Dwyer PUX - Manual (Page 83)

11 - 3
Eliminate entrance of air
bubbles.
• Raise the level of pump well.
• Confirm the shaft seal of
pump.
• Retighten the flange of
negative pressure piping.
• Prevent fluid from rushing
into pump well.
Move the sensor to the location
where air bubbles have not
entered.
• To the inlet side of pump
• To the upstream side of
valve
• Change the sensor mounting
method from V to Z.
• Move the sensor to the
location on the same line,
where the outer diameter of
pipe is smaller.
• Move to a different place or
different pipe.
• Raise the voltage for
transmission (refer to p.6-12).
Try measurement with the
optional large size sensor.
Contact Dwyer Instruments
Mount to a straight pipe.
• Minimize the cable between
main unit and sensors.
Mount the sensors in parallel
with the pipe following the
correct mounting dimension.
Bring the sensor in close contact
with the pipe.
Contact Dwyer Instruments
Air bubbles have entered.
In case measurement is normal
with water flow stopped, entrance
of air bubbles is the cause of this
error.
When the sensor is mounted just
after a valve, cavitation will occur
to cause the same effect as
entrance of air bubbles.
Turbidity is high.
Turbidity is higher than those of
sewage and return sludge.
Because of an old pipe, scale has
stuck to the inside.
Lining is thick.
Because of mortar lining or the
like, thickness is a few ten mm or
more.
Lining is peeled.
There is a gap between lining and
piping.
Sensor is mounted at a bent pipe
or tapered pipe.
3. Influence by external noise
• There is a radio broadcasting
station in the vicinity.
• Measurement has been
conducted near heavy traffic.
• Sensor mounting is incomplete.
• Mounting dimension is
improper.
• Sensor is not in contact with
pipe.
4. Hardware error
State Cause Remedy
BULLETIN F-68