YOKOGAWA FC500G, User Manual, Page: 28 / 41

<6. INSPECTION AND MAINTENANCE>
6-1
IM 12F5A2-01E
6. INSPECTION AND MAINTENANCE
To continue good operating status, perform inspections and maintenance as shown in Table 6.1.
Determine the implementation cycle in accordance with the individual operation conditions. Table
6.1 is a guide for the implementation cycle.
Table 6.1 Inspection and Maintenance Items and Implementation Cycle
Inspection and maintenance item Implementation cycle
Indicator electrode polishing Once/month
Glass beads cleaning Once/three months
Measuring tank cleaning Once/three months
Inspection or brush and slip ring Once/three months
Calibration Once/month
Converter checking Once/month
Fuse replacement Once/year
6.1 Mechanical System
6.1.1 Indicator Electrode Polishing
Indicator electrode contamination influences the measured values. Accordingly, the indicator
electrode (rotating electrode) is always rotated to polish its surface using glass beads.
However, the surface very gradually becomes contaminated with time elapse. Thus, periodically
polish the electrode surface using a polisher (alumina).
Polish the electrode surface using the following procedure:
(1) Remove the converter cover and turn OFF the converter power switch.
(2) Remove the electrode assembly from the measuring tank and fix it to the holding stud. It is
not necessary to stop the sample water.
(3) Remove the electrode assembly cover.
(4) Insert an Allen wrench (accessories) into the hole on the side of the rotating shaft below the
drive belt and manually fix the shaft. Remove the indicator electrode by turning it counter-
clockwise. Do not touch the rotating shaft brush, slip ring, or the indicator electrode surface.
(5) Apply polisher (alumina) attached as an accessory to a wet gauze and carefully polish the
electrode surface until all contamination is completely removed. After polishing, wash off the
polisher using clean water. Once the surface is clean, it will wet uniformly without repelling
water.
F6-1.ai
Electrode surface
Figure 6.1 Indicator (Rotating) Electrode
(6) Similar to electrode removal, insert an Allen wrench into the hole and manually fix the
rotating shaft so that it does not turn. Fully screw in the indicator electrode (turn clockwise).