Walchem WebMaster - 4 Troubleshooting; The Disinfectant Reading Is Much Lower than the Manual Analysis

15
Zero Calibration
1. Remove the sensor from the flow cell and place it in a beaker of clean,
oxidizer-free water.
2. Allow the sensor 15 minutes to equilibrate to the water temperature.
3. Go to the Zero Calibration menu of the controller. Refer to the controller
instructions.
4. Stir the water with the sensor until the mV reading is stable for at least 5
minutes.
5. When the reading is stable, continue to the final steps of the calibration.
6. Return the sensor to the flow cell and check for leaks.
One Point Process Calibration
1. Ensure that the sensor is conditioned and equilibrated to the temperature
of the sample.
2. Ensure that the sample flow rate is between 30 and 100 liters/hour.
3. Perform a DPD test or other manual analysis on the sample water.
4. Go to the One Point Process Calibration menu of the controller. Refer to
the controller instructions.
5. When the reading is stable, continue to the final steps of the calibration.
NOTE: Disinfectant concentration can change rapidly in the sample!
Minimize the time between performing the DPD test or manual analysis and
finishing the calibration!
4.0 Troubleshooting
The disinfectant reading is much lower than the manual
analysis
Possible Causes
Corrective Actions
Insufficient conditioning
Wait for the appropriate amount of time
before attempting a calibration.
Insufficient sample flow
Increase flow rate to between 30 and 100 liter
per hour.
Air bubbles on membrane
Dislodge bubbles. Adjust flow rate higher if
necessary.
Dirty membrane
Clean membrane
Loose membrane cap
Tighten membrane cap.
Faulty membrane
Replace membrane cap.
High Pressure
Reduce pressure to below 1 atmosphere and
refill cap with electrolyte
No electrolyte fill solution in
membrane cap
Fill membrane cap with electrolyte. Replace
membrane cap if it will not hold solution.
Faulty sensor
Replace sensor
Faulty analysis equipment or
reagents
Consult test equipment instructions