Troubleshooting - Hach NX7500 Manual Del Usuario

The measuring window is made of quartz glass. Rinse the measuring window with tap water to
remove particles. Then, clean the measuring window with a few drops of acetone and a lint-free
cloth.
To remove a thin layer at the windows, use a soft cloth or clean water. Do not use harsh cleaning
solutions, spatula, sand paper or cleaning products with abrasive ingredients to remove continuous
dirt. Contact the manufacturer to replace damaged windows.
Note: Do not scratch the glass of the windows.
Note: Make sure not to touch the window surface with fingers.
1. From the Main menu, select Options.
2. Select Service mode to set the relay for the compressed air cleaning on HOLD.
Note: The Service mode also disables measurements.
3. Remove the sensor from the basin or flow cell.
4. Clean the measuring window with a cleaning agent and a cloth.
5. When the cleaning is complete, push Service mode to remove the HOLD condition.
Clean the compressed air connector
1. Manually clean the compressed air connector 1–2 times a week.
2. Clean the compressed air connector if very fine mud clogs the cleaning connector.
To prevent blockages, install a check valve.

Troubleshooting

Disconnect the compressed air cleaning system before the sensor is removed from the basin.
Problem
The controller cannot
find the sensor.
The sensor readings
are much higher or
lower than expected.
16 English
Solution
Examine the cable and the probe connector for damage. Contact the technical support if
there are damages.
1. Make sure that settings for factor and offset are correct. Refer to
on page 14.
2. Identify the expected measuring value is measurable with the installed optical path
length.
3. Measure the optical path length of the sensor. Make sure that the correct length is set
in the controller settings. Refer to the controller documentation for more information.
4. Clean the measuring windows. Refer to
5. Put the sensor in a container with a known target parameter concentration (sample or
standard). Make sure that there are no air bubbles between the measuring windows.
Use a syringe to put sample between the measuring windows.
• If the readings are correct—There is an issue with dirt or air bubbles blocking the
optical path in the application. Change the location or the cleaning settings.
Contact the technical support.
• If the readings are not correct—Contact the technical support.
Clean the measuring window
Calibrate the sensor
on page 15.