7
Troubleshooting
User qualification: instructed user, see
Chapter 1.2 ‘User qualification’ on page 49
Fault
Possible cause
Remedy
Sensor cannot be cali‐
brated – display on
measuring device/
controller greater than
DPD-1 measurement.
Run in period too short.
See "Run in period".
Diaphragm cap damaged.
Replace diaphragm cap, allow sensor
to run in, calibrate it.
Troublesome substances in
the water.
Check water for troublesome sub‐
stances and remedy this.
Short circuit in the measuring
line.
Identify short circuit and eliminate the
cause.
DPD chemicals out of date.
Use new DPD chemicals, repeat cali‐
bration.
Sensor cannot be cali‐
brated – display on
measuring device/
controller lower than
DPD-1 measurement.
Run in period too short.
See "Run in period".
Deposits on the diaphragm
cap.
Remove the deposits - see "Mainte‐
nance"; replace diaphragm cap; allow
sensor to run in, calibrate it.
Sample water flow rate too
low.
Correct flow rate.
Reference electrode worn out
(showing shiny points).
Return sensor.
Air bubbles on the outside of
the diaphragm.
Remove air bubbles by tapping them
and increase flow rate if necessary.
No electrolyte in diaphragm
cap.
Fill with new electrolyte.
Electrolyte pushed out by gas
bubbles in the sample water.
Contact ProMinent.
Troubleshooting
65
