Hach 911, User Manual

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63
Maintenance
7.8.4 Changing the Submerged Area/Velocity Sensor Desiccant
The desiccant canister contains beads of silica gel which ensure proper orientation of the
pressure transducer. When the beads are blue, they can remove moisture from the air.
When they are pink, they are saturated and cannot absorb any more moisture from the air,
and they must be replaced immediately.
Important Note: When the beads begin to turn pink, replace or recondition the beads.
Permanent damage to the sensor may occur if the desiccant is not maintained. Never
operate the sensor without the proper desiccant. When rejuvenating beads, remove them
from the canister and heat at 100–180 °C (212–350 °F) until the beads turn blue. If the
beads do not turn blue, replace them with new beads. Do not heat the canister.
Figure 36 Attaching the Feed Tube and Syringe
Figure 37 Oil Replenishment
1 Sensor 3 Side port
2 Set screw 4 Syringe