Hach Flo-Dar, User Manual

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Maintenance
5.1 Preventative maintenance
Examine the Flo-Dar sensor on an annual basis to look for corrosion or damage that can
allow environmental gases into the interior. Make sure that no swelling, blistering, pitting
or loss of material has occurred on the upper and lower portions of the main plastic
enclosure, the depth module or the radome.
If the extended depth sensor is used, examine the enclosure and the four ¼-20 SS bolts.
If the surcharge velocity sensor (SVS) is used, make sure the unit is not corroded and the
labels are readable. Inspect the cable connectors for any damage or corrosion and
tighten all connectors in the system.
The only parts of the Flo-Dar system that can be replaced by the user are the bail
assembly and the cable. If the sensor becomes defective, it must be replaced as a
complete unit.
Check the electrical connections
Examine the cable connectors on an annual basis for corrosion and tightness. If
corrosion is found, clean and dry the connectors to make sure that no moisture is on the
connector pins. If corrosion is severe, replace the cables.
5.2 Cleaning the instrument
DANGER
Explosion hazard. Never attempt to wipe or clean the Flo-Dar or SVS sensor while
in a hazardous location. Do not use abrasives or high-pressure hoses or washers
to clean the sensors. Do not disturb the pressure port on the bottom of the sensor.
DANGER
Danger d'explosion. N'essayez jamais d'essuyer ou de nettoyer le Flo-Dar ou le
capteur SVS dans un emplacement dangereux. N'utilisez pas de produits abrasifs
ou de tuyaux sous pression ou d'appareils de nettoyage pour nettoyer les capteurs.
Ne dérangez pas le port sous pression situé dans le bas du capteur.
Regular cleaning is not necessary because the sensor does not contact the flow unless a
surcharge condition occurs. Examine the sensor after a surcharge to see if cleaning is
necessary.
Prerequisites
• Retrieval pole with hook (optional, see Accessories on page 37 ).
Procedure:
1. Remove power to the sensor.
2. Put the hook on the retrieval pole for removal without manhole entry. Make sure the
grounding strap is on the pole.
3. Hook the bail on the sensor and turn the pole counter-clockwise to unlock the sensor
from the frame. Remove the sensor.
4. Remove any debris from the bottom of the sensor. Clean the external surface of the
sensor with mild soap and rinse with water.
5. If the Surcharge Velocity Sensor (SVS) is used, use 600 grit sand paper to lightly
sand the electrodes (small black dots). Use only light pressure when sanding or the
electrodes will become damaged.
6. Lower and position the sensor on the frame. Make sure that the cable points toward
the center of the manhole.
7. Turn the retrieval pole clockwise to engage the locking bars into the frame.
8. Apply power to the sensor.