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Troubleshooting - pH
Display Condition
During EasyCal:
"Out of Range
Use Manual CAL"
During EasyCal:
"Same Buffer"
During CALIBRATE Std:
"Standard too close to Slope!"
During CALIBRATE Slope:
"Slope too close to Standard!"
During CALIBRATE:
"Out of Range
Check Sensor"
During normal operation:
Constant "15.00 pH"
or
constant "0.00 pH"
with good temp value
During normal operation:
"Check Sensor?"
The mV value from the sensor when placed in a 7 pH buffer represents the sensor offset. Signet recommends servicing/replacing the
sensor when the offset exceeds 50 mV.
The 3-2719 pH calibration tool allows simple system troubleshooting.
‡ SIGNET 8750-1 pH/ORP Transmitter
Possible causes
1. Required 4, 7 or 10 buffers not being
used.
2. Sensor is depleted too severely to
use EasyCal
Sensor was not moved from buffer #1 to
buffer #2.
1. pH Standard value within 2 pH units
of Slope value
2. pH Sensor efficiency is inadequate
1. pH Slope value within 2 pH units of
Standard value
2. pH Sensor efficiency is inadequate
1. No temperature or mV signal from
sensor detected.
2. No connection between pH sensor
and preamplifier.
mV input is less than 0 pH or greater than
15 pH.
1. No temperature or mV signal from
sensor detected.
2. No connection between pH sensor
and preamplifier.
Suggested Solutions
1. Use pH 4, 7, 10 buffers
2. Clean probe and retry EASY CAL.
3. Use Manual calibration for Standard and
Slope if mV offset exceeds 50 mV.
1. Place sensor in correct buffer solution.
2. Use fresh buffer.
1. Use pH values at least 2 pH units apart.
2. Clean pH sensor; replace if necessary
3. Use fresh buffer.
1. Use pH values at least 2 pH units apart.
2. Clean pH sensor; replace if necessary
3. Use fresh buffer.
1. Check all wiring, contacts in preamplifier.
2. Verify sensor is securely installed.
3. Replace pH sensor.
1. Recalibrate system.
2. Replace pH sensor
3. Replace preamplifier.
1. Check all wiring, contacts in preamplifier.
2. Verify sensor is securely installed.
3. Replace pH sensor.
page 11 of 12
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