● The flow rate in the pipe is too high, so components sitting in front of the flowmeter can cause
cavitation.
● If there is a filter installed before the flowmeter, it may be close to blocking, which also can
cause cavitation.
● Liquid flashes to vapor bubbles while passing through partially open valves or orifices.
● The piping on the pump suction side, pump gaskets or the pump itself is not tight. Air gets
sucked into the system due to a low pressure on the pump suction side.
● The piping on the pump suction side, pump gaskets or the pump itself is not tight. Air gets
sucked into the system due to a low pressure on the pump suction side.
Solid particles in the liquid
If the solid particles in a liquid have a density higher than that of the liquid, they can precipitate
inside the sensor and cause instability which leads to a measurement error.
If solid particles are present in the liquid, they must be homogeneously distributed and have
similar density as the liquid. Otherwise they can cause relatively large measurement errors.
It is important that the sensor is installed so that solid particles can easily run out of the sensor.
1. Ensure that the sensor is installed vertically with an upwards flow.
2. Check if solid particles are present in the liquid:
Take a sample of the liquid, fill a glass and see if the solids precipitate.
Diagnostics and troubleshooting
10.3 Operation troubleshooting
SITRANS FC330
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Operating Instructions, 01/2019, A5E44030648-AB