Faults, Fault Detection And Troubleshooting - ProMinent DULCOTEST CDE 2-mA-2 ppm Montage- Und Betriebsanleitung

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Faults, Fault Detection and Troubleshooting

User qualification: instructed user, see
Tab. 3: Information on Troubleshooting and Fault Elimination
Fault
The sensor cannot
be calibrated and
sensor's measured
value is greater
than the DPD
measurement.
The sensor cannot
be calibrated and
the sensor's meas‐
ured value is lower
than the DPD
measurement.
Faults, Fault Detection and Troubleshooting
Ä Chapter 2.3 „Users' qualifications" on page 47
Possible cause
Run in period too short.
Diaphragm cap damaged.
Troublesome substances in the
water.
Short circuit in the measuring line.
Distance between diaphragm/elec‐
trode is too great.
DPD chemicals out of date.
pH value < pH 6.
Run in period too short.
Sample water flow rate too low.
Air bubbles on the outside of the dia‐
phragm.
Surfactants in the sample water (dia‐
phragm is transparent).
Deposits have blocked the dia‐
phragm.
Deposits on the diaphragm cap.
No electrolyte in the diaphragm cap.
Reference electrode (2) worn out
(showing shiny points).
Remedy
Observe the run in period.
Replace diaphragm cap.
Check water for troublesome sub‐
stances and remedy this.
Identify short circuit and eliminate.
Screw the diaphragm cap to the
stop.
Use new DPD chemicals, repeat cal‐
ibration.
Increase pH value (pH 6 ... 9.5).
Observe the run in period.
Correct sample water flow.
Increase the sample water flow
within the permitted range.
Remove surfactants and replace
diaphragm cap.
Allow sensor to run in and calibrate;
use a CDP type sensor if necessary.
Replace diaphragm cap; allow
sensor to run in and calibrate.
Fill with new electrolyte.
Return sensor for regeneration.
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