Walchem WebMaster ONE Instruction Manual page 165

ORP High Alarm
This error message indicates the ORP reading exceeds the user-programmed maximum allowable
value.
Possible Causes
The programmed value is too close to the
ORP set point.
Slow ORP electrode response, dirty
electrode.
Control direction set incorrectly.
Control device set at too high a flow rate.
Chemical supply empty.
Metering pump is siphoning.
If a brominator, solenoid valve is stuck open.
The ORP dead band is set too high.
Faulty control device wiring.
ORP output relay is stuck closed.
Blown fuse.
Corrective Actions
Go to the ORP Input Page and make sure
that the High Alarm Limit is more than 50 mV
above the set point plus the dead band.
Clean and calibrate the ORP electrode as
described in Section 7.4 above. If the
calibration fails, refer to the ORP Calibration
Failure troubleshooting above.
For oxidizer feed the control direction should
be "force higher", for reducer "force lower".
Go to the ORP Output Page and make sure that
the correct control direction is selected.
Reduce the flow rate of the control device.
Replenish chemical supply.
Repair or install an anti-siphon valve.
Repair or replace the solenoid valve.
Go to the ORP Output Page and change the
dead band to be as low as possible to prevent
the ORP relay from chattering. If the ORP
reading fluctuates by +/- 2 mVs, then a dead
band of 5 mV is sufficient.
Correct wiring.
Replace the relay board.
Replace fuse (F2 or F3).
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