MODEL | SECTION 9.0 |
| TROUBLESHOOTING |
9.4.6Sensor Temperature High or Low The sensor RTD is most likely miswired.
1.Check wiring connections.
2.Check resistance between RTD in and return leads. The resistance should be close to the values given in Section 9.10.2.
3.Replace sensor.
9.4.7 Broken Glass Disabled
The impedance of the pH glass electrode is a strong function of temperature. As temperature increases, the glass impedance decreases. Because the broken glass fault message appears when the glass impedance becomes too low, it is important that low impedance readings be properly corrected for temperature effects. However, there is a high temperature cutoff beyond which the correction does not work. Once the temperature exceeds this value, the broken glass fault is automatically disabled.
This warning should never appear in the
9.5 TROUBLESHOOTING WHEN NO ERROR MESSAGE IS SHOWING — CHLORINE
| Problem | See Section | |
| Zero current was accepted, but the current is substantially greater than 10 nA | 9.5.1 |
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| Error or warning message appears while zeroing the sensor (zero current is too high) | 9.5.1 |
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| Zero current is unstable | 9.5.2 |
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| Sensor can be calibrated, but sensitivity is significantly different from 350 nA/ppm | 9.5.3 |
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| Process readings are erratic | 9.5.4 |
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| Readings drift | 9.5.5 |
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| Sensor does not respond to changes in chlorine level | 9.5.6 |
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| Chlorine reading spikes following rapid change in pH | 9.5.7 |
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9.5.1 Zero current is too high
1.Is the sensor properly wired to the analyzer? See Section 3.2.
2.Is the zero solution
3.Has adequate time been allowed for the sensor to reach a minimum stable residual current? It may take several hours, sometimes as long as overnight, for a new sensor to stabilize.
4.Check the membrane for damage and replace it if necessary.
9.5.2 Zero current is unstable
1.Is the sensor properly wired to the analyzer? See Section 3.2. Verify that all wiring connections are tight.
2.Readings are often erratic when a new or rebuilt sensor is first placed in service. Readings usually stabilize after about an hour.
3.Is the conductivity of the zero solution greater than 50 µS/cm? DO NOT USE DEIONIZED OR DISTILLED WATER TO ZERO THE SENSOR. The zero solution should contain at least 0.5 grams of sodium chloride per liter.
4.Is the space between the membrane and cathode filled with electrolyte solution and is the flow path between the electrolyte reservoir and membrane clear? Often the flow of electrolyte can be started by simply holding the sensor with the membrane end pointing down and sharply shaking the sensor a few times as though shaking down a clinical thermometer. If shaking does not work, try clearing the holes around the cathode stem. Hold the sensor with the membrane end pointing up. Unscrew the membrane retainer and remove the membrane assembly. Be sure the wood ring remains with the membrane assembly. Use the end of a straightened paper clip to clear the holes at the base of the cathode stem. Replace the membrane.
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