
IM-P505-02-US
Issue 1
80
UTM20 Series Ultrasonic Transit-time Flowmeters
11.6 Symptoms
Symptom: Transmitter does not power up.
Possible
Causes
No power or inadequate power
Blown fuse (AC Model only)
Display ribbon cable not seated properly
Recommended
Action
Measure voltage at the power terminals and check that the voltage matches the labels by the
power terminals
Check the fuse near the power terminals If fuse is blown, verify the voltage and polarity is correct
and reset the fuse
Inspect ribbon cable connections LED’s on power board will light up with no LCD display
Replace the transmitter if the above actions do not resolve the issue
Symptom: Flow reading appears to be incorrect.
Possible
Causes
Incorrect positioning of transducers
Poor contact between transducers and pipe
Poor placement of transducers
Low signal strength
Process loop issues
Incorrect pipe settings
Meter not calibrated
Display not set up correctly
Recommended
Action
Refer to the Transducer Mounting Configuration section for details on proper installation
At the transducer:
Verify that the spacing of the transducers is set correctly On most transducers, a scribe mark on the
side of the transducers indicates the point of measurement—NOT from the end points of the transducers
Verify that the transducers are aligned correctly For Z-Mount, verify the transducers are 180° From
each other
Make sure there is a good contact between the transducers and pipe and a thin coat of acoustic
coupling is applied For integral mount, check for over-tightening of the transducers
Process loop and general location:
Make sure the transducers are on the sides of the pipe and NOT on the top of the pipe
Check that the transducers are NOT located at the highest point in the loop where air may accumulate
Check that the transducers are NOT on a downward flowing pipe unless adequate downstream head
pressure is present to overcome partial filling or cavitation
Check that the transducers have adequate straight pipe upstream and downstream
Check process loop for entrained air or particulates which will impact the flow readings
Pipes may develop scale, product build-up or corrosion over time As a result, the effective wall thickness
may be different than a new pipe and wall thickness or liner parameters may need to be adjusted
At the transmitter:
Verify that pipe parameters match the installation