Myron L 6Psi and 4P - Manual (Page 39)

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Symptom Possible Cause
No display, even though
measurement key pressed
Battery weak or not connected.
Inaccurate ph readings
(6Psi)
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.
No response to ph changes
(6Psi)
Sensor bulb is cracked or an
electromechanical short caused by
an internal crack.
Will not adjust down to ph 7
(6Psi)
pH/ORP sensor has lost KCl.
ph readings drift or respond
slowly to changes in
buffers/samples
or
“FAC” is displayed
repeatedly (6Psi)
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.
Unstable
Conductivity/TDS/
Resistivity readings
1. Dirty electrodes.
2. Test samples greater than 1
megohm.
Unable to calibrate
Conductivity/TDS
Film or deposits on electrodes
.
Resistivity readings much
lower than expected
1. Contamination from previous
sample or from pH sensor well.
2. Carbon dioxide in test sample.
Corrective Action
Check connections or replace battery.
Ref. Battery Replacement, pg. 32.
1. Recalibrate instrument.
2. Thoroughly rinse sensor well.
3. Recalibrate using fresh buffers.
Ref. pH Buffer Solutions, pg. 36.
Replace pH/ORP sensor.
Ref. Replacement pH/ORP Sensor, pg. 37.
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).
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).
1. Clean cell cup and electrodes.
Ref. Cleaning Sensors, pg. 32.
2. Minimize test sample exposure to air.
Ref. Measuring Resistivity, pg. 10.
Clean cell cup and electrodes.
Ref. Cleaning Sensors, pg. 32.
1. Rinse cell cup more thoroughly before
measurement. Ensure pH cap is snugly
in place.
2. See Measuring Resistivity, pg. 10.