4690 Series
Turbidity systems
9 Maintenance
34
IM/4690–EN Rev. A
9 Maintenance
The servicing schedule in Table 9.1 is a guide only. Because the
turbidity systems are designed for a wide range of applications,
where the nature of the sample can vary considerably, it may be
necessary to amend the schedule to suit the particular
installation and sample conditions.
9.1 Sensor Cleaning
9.1.1 Sensors Without Wiper Unit
These sensors are normally used on clean water samples and,
under normal conditions, may require only manual monthly
cleaning of the flow chamber. However, if a high turbidity
breakthrough occurs, clean the flow chamber immediately to
ensure accurate readings.
9.1.2 Sensors With Wiper Unit
The required automatic cleaning frequency of the flow chamber
and optical windows of the sensors can be determined only by
plant experience. It is recommended that checks are made at
appropriate intervals.
Task
Recommended Frequency
Wiper blade replacement
Quarterly
Light source (EPA 180.1)
replacement
Annually
LED light source (ISO 7027)
replacement kit
Every 5 years
Table 9.1 Suggested Maintenance Schedule
