
Fluoride probe
response slow
Probe sensing end fouled
Clean probe end face
Excessive reading
drift
Heated block assembly temperature
control faulty
1. Check temperature setting in configuration
2. Check Pt1000
Electrode unstable
Ammonia
– 1. Membrane loose – adjust membrane
2. Membrane swollen or damaged – replace
membrane
3. Filling solution exhausted – replace filling
solution
4. If fault persists, replace electrode
Fluoride
– Replace probe
Faulty reference electrode
Ammonia
– Replace glass electrode
Fluoride
– Replace probe
High readings
Ammonia probe response slow
1. Check probe and replace membrane if required
2. Check reference electrode for signs of stripping of chloridised
layer
Calibration configuration values input
incorrectly
Check calibration input values and calibration solutions values.
Use mV Offset to give indication – the further from 0 mV, the more
likely it is that the standard values are different to the true standard
concentrations
Sample contaminated
Take appropriate measures to ensure the sample is suitable for
measurement
Table B.1 Faults, Causes and Suggested Remedies
