Pr
o
Minent
®
40
10
Troubleshooting
Troubleshooting must take account of the whole measuring system. The
measuring system consists of (see fig. 2)
1) Measurement/control device
2) Electrical leads and connectors
3) In-line probe housing and hydraulic connections
4) Sensor
The possible causes of failure listed in the following table primarily refer
to the sensor. Before commencing troubleshooting please ensure that the
operating conditions in “Technical data”, Chapter 14 are met:
a) Chlorine content lies within the corresponding measurement range of
the sensor
b) Constant pH in the range 6.5 - 9.5
c) Constant temperature in the range 4 - 45
°
C
d) Conductivity: 0.03 - 40 mS/cm
e) Flow: 20 - 100 l/h
The sensor simulator (DULCOMETER
®
Simulator order no. 1004042) is
recommended for locating a controller malfunction. You will find a detailed
description of troubleshooting of the controller in the operating instructions
of DULCOMETER
®
D1C, chlorine.
If the value measured by the sensor differs significantly from that of the DPD
method you need to first consider all possible malfunctions of the DPD
photometric method. If necessary, repeat the DPD measurement several
times.
Fault
Possible Cause
Remedy
Sensor can not be calibrated.
1) Run-in time too short
See Chapter 8.1 “Run-in period”
Measured value
higher
than
2) Membrane cap damaged
Replace membrane cap, run in
DPD-measurement
sensor and calibrate
(see chapter 6, 8.1, 8.2)
3) Interfering substances in sample
Examine sample water for
water (see “cross sensitivity” in
interfering substances and remedy
Chapter 14, Technical data)
4) Short-circuit in signal lead
Locate and eliminate short-circuit
5) Distance between working
Screw the membrane cap tightly
electrode and membrane too great
onto the electrode shaft, so that
no gap can be seen anymore
6) DPD chemicals spent
Use new DPD chemicals, repeat
calibration
7) pH-value < pH 6.5
Raise pH-value (6.5-9.5)
Troubleshooting
BA_DT_106_12_09_4spr.p65
15.12.2009, 10:26 Uhr
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