ZERO
READ
ClO2
C L O 2
to Increase
output
to Decrease
output
SECTION 8.0
CALIBRATION
FIG. 6
SECTION 9.0
SENSOR STORAGE
IMPORTANT NOTE: SENSORS ARE SUPPLIED FACTORY CALIBRATED WITH A
4-20mA SIGNAL OUTPUT CORRESPONDING TO THEIR SPECIFIC RANGE (0-2,
0-5 OR 0-10ppm). SPAN CALIBRATION IS NECESSARY WHEN RECEIVING A
NEW SENSOR SINCE YOUR CONDITIONS MAY VARY FROM THOSE USED AT
THE FACTORY FOR SPAN CALIBRATION. THE ZERO POINT CALIBRATION IS
NOT NECESSARY SINCE THE ZERO SETTING IS VERY STABLE.
PERIODIC CALIBRATION ( ABOUT ONCE PER WEEK) IS RECOMMENDED. THIS
IS USEFUL IN TRACKING SENSOR FAILURES AS WELL.
8.1 Removal of cord grip to access ZERO and SPAN
potentiometers inside the sensor body:
a. Remove top nut of cord grip as shown in FIGURE 4.
b. Remove remaining cord grip as shown in FIGURE 5. A wrench
may be required.
8.2 Slope Calibration:
a. Determine the free chlorine content using a diethyl-p-
phenylenediamine (DPD) colorimeter test kit (see FIGURE 9.),
not included with ClO2 sensor and flow cell.
b. Measure Free Chlorine content with sensor. Make sure that
calibration flow rate and pH matches flow rate when
measuring sample since probe output is flow rate and pH
dependent. Make sure pH is within 5.5-8.0 range.
c. Adjust the span potentiometer to the desired mA (see
FIGURES 9 & 9A)
c. Repeat this slope calibration one day after sensor is
initially installed.
d. Repeat the slope calibration monthly.
9.0 STORAGE. Store sensor at 5
o
C- 50
o
C ONLY and maximum
humidity of 90% (non-condensing).
a. Short Term Storage (1 week or less): Store in Flow cell
with water to prevent the probe from drying out.
b. Intermediate Term (1 week to 1 month): Store in cap,
bottle, or beaker with water to keep membrane wet.
c. Long Term (1 month or longer): Remove Membrane
Cap and store completely immersed in tap water. Turn
sensor upright and shake it to remove fill solution from
inside the sensor.
d. Electrolyte bottle shelf-life = 1 year from date of
manufature(see expiration date on bottle)
PRODUCT INSTRUCTION SHEET
Left
pote
n
tiometer
(Zero adju
s
t)
R
ight
pote
n
tiometer
(
S
pa
n
adju
s
t)
C
able
FIG. 7
FIG. 8
FIG. 9
Note: The DPD method
for Free chlorine mea-
surement is not selective
for free chlorine alone.
Other oxidants in the
water can also be mea-
sured as free chlorine.
FIG. 4
FIG. 5
Free Cl
Free Cl
Parts covered by this product instruction sheet include: FCLTX-100 Series
M4679/0708 page 4 of 6
