Hach Flo-Dar, Basic User Manual

Page: 27 / 286

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 on the electrodes (small
black dots). Use only light pressure or the electrodes will become damaged.
6. Lower 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.
7.3 Replace a cable
If corrosion is severe on a connector(s) or a cable has damage, replace the cable.
1. Disconnect power to the sensor at the logger or controller.
2. Put the hook on the retrieval pole to remove the sensor without manhole entry. Make sure that
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 the two Phillips screws on the sensor handle to remove the cable clamp. Remove the
cable.
5. Install the new cable. Make sure that the connector is aligned correctly and that no debris or
water gets into the connector.
6. Install the cable clamp.
7. Lower the sensor on the frame. Make sure that the cable points toward the center of the manhole.
8. Turn the retrieval pole clockwise to engage the locking bars into the frame.
9. Apply power to the sensor through the logger or controller.
7.4 Replace the desiccant
C A U T I O N
Chemical exposure hazard. Obey laboratory safety procedures and wear all of the personal protective
equipment appropriate to the chemicals that are handled. Refer to the current safety data sheets
(MSDS/SDS) for safety protocols.
C A U T I O N
Chemical exposure hazard. Dispose of chemicals and wastes in accordance with local, regional and
national regulations.
N O T I C E
Do not operate the sensor without desiccant beads or with green desiccant beads. Permanent damage to the
sensor can occur.
Immediately replace the desiccant when it changes to green. Refer to Figure 21 .
Note: It is not necessary to remove the desiccant container from the desiccant hub to install new desiccant.
At step 5 of Figure 21 , make sure that the O-ring is clean and has no dirt or debris. Examine the O-
ring for cracking, pits or sign of damage. Replace the O-ring if it has damage. Apply grease to dry or
new O-rings to make installation easier, to get a better seal and to increase the life of the O-ring.
For the best performance, make sure to install the desiccant container vertically with the end cap
pointed down. Refer to
Attach the desiccant hub (FL900) on page 25.
Note: When the beads just begin to turn green, it may be possible to rejuvenate them by heating. Remove the
beads from the canister and heat them at 100-180 ºC (212-350 ºF) until they turn orange. Do not heat the canister.
If the beads do not turn orange, they must be replaced with new desiccant.
English 27