Campbell Scientific CS451/CS456 Pressure Transducer - Manual (Page 29)

CS451/CS456 Submersible Pressure Transducer
Problem:
Transducer appears to be operating properly but data shows a periodic or cyclic
fluctuation not attributable to water level changes.
Suggestion:
A kinked or plugged vent tube will not effectively vent a gauge pressure
(Vented) type of device. Normal changes in barometric pressure will appear as
water level fluctuations and these types of errors are typically on the order of 1
foot of water level. If the desiccant chamber has not been properly maintained,
water may have condensed in the vent tube and the device should be returned
to the factory for service.
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