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< 8. Maintenance >
8-1
IM 12F5A1-01E
8. INSPECTION AND MAINTENANCE
This chapter describes the inspection and maintenance required to maintain the FC400G
operation in good condition.
8.1 Inspection and Maintenance Items and
Implementation Cycle
The table below shows the principal inspection and maintenance items and recommended
maintenance intervals to maintain good operating condition.
Actual maintenance intervals must be determined in accordance with individual operating
conditions.
Table 8.1 Inspection and Maintenance Items and Implementation Cycle
Inspection and Maintenance Items Implementation Cycle
● P olishing of indicator electrode
● Replacement of indicator electrode
● Ceramic beads cleaning
● Replacement of ceramic beads
● Measuring tank cleaning
● Calibration
● Replacement of activated charcoal filter
Monthly
Once a year
Every 3 months
Once a year
Every 3 months
Monthly
Once a year
Note: Appropriate maintenance intervals must be determined in accordance with the condition or contamination. Same applies (to
decrease of influence of) combined chlorine insensitive version with gold alloy electrode and glass beads.
8.1.1 Polishing the Indicator Electrode
The indicator electrode constantly rotates at 600 rpm (at 50 Hz) and is automatically continuously
polished with ceramic beads. However, this does not completely prevent adhesion of
contamination; contamination gradually accumulates on the electrode surface over time.
A contaminated electrode surface is a cause of measurement error. The degree of this
measurement error increases depending on the amount of contamination. Therefore, the
electrode surface must be polished using abrasive (alumina) to remove such contamination
before measurement error exceeds the allowance.
Polishing frequency differs with the quality of the sample water. Polishing every a few months
may be sufficient in some cases. However, in general, it is recommended that the indicator
electrode be polished every month. For polishing procedure, follow
Sec. 6.1.4
, when the electrode
is polished, zero point and span must always be calibrated.
While the indicator electrode rotates at 600 rpm (at 50 Hz), the electrode is automatically polished
with ceramic beads. However, this does not completely prevent adhesion of contamination;
contamination gradually accumulates on the electrode surface over time. Therefore, the
electrode surface must be polished manually with polishing powder (alumina) to remove
such contamination before the measurement error exceeds the allowance. For the polishing
procedure, follow Sec. 6.1.4. In particular, polish the electrode surface as described when it has
become corrugated or deformed from the original shape (circle with a diameter of about 3 mm).
Note: It is recommended to polish the indicator electrode every month. Every two or three months
may be sufficient in some cases; the required polishing frequency differs with the quality of
the sampling water. After polishing the electrode surface, conduct calibration with running-in
operation.
(1) Press the
MODE
key on the converter to enter the operation level and press the
YES
NO
key to select the <CELL> mode (cell motor ON / OFF). Press the
NO
key with
respect to the message “CELL ON” displayed to stop the rotation of the indicator electrode.
When the electrode stops rotating, the CELL lamp extinguishes.
Remove the electrode mechanism block from the measuring tank and set up the block as