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| PROBLEM |
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POSSIBLE CAUSE |
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SOLUTION |
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| Calibration Fail (CF) |
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Faulty Solenoid Valve |
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Run Solenoid Check cycle in Diagnostics – check status and connections of solenoid valve. Verify operation of valve by removing sensor from flowcell and perform another CAL with sensor exposed to atmosphere. |
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| Calibration Fail (CF) |
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POOR (low) sensor output. |
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Check probe handle assembly connection and other connections to sensor. |
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| Calibration Fail (CF) |
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POOR (high) sensor output. |
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New sensor – needs to rinse down. Let sensor run on sample for 1 hour – repeat calibration. |
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| Calibration Fail (CF) |
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POOR (low) sensor output. |
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Old/bad sensor. Replace sensor. |
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| Readings are not accurate – too low. |
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Poor sensor performance. Bad calibration. Bad thermistor. |
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Replace sensor. Check CAL log and run another CAL if last result is not good. Verify temperature as indicated on analyzer. |
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| Readings are not accurate – too high. |
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Poor sensor performance. Bad calibration. Dissolved Oxygen leak in sample system. Bad thermistor. |
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Let sensor run on sample water for 1-2 hours; then run another CAL. Replace sensor. Check CAL log and run another CAL if results are not good. Bench test sample water. Check temperature. |
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| Readings are not accurate – too high |
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Defective probe handle assembly. Moisture in probe handle assembly. |
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Measure resistance of probe handle assembly. Verify there is no voltage (mV) generated by a galvanic reaction in handle assembly. |
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| Readings are not accurate – too low |
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Defective probe handle assembly. High resistance in assembly or corrosion on mating pins. |
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Replace probe handle assembly. |
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| Current outputs (4-20mA) not functioning correctly. |
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Disconnected wiring at transmitter or along wire path. DCS/recording system not set up properly. Bad CPU board. |
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Check output set-up to make sure values are entered properly. Run Diagnostics – O/Pma Check cycle and check output coming from transmitter. Replace CPU board. |
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| Alarms not functioning correctly. |
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Disconnected wiring at transmitter or along wire path. DCS/recording system not set up properly. Bad DIO board. |
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Check alarm set-up to make sure values are entered properly. Run Diagnostics – Relay Check cycle and check alarm output directly from transmitter. Replace DIO board if output is not correct. |
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| Display read “HOT” |
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Sample temperature over specified range (>131F). Faulty thermistor. |
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Check sample temperature. Clean/replace thermistor. |
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| Display read “TEMP” |
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No thermistor response. |
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Clean/replace thermistor. Check thermistor connection on card. |
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| Display read “OVR” |
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Signal from sensor too high – sample concentration over maximum range (>20ppm) |
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Check sample concentration. Check sensor connections. |
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