Replace The Desiccant Pack - Hach WPC-21 Manual Del Usuario

5. Connect the sample line to the compression fitting on top of the sensor assembly.
6. Start the flow of water to the instrument. After 30 seconds, stop the flow.
7. Remove the sample line from the compression fitting.
8. Clean the sensor flow cell.
a. Pour clean water into the compression fitting on top of the sensor assembly. The water will
drain from the sample line compression fitting.
b. Insert the cleaning brush into the compression fitting. Gently move the brush up and down two
or three times. Refer to
c. Pour clean water into the compression fitting on top of the sensor assembly. This will rinse out
any material that was loosened by the brush.
d. Pour clean water over the cleaning brush to rinse out any material.
9. Connect the sample line and drain line tubing. Refer to
10. Start the flow of water to the instrument.
11. Set the power switch to on.
12. Close the enclosure door. Tighten all four captive screws that attach the enclosure door.
Figure 10 Clean the sensor flow cell

Replace the desiccant pack

Replace the desiccant pack when the color of the crystals in the desiccant pack change from blue to
pink. Refer to Figure 1
A desiccant pack must be used to prevent moisture build up in the instrument enclosure. This will
help prevent corrosion of sensitive electrical connections and help prevent the collection of
condensation in the sensor assembly.
Items to collect:
• Desiccant pack
• Velcro adhesive strip
1. Open the enclosure door. Loosen all four captive screws that attach the enclosure door.
2. Set the power switch to off.
3. Open the electrical access panel. Turn the two ¼-turn captive screws only ¼ turn.
4. Replace the desiccant pack.
a. Pull the used desiccant pack off the Velcro strip on the rear panel and discard.
b. Put an adhesive Velcro strip on a new desiccant pack.
c. Push the desiccant pack on the Velcro strip on the rear panel.
20 English
Figure 10.
on page 7 for the location of the desiccant pack.
Plumb the instrument on page 13.