Hach-Lange NH4D sc Ammonium Sensor - Manual (Page 35)

35
Troubleshooting
Incorrect measurement
values
Dampness inside the measuring probe/faulty
sensor electronics
Check the sensor electronics by using the test
cartridge (
section 7.2 on page 37 ).
1 Select
SENSOR-SETUP>DIAG/TEST>SERVICE>
TEST CARTRIDGE>Test cartridge
Ready? Press ENTER
2 Compare the displayed values with the guide
values. The displayed values should be in the
same range as the guide values below. Wait
for stabilization before pressing ENTER:
AMMONIUM:
SIGNAL –237.0<(–226.2 mV)<–217.0
MEAS 2263.6<(2274.4 mV)<2283.6
REF 2450.6<(2500.6 mV)<2550.6
ENTER
POTASSIUM:
SIGNAL –10.0<(–2.9 mV)<10.0
MEAS 2490.6<(2497.7 mV)<2510.6
REF 2450.6<(2500.6 mV)<2550.6
ENTER
TEMPERATURE VALUES:
TEMP 24.5<(24.8 ºC)<25.5/
76.1<(76.6ºF)<77.9
ENTER
3 If the test cartridge data are within range, the
sensor electronics are functional:
Test cartridge
OK
ENTER
If the test cartridge data are not within this
range or if the test cartridge check is not
successful, contact our service department.
Potassium concentrations too high (>700 mg/l;
with small ammonium concentrations)
Switch off potassium compensation
Unstable measurement
values
Air bubbles, depth of immersion
Check the installation
Check the configuration of the cleaning unit
Dampness at the contacts of the sensor cartridge
Dry the contacts with a cloth, some paper or
hairdryer.
Check the opaque gasket for damage and
the correct position of the gasket.
Screw the locking ring on.
Note: Use the cap of the storage container as
a tool/screwing aid for the locking ring.
Sensor membrane damaged Check installation/replace sensor cartridge
Reference element damaged Check installation/replace sensor cartridge
6.3.1 Troubleshooting during operation (continued)
Symptom Possible cause Corrective actions