Hach-Lange AMTAX indoor sc - Manual (Page 63)

63
Troubleshooting
Refer to Table 12 for additional errors messages.
The electrode slope is between –60 and
–65 mV and the 3 calibration values are
all significantly offset to the positive
range.
- The electrolyte is almost empty
- electrode body leaking
- Membrane cap leaking
- Electrolyte almost completely
evaporated after extended operation
- Tighten membrane cap
- Leaking electrode body: order new
electrode
All mV values for the calibration data
only differ in the figures after decimal
separator (almost constant).
- Amplifier board faulty - Fit new amplifier board
Table 11 Error messages (continued)
Error description Diagnostics Solution
Table 12 Additional error messages
Error description Diagnostics Solution
The calibration values fluctuate
excessively
- Electrode faulty
- Replace electrolyte and membrane
cap
The slope is between –40 and –45 mV
after the calibration
- The measuring range 0.05–20 mg/L
NH
4
–N is adjusted and the wrong
standard solutions 10 and 50 mg/L
NH
4
–N are used.
- Insert the right standard solutions and
complete the procedure for changing the
measuring range in the service menu.
The slope decreases, the membrane
can be damaged. The values of the
electrode slope can decrease after
1–2 weeks to –40 mV and –50 mV.
- Membrane is damaged (for example
with silicone oil).
- Remove the measurement chamber
completley
- Clean it thoroughly
A large continuous drift is on the
measured values (up to 2 mg in 24 h).
- Electrode cap is damaged. The
electrolyte crystallize on the cover/cap
and evaporate very quickly.
- Re-new electrolyte
- Insert new electrode
Fluctuations of measured values and
interference of the calibration in the
lower measuring range. - Insufficient sample when sample is
required for the determination of the
zero value
- Make sure that sufficient sample is
available
All three electrode values increase
within 24 h over 8 mV to positive values. - The ectrolyte level dropped out below
4 mL.
- Empty the electrode body, rinse it with
distilled water and fill it with new
electrolyte.