100
Sensor placed in the direct path of electrical current flow
Relocate sensor
Incorrect temperature reading or setting
Ensure that the temperature is accurate
Incorrect cable length or wire gauge setting
Set to the correct values
Faulty sensor
Replace sensor
8.1.5 ORP Sensors
The calibration will fail if the adjustment to the gain is outside of 0.5 to 1.5, or if the calculated offset is outside of
-300 to 300.
Possible Cause
Corrective Action
Dirty electrode
Clean electrode
Improper wiring of sensor to controller
Correct wiring
Faulty electrode
Replace electrode
Faulty preamplifier
Replace preamplifier
8.1.6 Disinfection Sensors
The calibration will fail if the adjustment to the gain is outside of 0.2 to 10.0, or if the calculated offset is outside of
-40 to 40.
Possible Cause
Corrective Action
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.
Air bubbles in electrolyte
Refill membrane cap with electrolyte.
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.
Improper wiring of sensor to controller
Correct wiring
Faulty sensor
Replace sensor
Faulty analysis equipment or reagents
Consult test equipment instructions
Sample contaminated with interfering molecule (refer to
Sensitivity specification in sensor instructions)
Remove source of contamination
8.1.7 Analog Inputs
The calibration will fail if the adjustment to the gain is outside of 0.5 to 2.0, or if the calculated offset is outside of
-2 to 2 mA.
Possible Cause
Corrective Action
Improper wiring of sensor to controller
Correct wiring
Faulty sensor
Replace sensor
