Hach-Lange AMTAX indoor sc - Manual (Page 62)

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Troubleshooting
7.3 Troubleshooting the Electrode
The electrode data are saved in the AMTAX sc CALIB. DATA menu
or in the event logger.
Typical electrode values (note sign):
Table 10 contains typical electrode data for a new inserted
electrode with new electrolyte and membrane cap.
The zero value is always the most positive value and the standard 2
value is always the most negative value in a calibration. The
standard 1 is always between the zero value and the standard 2
value.
When starting up an electrode, the slope increases to the final
value (ideal between –58 and –63 mV) and remains there with
minor fluctuations.
The error descriptions for the electrode in Table 11 and Table 12
are related to the error/warning "electrode slope" or "false elec.
data".
Table 10 Typical electrode values
Description
MR 1
(0.02–5 mg/L NH4–N)
MR 2
(0.05–20 mg/L NH4–N)
MR 3
(1–100 mg/L NH4–N)
MR 4
(10–1000 mg/L
NH4–N)
Slope –55 to –67 mV
Slope warning –50 to –55 mV or –67 to –70 mV
Slope error 0 to –50 mV or –70 to –150 mV
mV zero –205 to +5 mV 20 to 120 mV 20 to 120 mV 20 to 120 mV
mV standard 1 –200 to –140 mV –30 to 30 mV –25 to –85 mV –70 to –130 mV
mV standard 2 –240 to –180 mV –30 to –90 mV –70 to –130 mV –130 to –190 mV
Table 11 Error messages
Error description Diagnostics Solution
The calibration values for the standards
are both above the mV zero value.
- Reagent empty
- Reagent pump faulty
- Fittings leaking - New reagent
- Replace reagent pump
- Tighten fittings
The calibration values for the two
standards and the mV zero value are all
indicating very similar values.
- Electrode faulty
- Electrolyte empty - Re-new electrolyte
- Insert new electrode
Only the mV standard 1 value is above
the mV zero value. - Standard 1 empty
- Piston pump leaking
- New standard 1
- Replace piston & cylinder (piston
pump)
Only the mV standard 2 value is above
the mV zero value. - Standard 2 empty
- Piston pump leaking
- New standard 2
- Replace piston & cylinder (piston
pump)
The mV zero value is in the negative
range.
- Cleaning solution empty
- Cleaning pump faulty
- Fittings leaking - New cleaning solution
- Replace cleaning pump
- Tighten fittings