6.2 Avoiding freezing conditions
Expansion of water due to freezing will irreparably damage the CRS451/CRS456. The
CRS451/CRS456 can be safely deployed in freezing conditions if the sensor is placed below the
frost line. In a lake or channel of moving water, often the sensor can be placed deep enough to
avoid freezing. In shallow conditions, where the water body is at risk of freezing solid, placing the
sensor in a stilling well that extends below the frost line will protect the sensor from freezing
water.
6.3 Dislodge bubbles
While submersing the CRS451/CRS456, air bubbles may become trapped inside the nose cone,
causing small, offset errors until the bubbles dissolve. Dislodge these bubbles by gently shaking
the CRS451/CRS456 while under water.
CAUTION:
Hitting the instrument against the well casing or other solid surface could damage the
CRS451/CRS456.
CAUTION:
If the bubbles are not removed by rotation and shaking underwater (or bleeding out the air
in a closed system), the CRS451/CRS456 reading will drift lower by the distance of the gap as
the air is slowly dissolved into the water over time.
6.4 Well installation
Campbell Scientific offers a braided stainless steel cable to lower the instrument to an
appropriate depth and to suspend the CRS451/CRS456 in a well.
With long drops, it may be necessary to use the weighted nose cone (option –WN).
For surface installations, the instrument body can be strapped with tie wraps or tape. Campbell
Scientific offers cable ties to secure the cable. If installing in a well, fasten the cable to the well
head.
6.5 Other installations
The CRS451/CRS456 can be installed in any position; however, when it leaves the factory it is
tested in the vertical position. There will be an offset error if not installed vertically; contact
CRS451/CRS456 Submersible Water-Level Recording Sensor
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