5.
Remove the sensor from the pH 7 buffer and rinse. Place the sensor in a pH 4 buffer solution and stir
for a minute or two. Allow the reading to stabilize and adjust the pH SPAN TRIIPOT (R855) until the
LCD display reads 4.00. Repeat steps 4 and 5 to check that the pH zero and pH SPAN adjustment
hasn't changed. The instrument is now calibrated for pH.
6.
To calibrate the analyzer in the TFC/AUTO MODE place the pH sensor, the chlorine sensor and the
solution ground in a beaker of chlorine demand free water on a magnetic stirrer. Do not run the stirrer
so fast as to create air bubbles in the solution. Add 1 ml. of a pH 4 or 5 buffer. Allow the sensor to
stabilize for about 3 to 5 minutes.
7.
Set the display switch to chlorine.
8.
Set the range switch to its lowest setting (0-1 ppm) and adjust the CL ZERO TRIMPOT (R828) until the
LCD display reads 0.00.
9.
Now add a dilute hypochlorite solution drop wise until a reading of between 25 to 50% of range is
obtained. Allow the solution to stabilize for about 2 to 3 minutes. (Note: To prepare dilute hypochlorite
solution, add 10 cc of 5% bleach, such as clorox to 100 cc of water).
10.
Withdraw sample of solution and check for concentration of chlorine using DPD-50 test kit or other test
method.
11.
Adjust the CL SPAN TRIMPOT (R820) to the value obtained with the test kit or other test method used.
The analyzer is now calibrated and the sensor may be placed in the sample stream.
CALIBRATION PROCEDURE II
This procedure may be used to calibrate the analyzer and sensor while it is in the process water.
1.
Turn the analyzer on and prepare it for use in accordance with steps 1 through 5 of calibration
procedure I-FAC MODE.
2.
Return the sensor to the process stream. Allow 2 or 3 minutes for meter to stabilize.
3.
After the 2 or 3 minutes, withdraw a sample from the process water and determine concentration of
chlorine using DPD-50 test kit or other recommended test.
4.
Adjust CL SPAN TRIMPOT (R 820) to the value obtained with the test kit or test method used. The
unit is now calibrated.
NOTE
The chlorine concentration in the process stream should not change during the
calibration process.
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