Fault Finding; Maintenance; Disposal - Grundfos Conex DIA-2 Installationsanleitung

12. Fault finding

Faults during the measurement, see
Note installation and operating instructions for
the electrode or measuring cell.
Fault
1. No display following start-up.
2. With pH measurement:
Display permanently indicates pH
approximately 7.
– With measurement of oxidisers:
Display permanently indicates
zero.
3. Display permanently at full-scale
value.
4. Display with measured value
unsteady.
5. With measurement of oxidisers:
insufficient sensitivity of
measuring cell.
6. With pH measurement:
Display with measured value
reacts extremely slowly.
7. With pH measurement:
error message during calibration.
8. Device cannot be set.
9. Faulty control.

13. Maintenance

The device is maintenance-free.
Repairs can only be carried out in the factory by
authorised personnel.
Cause
a) No power supply.
a) Short-circuit in cable between
measuring cell and instrument
amplifier, moisture in connectors.
a) Open circuit in cable between
measuring cell and instrument
amplifier.
a) Interferences on cable from
electrode/measuring cell.
b) pH and redox measurement:
air in sample-water flow.
c) pH measurement: sample-water
flow interrupted.
d) Cable between electrode/measuring
cell and instrument amplifier broken.
e) Sensor/electrode faulty.
a) Measuring cell contaminated or
passivated by deposits.
a) Electrode aged.
b) Electrode dirty.
a) Wrong buffer solution used.
b) Electrode aged.
c) Electrode dirty.
a) Incorrect code set (device protected
against adjustment).
a) Device is incorrectly parameterised. Check the settings and match

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.
Remedy
Connect the power supply.
Check the connection cable
and eliminate short-circuit and
moisture.
Check the connection cable
and reestablish connection.
Check that the display is
properly connected.
Check the sample-water supply
system (pipes, etc.) and make
changes, if necessary.
Check the sample-water supply
system (pipes, etc.) and make
changes, if necessary.
Check the connection cable
and reestablish connection.
Replace the sensor/electrode.
Disassemble the measuring
cell, and clean the electrode
surface.
Replace the electrode.
Clean the electrode.
Use the correct buffer solution.
Replace the electrode.
Clean the electrode.
See section 11.5.8 Code
function.
them to the local conditions.
If necessary, reset the device to
the factory settings.
53