28
6.0 Maintenance
The WDIS control module itself needs very little maintenance. Clean the outside of the controller
enclosure with a damp cloth. Do not spray down the controller unless the enclosure door is closed and
latched. "Pigtails" should be protected from spray or wash-down. Check the cords and cables for
damage.
6.1 Sensor
Maintenance
Cleaning the Membrane
Instructions for cleaning the membrane vary depending upon the type of contamination. Follow the
directions for replacing the membrane shown below, replacing step 3 with one of these cleaning
methods:
For general deposits:
Rinse in clear cold water.
For calcium scale:
Soak in dilute (1% by volume) hydrochloric acid, then rinse in clear cold water.
For oils:
Rinse in isopropyl alcohol.
DO NOT use cleaners or detergents containing surfactants, as these will reduce the life of the
membrane.
If the sensor still cannot be calibrated after cleaning, replace the membrane cap as described below.
Replacing the Membrane
CAUTION: Wear gloves and safety glasses during assembly of the sensor since the electrolyte is a
STRONG ACID. It is recommended to perform this operation over a sink with running water
available. After using, re-cap any remaining electrolyte until the next use.
1. Hold the sensor vertically with the membrane facing down and carefully unscrew the membrane cap.
Always move the gray bands to uncover the vent hole before removing the cap!
2. Rinse the electrolyte fill solution off the cap and electrodes with cold water.
3. Discard the old membrane cap.
4. Unpack the new membrane cap, taking care not to touch the membrane or get it dirty.
5. Fill the membrane cap to the top with the electrolyte fill solution.
6. Hold the sensor body vertically with the tip pointing down and SLOWLY screw on the membrane
cap until it is hand tight.
Be prepared for some electrolyte solution to squeeze out from the cap
7. Rinse your hands, the sensor, and all surfaces contaminated with electrolyte solution with running
water.
8. Check the sensor for leaks, especially at the membrane and the membrane cap threads. If any leaks
are detected, tighten the membrane cap or replace it.
