Troubleshooting Guides · Free Tool

Coriolis Flowmeter Fault Finder

Choose what the coriolis meter is doing and get the most likely causes, with the check to confirm each and the fix.

Flow at zeroNoisy flowDensity errorDrive gain

What do you see?

SymptomShows flow when the line is stopped

Most likely causeZero not set at process conditions

First checkCompare live zero with the commissioning value

Causes in order of likelihood

Cause	How to check	Fix
Zero not set at process conditions	Compare live zero with the commissioning value	Zero with meter full, flow stopped, at operating temperature
Pipe stress on the meter	Check supports and alignment; zero changes when bolts are loosened	Correct supports and alignment
Valve passing (real flow)	Close a second valve and watch	Repair the valve

Before You Start

Work under a permit, inform the control room and put the loop in manual or bypass the trip before touching a live instrument.
Read the diagnostics: drive gain, pickoff voltages, tube frequency and live zero.
Note the zero value recorded at commissioning.
Check the process: single phase, pressure well above vapour pressure.

Coriolis Flowmeter Fault Finder: All Symptoms

Shows flow when the line is stopped

Likely cause	How to check	Fix
Zero not set at process conditions	Compare live zero with the commissioning value	Zero with meter full, flow stopped, at operating temperature
Pipe stress on the meter	Check supports and alignment; zero changes when bolts are loosened	Correct supports and alignment
Valve passing (real flow)	Close a second valve and watch	Repair the valve

Flow and density noisy

Likely cause	How to check	Fix
Gas bubbles in liquid (two phase)	High or unstable drive gain	Raise back pressure; move meter lower; remove gas
Solids or cavitation	Check process and pressure at meter	Increase pressure; filter solids
External vibration near drive frequency	Compare with pumps running and stopped	Isolate vibration; change supports

Density reads wrong

Likely cause	How to check	Fix
Coating or erosion of tubes	Density check with lab sample or water	Clean tubes; contact maker if erosion
Gas entrainment	Drive gain high during error	Remove gas
Wrong density calibration factors	Compare with certificate	Restore factory factors

Drive gain high or sensor fault

Likely cause	How to check	Fix
Two phase flow or empty tubes	Check meter is full	Fill line; vent
Coil or cable fault	Measure coil resistance per manual	Repair cable or replace sensor
Tube damage	Persistent fault after fixes	Maker inspection

Reads correctly but totals disagree with tank

Likely cause	How to check	Fix
Totaliser counting at low flow noise	Check low flow cutoff	Set cutoff
Wrong units or density used for volume	Check configuration	Correct units
Tank level or strapping error	Check tank gauging	Correct the reference

Key insight: drive gain is the coriolis stethoscope: a rising drive gain almost always means gas, coating or empty tubes, long before readings fail.