-93-
Status Probable cause Troubleshooting
(Continued from the
previous page.)
High turbidity
Turbidity is higher than those of
sewage and return sludge.
Move sensor to a place of smaller
diameter on the same pipeline.
Move the sensor to other places or to
different piping.
Pipe is old and scale is attached
on inside.
Lining is thick.
Because of mortar lining or the
like, thickness is tens mm or
more.
Lining is peeled.
There is a gap between the lining
and the pipe.
Sensor is mounted on bend pipe
or tapered pipe.
Mount the sensor on straight pipe.
3. Effect of external noise
Reduce the length of main unit
sensor cable to a minimum.
Ground the main unit and piping.
There is a radio broadcasting
station nearby.
Measurement conducted near
a passage of vehicles or
electric cars.
4. Hard failure
Refer to “6.5.7. Remedying a hardware
fault”.
Measured value not zero
when fluid stops flowing.
Fluid forms a convection inside
the pipe.
Normal
Zero point adjustment
Readjust the zero point after fluid has
completely stopped flowing.
Pipe is not completely filled or is
empty when water is at a
standstill (LED lit red).
Normal
Error in measured value
Input piping specifications differ
from the actual ones.
A difference of 1% in inner diameter
causes an error of about 3%.
Input the correct specifications.
Input scale as lining.
Scales exist on wall of old pipe.
Insufficient linear pipe length
(10D or more for upstream and
50D or more for downstream)
Find another mounting place (upstream
of disturbing objects).
No disturbing objects in flow within 30D
upstream without pump, valve,
combined pipe, etc.
Mount the sensor at different angles
with respect to the cross section of
pipe to fine the location where mean
value is obtainable. The mount the
sensor at that location.
Pipe is not filled with fluid or
sludge is deposited in the pipe.
Occurs particularly where sectional
area is small.
Move sensor to a vertical pipe.
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