Hach AV9000S User Manual page 18

Replace the hydrophobic membrane
Replace the hydrophobic membrane when:
• Unexpected increases or decreases in level trends occur.
• Level data is missing or incorrect, but the velocity data is valid.
• The membrane is torn or has become saturated with water or grease.
Refer to the illustrated steps that follow to replace the membrane. At step 4, make sure that the
following occurs:
• The smooth side of the hydrophobic membrane is against the inner surface of the desiccant
container.
• The hydrophobic membrane bends up and goes fully into the thread until it is not seen.
• The hydrophobic membrane turns with the nipple when the nipple in the desiccant container turns.
If the membrane does not turn, it has damage. Start the procedure again with a new membrane.
For the best performance, make sure to install the desiccant container vertically with the end cap
pointed down. Refer to
18 English
Attach the desiccant hub on page 8.