Myron L 9PTK - Manual (Page 56)

52
Xviii. trOUbleshOOting chart
symptom Possible cause corrective action
No display, even though
measurement key pressed
Battery weak or not connected. Check connections or replace battery. Ref. Battery Replacement, pg. 50.
Inaccurate ph readings 1. pH calibration needed. Ref. pH Cal.,
pg. 33.
2. Cross-contamination from residual pH
buffers or samples in sensor well.
3. Calibration with expired pH buffers.
1. Recalibrate instrument.
2. Thoroughly rinse sensor well.
3. Recalibrate using fresh buffers. Ref. pH Buffer Solutions, pg. 55.
No response to ph changes Sensor bulb is cracked or an
electromechanical short caused by an
internal crack.
Replace pH/ORP sensor. Ref. Replacement pH/ORP Sensor, pg. 56.
Will not adjust down to ph 7 pH/ORP sensor has lost KCl. Clean and rejuvenate sensor (ref. Cleaning Sensors, pg. 50) and recalibrate. If no
improvement, replace pH/ORP sensor (ref. Replacement pH/ORP Sensor, pg. 56).
ph readings drift or respond slowly to
changes in buffers/samples or “Fac”
is displayed repeatedly
1. Temporary condition due to memory” of
solution in pH sensor well for long periods.
2. Bulb dirty or dried out.
3. Reference junction clogged or coated.
Clean and rejuvenate sensor (ref. Cleaning Sensors, pg. 50) and recalibrate. If no
improvement, replace pH/ORP sensor (ref. Replacement pH/ORP Sensor, pg. 56).
Unstable conductivity/tDs/
resistivity readings
1. Dirty electrodes.
2. Actual resistance is changing due to
atmospheric contamination.
1. Clean cell cup and electrodes. Ref. Cleaning Sensors, pg. 50.
2. Minimize test sample exposure to air by taking a flowing sample.
Ref. Measuring Resistivity, pg. 14.
Unable to calibrate conductivity/
tDs
Film or deposits on electrodes. Clean cell cup and electrodes. Ref. Cleaning Sensors, pg. 50.
resistivity readings much lower than
expected
1. Contamination from previous sample or
from pH sensor well.
2. Carbon dioxide in test sample.
1. Rinse cell cup more thoroughly before measurement. Ensure pH cap is snugly in
place.
2. See Measuring Resistivity, pg. 14.
alkalinity or hardness titration with
calibration solution value not as
stated on bottle
1. Method error.
2. Dirty Cell Cup.
3. Dirty pipette.
4. Faulty pipette.
5. Contaminated calibration solution.
1. Repeat titration.
2. Clean cell cup and electrodes. Ref. Cleaning Sensors, pg. 50.
3. Clean pipette per manufacturer’s instructions.
4. Use a new pipette.
5. Use fresh calibration solution. Be sure to use a new tip for each type of solution
measured.
Low Reading
Slow or no response to OrP changes
ORP platinum electrode is dirty. Clean ORP electrode with ORP conditioner. Ref. Cleaning Sensors, 2. pH/ORP
Sensor, pg. 50.