7
IV. MAINTENANCE
A.
Sensor
Maintenance
The turbidity sensor is designed to be easily removed, inspected, and cleaned when
required. It is recommended that the turbidity sensor be checked for fouling and cleaned
on a monthly basis. Heavily contaminated water may require more frequent cleanings.
Cleaner water sources with less contamination may not require cleaning for several
months.
B.
Sensor
Cleaning
Any equipment in contact with water treatment systems is subject to potential fouling and
contaminants. Sensors can be cleaned using cleaning solutions. A small, soft bristle
brush, Q-Tips cotton swab, or soft cloth may be used to safely clean the sensor housing
and the optical sensor channel.
To clean the sensor, soak the lower half of the sensor in 100 mL sensor cleaning solution
for 30 minutes. Rinse the sensor with distilled water and then check for the
fl
ashing blue
light inside the optical sensor channel. If the surface is not entirely clean, continue to
soak the sensor for an additional 30 minutes. Use a small, soft bristle brush and Q-Tips
cotton swabs as necessary to remove any remaining buildup in the sensors optical sensor
channel.
V. TROUBLESHOOTING
A. Installation Check – Review the following points
fi
rst.
Sensor Installation:
Check that the sensor head and
fl
ow cell are clean. Check that the
sensor is properly installed in the
fl
ow cell and that water is
fl
owing.
B. Symptoms, Likely Causes, and Suggested Responses
1.
Filter Time:
If the displayed reading is not stable, then the
fi
lter time can be increased
to eliminate this oscillation.
2.
Span Calibration:
If the span calibration is performed incorrectly, then this will cause
the readings to be inaccurate. Unless you intend to perform the span calibration, do not
touch the
and keys if you enter the span calibration screen.
3.
Sensor Wiring:
If the display is reading zero and giving an “Alarm Status: Error”
message, then the sensor may not be connected to the monitor. Check the wiring at the
circuit board in the monitor and inside the sensor enclosure.
4.
Sensor Replacement:
If the sensor is not putting out signals in the range of 4-20mA
on channels 1 and 2, then it may be damaged and require replacement. Contact Hydro
Instruments or your local sales representative.
5.
4-20 mA Output Calibration:
It is possible that somebody could enter the 4-20mA
output calibration screens and change the values without understanding their meaning.
This will cause the output 4-20mA signals to be inaccurate.
