Grundfos Conex DIA-2, Installation And Operating Instructions Manual

Page: 53 / 612

English (GB)
53
12. Fault finding
13. Maintenance
The device is maintenance-free.
Repairs can only be carried out in the factory by
authorised personnel.
14. Disposal
This product or parts of it must be disposed of in an
environmentally sound way. Use appropriate waste
collection services. If this is not possible, contact the
nearest Grundfos company or service workshop.
Note
Faults during the measurement, see
installation and operating instructions for
the electrode or measuring cell.
Fault Cause Remedy
1. No display following start-up. a) No power supply. Connect the power supply.
2. With pH measurement:
Display permanently indicates pH
approximately 7.
– With measurement of oxidisers:
Display permanently indicates
zero.
a) Short-circuit in cable between
measuring cell and instrument
amplifier, moisture in connectors. Check the connection cable
and eliminate short-circuit and
moisture.
3. Display permanently at full-scale
value. a) Open circuit in cable between
measuring cell and instrument
amplifier. Check the connection cable
and reestablish connection.
4. Display with measured value
unsteady. a) Interferences on cable from
electrode/measuring cell. Check that the display is
properly connected.
b) pH and redox measurement:
air in sample-water flow. Check the sample-water supply
system (pipes, etc.) and make
changes, if necessary.
c) pH measurement: sample-water
flow interrupted. Check the sample-water supply
system (pipes, etc.) and make
changes, if necessary.
d) Cable between electrode/measuring
cell and instrument amplifier broken. Check the connection cable
and reestablish connection.
e) Sensor/electrode faulty. Replace the sensor/electrode.
5. With measurement of oxidisers:
insufficient sensitivity of
measuring cell. a) Measuring cell contaminated or
passivated by deposits. Disassemble the measuring
cell, and clean the electrode
surface.
6. With pH measurement:
Display with measured value
reacts extremely slowly. a) Electrode aged. Replace the electrode.
b) Electrode dirty. Clean the electrode.
7. With pH measurement:
error message during calibration. a) Wrong buffer solution used. Use the correct buffer solution.
b) Electrode aged. Replace the electrode.
c) Electrode dirty. Clean the electrode.
8. Device cannot be set. a) Incorrect code set (device protected
against adjustment). See section 11.5.8 Code
function .
9. Faulty control. a) Device is incorrectly parameterised. Check the settings and match
them to the local conditions.
If necessary, reset the device to
the factory settings.