Maintenance; Frequently, If Necessary - Hach LDO AQS sensors User Manual

Table 3 Salinity (PSU) per conductivity value (mS/cm) (continued)
mS/cm PSU
8 5
9 6
10 6
11 7
12 8
13 8
14 9
15 10

Maintenance

Multiple hazards. Only qualified personnel must conduct the tasks described in this section of the
document.
Maintenance schedule
The maintenance schedule shows minimum intervals for regular maintenance tasks. Perform
maintenance tasks more frequently for applications that cause electrode fouling.
Note: Do not disassemble the probe for maintenance or cleaning.
Maintenance task
Clean the sensor
Inspect the sensor for damage
Replace the sensor cap
Clean the sensor
Clean the exterior of the sensor with a soft, wet cloth.
Note: If the sensor cap must be removed for cleaning, do not expose the interior of the cap to direct sunlight for
extended periods of time.
Change the sensor cap
Potential explosion hazard. The sensor setup cap is not rated for hazardous location use.
Replacement sensor caps and setup caps are shipped with installation instructions. Refer to the
included instructions to change the cap. After the new sensor cap is installed, make sure that the lot
number on the sensor cap is the same lot number that is read by Modbus. The sensor uses the
calibration information from the sensor cap.
For best performance and accuracy, replace the sensor cap:
• Every two years, or more frequently if necessary
• When routine inspection shows significant erosion of the sensor cap
mS/cm PSU
19 13
20 13
21 14
22 15
23 15
24 17
25 17
26 18
W A R N I N G
W A R N I N G
mS/cm PSU
30 21
31 22
32 22
33 23
34 24
35 25
36 25
37 26
Recommended minimum frequency
90 days
90 days
2 years or more frequently, if necessary
mS/cm PSU
42 30
44 32
46 33
48 35
50 37
52 38
54 40
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