In order to validate the readings of your ORP probe, we want to insure that the probe has been properly cleaned before testing. Please refer to the manufactures instructions on cleaning the probe or refer to our Cleaning Probe Article for proper cleaning instructions.
Conducting a separate test on your ORP probe, independent of The Attendant’s readings, helps verify accuracy. Sometimes, probe wires or the chemistry board may be damaged, leading to incorrect readings.
Items needed for proper testing
- ORP Calibration Solution unopened (225 mV)
- Multimeter capable of measuring DC mV
It is crucial to never allow the probe to remain dry for more than 5 minutes during testing, as doing so will cause irreversible damage to the probes and they will need to be replaced.
ORP Validation with Multimeter:
Follow the steps below.
Disconnect the wire connecting the probe to The Attendant by twisting the connector (under the rubber protective sheath) counter-clockwise and pulling it out.
Turn off the the water to the flow cell or plumbing so the probe can be removed.
Remove the probe from the plumbing or flow cell.
Rinse the ORP probe well with demineralized, deionized (DO), or reverse osmosis (RO) water.
Open the ORP calibration/storage solution 225 mV and optionally pour some fluid into a separate, clean (nonmetallic) container small enough to submerge the tip of the ORP probe into.
Place the ORP probe tip into the room temperature solution (temperature of solution should be approximately 25°C / 77°F)
Set your multimeter to DC mV mode. Place one test lead on the center pin of the probe connection and the other lead on the outer metal connection, as shown in the image to the right. Compare the measured values to the solution. The probe is working correctly if the offset is ± 10 mV when comparing the reading with the Calibration solution.
A deviation of 50 to 100 mV indicated that the sensor needs to be replaced or cleaned.