TM 10-6630-222-12&P
0005 00
OPERATOR AND UNIT MAINTENANCE MANUAL
(INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST)
FOR WATER QUALITY ANALYSIS SET: PURIFICATION (WQAS-P)
DESCRIPTION AND USE OF CONTROLS AND INDICATORS FOR TURBIDITY METER
All glassware used to contain the standards and the samples should be maintained clean, washed with cleaning solution
and rinsed with turbidity standard, 0 FTU or turbidity-free water.
Collect the samples in clean glass or plastic bottles, fit stoppers and perform the analysis quickly. If unavoidable, store
the sample in a cool, dark place, but not for longer than 24 hours . (the sample needs to be kept at room temperature
prior to the analysis).
To obtain a representative sample, gently, but thoroughly, mix it before samples are taken. Do not shake (to prevent air
bubbles) and do not let the sample settle.
It is recommended to calibrate the meter monthly with the supplied turbidity standards, 0 FTU and 10 FTU, or more
frequently for greatest accuracy.
Before inserting vials into the instrument, wipe them with a soft, lint-free tissue. Handle vials so that no fingerprints
can get on the areas where light passes (approximately 2 cm/1 inch from the bottom of the vial).
SOURCES OF INTERFERENCE
Presence of floating debris and course sediments which settle out rapidly will give false readings.
The infrared light source used for turbidity meter, according to ISO 7027 International Standard, can effectively
minimize errors due to colored dissolved substances. This effect, named "true color", is a common interference for
most commercially available instruments operating in the range of visible light.
Air bubbles and the effect of vibrations that disturb the surface of the sample will give false results.
Dirty glassware could also affect readings along with scratched or edged vials.
CALIBRATION
A monthly calibration is recommended. To check the date of last calibration, simply hold the DATE/⇒ key down.
A more frequent check of the instrument is suggested by using the supplied standard solution.
CALIBRATION PROCEDURE
Turn the meter on and wait for the display to show "----".
Press the CAL key once, the "CAL" message will blink on the display for about 6 seconds, then the calibration mode
stops.
While the "CAL" message is still blinking, press CAL again. The instrument is now in the calibration mode and a
"CL" will appear on the lower part of the display. The date of calibration can be edited now by simply pressing the
DATE/⇒ key. To scroll to the correct number press the READ/⇑ key. The default blinking parameter is the month,
on the left hand of the display (MM.DD).
To confirm the displayed data values and to go to the next step, press the CAL key once. A blinking "ZERO" message
will appear.
Take the turbidity standard bottle containing the ZERO FTU* Standard (or turbidity-free dilution water) and fill the
cuvette marked "0", if not already filled..
Note: in order to minimize any error introduced by the cuvette, it is recommended to use, during calibration, the
same cuvette you are going to use to perform the measurement.
Insert the cuvette with the turbidity standard ZERO FTU* standard solution (or turbidity-free dilution water) into the
measurement cell and press the CAL key. A blinking "SIP" message indicates that the instrument is performing the
measurement. After approximately 50 seconds the instrument will ask for the turbidity standard solution @ 10 FTU*
by displaying "10.0".
Repeat the same procedure with turbidity standard @ 10 FTU* standard solution, using cuvette marked 10.
Insert the cuvette with the turbidity standard at 10 FTU* into the measurement cell and press the CAL key again.
After approximately 50 seconds the LCD will display "----". Now the instrument is calibrated and ready for use.
0005 00-4
