HYDROSENSE HS2410
Revision 5.0
P a g e 26 | 27
11.0 PERIODIC
TESTING
AND
MAINTENANCE
NOTICE
Calibration must be performed after installation and any lamp replacemnt.
11.1 PERIODIC
TESTING
The HydroSense is an electronic device used for environmental and personal protection, as well as
general process monitoring. As with any calibrated sensing device, wetted parts may become
contaminated and the light source can deteriorate over time. The Arjay system has a Maintenance
alarm (R3) feature and a fault alarm (R4) included, however, a scheduled periodic test is recommended
to ensure that the unit and remote alarms and devices are operating to specifications.
A flow plate is used for all applications and is shipped as the standard with the unit. Film build-up of
algae and silt will not affect the operation of the unit unless it accumulates oil from contaminated water
to a point at which the unit acknowledges and reads this oil. It is suggested that routine maintenance be
scheduled to verify that this build-up is not extreme and the flow plate is cleaned as necessary.
There are three standard tests to assure the operation and accuracy of this unit.
The first is a BUMP TEST. To confirm that the unit is responding to the contaminant, a higher or lower
concentration than normal may be manually inserted into the stream at the actual process or at the
sample chamber.
Divert the 3 way valve and provide clean water or a different concentration sample into the flow.
Observe that the reading increases or decreases and alarms accordingly.
A second test is a FLUORESCENCE ACCURACY TEST. The clear flow plate provided with the unit
can be used to confirm the response to fluorescence of the unit. After a calibration has been completed,
lift the Lamp box to access the flow plate. Turn off the inlet water and flip the flow plate with the etched
“UP” now facing down. Leave the water off. Secure the lamp box back in position and close the
chamber door. Read and record the display in PPM for future reference . Periodically, or in conjunction
with the BUMP TEST, insert this flow plate upside down and confirm that the reading is within 5% of the
initial reading. If the unit is not within specification, re-calibration of the unit should be initiated.
IMPORTANT: Each time the unit is re-calibrated, the flow plate should be inserted upside down and
the new reading recorded.
NOTICE
After bump test is preformed the glass flow plate must be place in the
“UP” position for normal operation.
It is recommended that the above tests be done initially with a high frequency to record a history of the
unit stability. The frequency can be reduced to a level comfortable to the application and customer. A
one month minimum check is recommended in conjunction with a flow plate cleaning.
A third test is an actual CALIBRATED SAMPLE TEST. Since the two above tests confirm both a
response to a calibrated sample flow plate and the contaminant, using an actual sample may only be
necessary in applications where precise data records and monitoring is required. To test the accuracy
and calibration of the unit, have a sample analyzed by a lab and compare it to the observed reading.
The lab procedures must be the same as the ones used for calibration.
NOTICE
Any sample sent to a lab may incur separation and evaporation during
transit. Advise the lab to thoroughly mix the sample prior to testing.