Hach D3433B8.99, User Manual

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5.1 Clean the sensor
Pre-requisite: Prepare a mild soap solution with warm water and dishwashing detergent, Borax
hand soap or a similar soap.
Examine the sensor periodically for debris and deposits. Clean the sensor when there is a buildup of
deposits or when performance has degraded.
1. Use a clean, soft cloth to remove loose debris from the end of the sensor. Rinse the sensor with
clean, warm water.
2. Soak the sensor for 2 to 3 minutes in the soap solution.
3. Use a soft bristle brush to scrub the entire measuring end of the sensor.
4. If debris remains, soak the measuring end of the sensor in a dilute acid solution such as < 5%
HCl for a maximum of 5 minutes.
5. Rinse the sensor with water and then return to the soap solution for 2 to 3 minutes.
6. Rinse the sensor with clean water.
Always calibrate the sensor after maintenance procedures are done.
Section 6 Troubleshooting
6.1 Intermittent data
During calibration, data is not sent to the datalog. Thus, the datalog can have areas where the data is
intermittent.
6.2 Test the conductivity sensor
If a calibration fails, first complete the maintenance procedures in Maintenance on page 13.
1. Disconnect the sensor wires.
2. Use an ohmmeter to test the resistance between the sensor wires as shown in Table 3 .
Note: Be sure that the ohmmeter is set to its highest range for all infinite (open circuit) resistance readings.
Table 3 Conductivity resistance measurements
Measurement points Resistance
Between blue and white wires 1089–1106 ohms at 23–27 °C
Between red wire and sensor body Less than 5 ohms
Between black wire and inner electrode Less than 5 ohms
Between black and red wires Infinite (open circuit)
Between black and white wires Infinite (open circuit)
Between red and white wires Infinite (open circuit)
Between red and inner shield wires Infinite (open circuit)
Between black and inner shield wires Infinite (open circuit)
Between white and inner shield wires Infinite (open circuit)
Between outer and inner shield wires Infinite (open circuit)
If one or more of the measurements is incorrect, call technical support. Supply technical support with
the serial number of the sensor and the resistance values measured.
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