Fault Finding - Grundfos AQC-D4 Installation And Operating Instructions Manual

12. Fault finding

Observe the installation and operating instructions of the measuring amplifier and controller!
Fault
1. No display, no measuring
cell current.
2. Measured value too low.
3. Measured value too high. a) Temperature has risen since calibration.
4. Measured value
unstable.
Cause
a) Disinfection or oxidation agent missing in sample
water.
b) Poor contact of counter-electrode.
c) Interruption in electrode cable.
d) Sample water flow too low or missing.
e) Measuring electrodes faulty.
a) Measuring electrodes contaminated or made
passive by deposits.
b) Temperature has dropped since calibration.
c) Warming-up time too short prior to calibration.
d) Quantity of sample water set too low.
e) Unsuitable chlorination agent.
f) Faulty reference measurement.
g) Cleaning motor blocked.
h) Cleaning motor does not move.
b) Interference by other oxidation agents in sample
water.
a) Interferences on signal lines.
b) Air bubbles in measuring chamber.
c) Reference electrode diaphragm blocked.
d) Siphon effect at sample water outlet.
Remedy
Check the concentration using a reference
measurement.
Activate dosing.
Check the contact, and replace the socket or
plug, if necessary.
Reestablish connection, and replace damaged
cables, if necessary.
Clean the filter, and check the flow and sample
water inlet pressure.
Replace the measuring electrode.
Dismantle, clean or replace the measuring
electrode.
Recalibrate.
Observe the warming-up time prior to
calibration, then recalibrate.
Check and adjust the quantity of sample water.
Check the filter and clean, if necessary.
Only use suitable chlorination agents, and
contact your Grundfos partner.
Check the reference measurement, and analyse
the sample water.
Gently loosen the measuring electrode and
re-position.
Replace the magnetic stirring stone, cleaning
balls or slide disk.
Check the electrical tension, and replace the
motor unit, if necessary.
Recalibrate.
Analyse the sample water.
Check the used chemicals.
Check the screen.
Place the electrode correctly.
Replace the magnetic stirring stone, if
necessary.
Clean the diaphragm, and replace the
measuring electrode, if necessary.
Reduce the sample water quantity, and check
that the correct layout of is used for the outlet
tube.
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