Xylem WQ pH SENSORS - Manual (Page 14)

Global Water
800-876-1172
• globalw.com
- 14 -
VIII. ORP/Redox Sensor
a. ORP/Redox sensor specifications.
Output:
4-19 mA
Range: -500mV to +500mV
Accuracy: 2% of full scale
Operating Voltage: 10-36VDC
Current Draw: 13.5 mA plus sensor output
Warm Up Time: 3 seconds minimum
Operating Temp: 0° to +55°C
Size: 1” diameter x 10 ½” long
Weight: 1 lb.
b. The sensing element is covered with a protective cap while at the
Global Water facility to prevent the sensor from becoming damaged.
This cap must be removed prior to sensor installation or the readings
will be in error. To remove the cap, gently pull the rubber tab on the
end of the cap and the cap should come off. Replace the protective
shield. Note: Save the cap for future use.
c. The ORP/Redox sensor is a three-wire sensor. Three wire sensors
use the red wire for positive voltage, the white wire for the output
signal, and the black wire for ground. Warning: Always connect the
sensor with the power turned off.
d. The ORP/Redox sensor must be stored where the sensing element
remains wet or the sensing element will be damaged. It can be stored
in a container of clean water or a wet sponge can be placed inside the
protective cap shipped with the sensor. Place the cap over the
sensing element to keep it wet. The sensor can then be stored on a
shelf or hung on a wall.
e. ORP (Oxidation Reduction Potential) is a measure of the oxidation
activity of the water. If the oxidation activity is high it will rust a piece
of iron quickly. ORP is also used as an alternative way to measure
chlorine concentration, since water high in chlorine (a strong oxidizer)