Hach-Lange 9187 sc - Manual (Page 29)

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Section 5 Maintenance
DANGER
Only qualified personnel should conduct the tasks described in this section of the
manual.
5.1 Maintenance Schedule
The following schedule shows the minimum maintenance requirements for typical
operation.
5.2 Scheduled Maintenance
CAUTION
To familiarize yourself with handling precautions, dangers and emergency
procedures, always review the Material Safety Data Sheets prior to handling
containers, reservoirs, and delivery systems that contain chemical reagents and
standards. Protective eye wear is always recommended when contact with
chemicals is possible.
5.2.1 Replacing the Membrane
Note: When removing the probe from the sample, we recommend keeping the probe vertical with
the membrane facing down. Avoid touching the active part of the membrane.
Replace the membrane every 6 months under typical operating conditions, or more
frequently as experience dictates (
Figure 12 ).
1. Shut off the sample supply. Remove the probe cable.
2. Unscrew the probe retaining ring. Remove the sensor.
Note: Removing the sensor may activate alarms. Ensure that removing the sensor will not affect
plant operation by switching to maintenance mode.
3. Unscrew the electrode retaining ring and filling screw.
Note: Never pull sharply on the electrode when the filling screw is in place.
4. Remove the electrode. Pour out the electrolyte.
5. Unscrew the membrane.
Note: Do not re-install a used membrane. After changing the membrane, allow the probe to stabilize
for at least three hours; recalibrate the sensor.
For re-assembly, see section 3.5.1 on page 11 .
Maintenance Task 2 Months 3 Months 6 Months Annually
Membrane X
Electrolyte X
pH (9184sc only) X
Cleaning 1 X
Tubing X
Calibration X
1 Maintenance frequency is application dependent. Additional or less maintenance will be appropriate in some applications. The
sensor must be cleaned before liquid standard verification or calibration.