TM 10-6630-222-12&P
0004 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 ULTRAMETER 6P
Press < /MR> repeatedly until you pass theCLR ALL and the C-F locations. The display will
3.
show a "FAC SEL" (See figure to the right).
FAC
4.
Press <CAL/MCLR> to accept the resetting.
SEL
CALIBRATION INTERVALS
There is no simple answer as to how often one should calibrate an instrument. The Ultrameter is designed to not require
frequent recalibration. The most common sources of error were eliminated in the design, and there are no mechanical
adjustments. Still, to ensure specified accuracy, any instrument has to be checked against chemical standards occasionally.
A.
Suggested Intervals
On the average, we expect calibration need only be checked monthly for the Conductivity, RES or TDS functions. The pH
function should be checked every 2 weeks to ensure accuracy. Measuring some solutions will require more frequent
intervals.
B.
Calibration Tracking Records
To minimize your calibration effort, keep records. If adjustments you are making are trivial for your application, you can
check less often. Changes in conductivity calibration should be recorded in percent. Changes in pH calibration are best
recorded in pH units.
Calibration is purposely limited in the Ultrameter to 5% for the conductivity cell because more than that indicates damage,
not drift. Likewise, calibration changes are limited to 1 pH unit because more than that indicates the end of the sensor
lifetime, and it should be replaced.
C.
Conductivity, RES, TDS Practices to Maintain Calibration
1.
Clean oily films or organic material from the cell electrodes with foaming cleaner or mild acid.
Do not scrub inside the cell.
2.
Calibrate with solutions close to the measurements you make.
Readings are compensated for temperature based on the type of solution. If you choose to measure tap water with a KCL
compensation, which is often done, and you calibrate with 442 solution because it is handy, the further away from 25C
you are, the more error you have. Your records of calibration changes will reflect temperature changes more than the
instrument's accuracy.
3.
Rinse out the cell with pure water after making measurements. Allowing slow dissolving
crystals to form in the cell contaminates future samples.
4.
For maximum accuracy, keep the pH sensor cap on tight so no fluid washes into the conductivity
cell.
D.
pH and ORP Practices to Maintain Calibration
1.
Keep the sensor wet with Storage Solution.
2.
Rinse away caustic solutions immediately after use.
Ultrameters should be rinsed with clean water after use. Solvents should be avoided. Shock damage from a fall may cause
instrument failure.
0004 00-9
