Vortex flow meters operate based on the Kármán vortex shedding principle.
When fluid flows past a bluff body (vortex shedder), alternating vortices are generated downstream. The shedding frequency is directly proportional to the fluid velocity, allowing accurate flow measurement.
Although vortex flow meters are widely used for steam, gas, and liquid flow measurement, some common faults may occur during operation.
This guide summarizes the most common problems, possible causes, and troubleshooting solutions.
1. No Flow Display (Output Signal = 0 or Fixed Value)
This is one of the most common issues in field applications.
Possible Causes
Power Supply Failure
- 24VDC power interruption
- fuse blown
- reverse polarity wiring
Typical symptom:
No display on the transmitter, output remains at 0 mA.
Sensor and Converter Connection Failure
- broken signal cable
- loose terminals
- poor shield grounding
Typical symptom:
The converter receives no input signal and shows zero flow.
Vortex Shedder or Sensor Probe Blockage
Particles, fibers, or sludge may accumulate around the bluff body or sensor probe.
Typical symptom:
Fluid is flowing but no signal is detected.
Transmitter Damage
Internal electronic components such as:
- amplifier circuit
- frequency converter module
may fail.
Typical symptom:
Power supply is normal but no output signal.
2. Unstable Flow Reading (Fluctuating Signal)
If the reading jumps up and down, the issue is usually related to the flow condition.
Disturbed Flow Profile
Insufficient straight pipe length upstream is the most common reason.
Recommended:
- upstream ≥ 10D
- downstream ≥ 5D
Disturbance sources include:
- elbows
- valves
- pumps
- reducers
Typical symptom:
Reading fluctuation synchronized with pipeline vibration.
Two-Phase Flow / Air Bubbles / Condensate
For steam service:
- condensate water may be present
For liquid service:
- air bubbles may enter the pipeline
This causes unstable vortex frequency.
Typical symptom:
Signal fluctuation changes with process pressure or temperature.
Incorrect Installation
If the sensor is not centered or installed at an angle, vortex detection becomes unstable.
Typical symptom:
More obvious fluctuation at low flow rates.
Electromagnetic Interference
Nearby equipment such as:
- motors
- inverters
- VFD drives
can interfere with the pulse signal.
Typical symptom:
Random fluctuation with no process correlation.
3. Flow Reading Too High or Too Low
Wrong Parameter Settings
Common wrong settings include:
- pipe size
- medium density
- flow range
- K-factor
For example, if the actual pipe size is DN100 but set as DN80, the reading will be significantly higher.
Sensor Sensitivity Decrease
Over time, the sensor element may age or corrode.
Typical symptom:
Measurement deviation gradually increases.
Vortex Shedder Wear
Long-term erosion by steam, gas, or slurry may wear the bluff body edge.
Typical symptom:
Reading continuously lower than actual flow.
Flow Velocity Out of Range
Typical recommended velocity:
- liquid: 0.5–8 m/s
- steam / gas: 5–25 m/s
If the velocity is too low, the vortex signal becomes weak.
If too high, excessive vibration may occur.
4. Alarm Messages
Common alarms include:
Over Range Alarm
Actual flow exceeds the meter’s maximum range.
Weak Signal Alarm
Usually caused by:
- low flow velocity
- sensor contamination
- poor wiring contact
Temperature / Pressure Limit Alarm
Process condition exceeds instrument rating.
For example:
- steam temperature too high
- pressure above design limit
How to Prevent Vortex Flow Meter Problems
Preventive measures are critical for stable long-term operation.
Ensure Proper Straight Pipe Length
This is the most important installation requirement.
Avoid Two-Phase Flow
For steam applications, install a steam trap.
For liquid service, install an air release valve.
Select the Correct Meter Size
Improper meter sizing is a major reason for low signal strength.
Need Help Troubleshooting Your Vortex Flow Meter?
If your project is experiencing:
- no signal
- unstable reading
- large deviation
- alarm issues
feel free to contact us.
We can help recommend the most suitable vortex flow meter based on:
- medium type
- pipe size
- temperature
- pressure
- flow range
This helps ensure accurate and stable performance in your application.