Myron L 6Pfc and 4P - Manual (Page 38)

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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. 32.
Inaccurate ph readings (6Pfc) 1. pH calibration needed. Ref. pH Cal.,
pg. 17.
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. 36.
No response to ph changes (6Pfc) Sensor bulb is cracked or an
electromechanical short caused by an
internal crack.
Replace pH/ORP sensor. Ref. Replacement pH/ORP Sensor, pg. 37.
Will not adjust down to ph 7 (6Pfc) pH/ORP sensor has lost KCl. Clean and rejuvenate sensor (ref. Cleaning Sensors, pg. 32) and recalibrate. If no
improvement, replace pH/ORP sensor (ref. Replacement pH/ORP Sensor, pg. 37).
ph readings drift or respond slowly to
changes in buffers/samples or “FAC”
is displayed repeatedly (6Pfc)
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. 32) and recalibrate. If no
improvement, replace pH/ORP sensor (ref. Replacement pH/ORP Sensor, pg. 37).
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. 32.
2. Minimize test sample exposure to air by taking a flowing sample.
Ref. Measuring Resistivity, pg. 9.
Unable to calibrate Conductivity/
TDS
Film or deposits on electrodes. Clean cell cup and electrodes. Ref. Cleaning Sensors, pg. 32.
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. 9.
Low ORP Reading
Slow or no response to ORP changes
(6Pfc)
ORP platinum electrode is dirty. Check the ORP sensor functioning. Take an ORP reading of Myron L pH/ORP
Sensor Storage Solution (ref. pH Sensor Storage Solution (6Pfc), pg. 36). If the
reading is outside the range of 350-400 mV, clean ONLY the platinum ORP
electrode with Myron L ORP Conditioner solution-soaked cotton swab (ref. ORP
Sensor Conditioner Solution (6Pfc), pg. 36), being careful not to touch the swab to
the glass bulb of the pH sensor.