Flow Meter Troubleshooting

“Why has my Pulse Flow Meter Sensor failed?”

Titan Enterprises produce over 70,000 flowmeters each year that are used in a wide variety of industries, process and applications, so troubleshooting for customers is not uncommon, particularly for those who are unfamiliar with Titan’s flow metering products.

The majority of flow meters with a pulse output use a rotating element with internal magnets. These magnets trigger a solid-state sensor giving a pulse output proportional to the liquid flow rate. Although all Titan flow measuring devices are supported with written data and instruction sheets, errors in the flow meter installation process, such as mis-wiring, can damage the meter before the customer has even started!

Here we explain some of the reasons why these sensors might fail and what can be done to prevent damage that can lead to costly repairs and process downtime.

Troubleshooting Turbine or Oval Gear Flow Meter Failure

High quality Hall effect sensors are typically used within Titan’s pulse precision flow measurement devices. The sensors operate between 4.0Vdc and 30Vdc, however, there are a number of scenarios that will cause the Turbine and Oval Gear flow meters to fail, even though the installer believes the flow device has been installed correctly.

If a flow sensor fails, it may be for one of the following reasons:

Care must be taken when wiring the sensor power supply and pulse output of the flowmeter. The sensor is unable to cope with incorrect wiring – reverse polarity or short circuiting can cause the sensor to fail suddenly, completely and permanently.

Exceeding the maximum 30Vdc to the Hall Effect sensor will damage the unit. A good quality regulated DC power supply is recommended for powering a pulse flow meter.

Other connected equipment containing inductors (coils), or electromagnetic components (such as solenoid valves or pumps) can produce high voltage spikes when switching. These spikes can be a hundred to thousands of volts and if on the same circuit, will damage the flowmeter sensor beyond repair.

Electrical interference can also occur even without a direct connection if cabling is routed close to high-power equipment.
A failure mode that is commonly seen, is where a simple solenoid valve is operated on the same power supply as the flowmeter. When the solenoid de-energises in 1ms it produces a spike of 100s of Volts. Some of this voltage spike feeds through to the sensor, momentarily exceeding the 30Vdc maximum of the sensor causing it to fail.

What can be done to prevent catastrophic failures in flow measuring systems?

The majority of damage tends to be caused during the installation of the flowmeter. Minor errors can result in a non-operational meter before the customer has even started, leading to costly repairs or replacements, as well as process downtime, that can be avoided.

As well as following the specific flowmeter data and instruction sheets which come with your Titan flowmeter (and can be downloaded from our website), we have also published some installation tutorial videos to assist customers and prevent any mis-wiring that can damage the units.

Troubleshooting Flow Meter failure issues - wiring tutorial

Flow Meter Installation Checklist

The following installation checklist can help prevent common causes of pulse flow meter sensor failure:

Ensure polarity is correct and pull up resistors are fitted correctly before powering the flow measurement unit. Refer to the installation tutorial videos for support if necessary.

Always use a reputable regulated power supply to ensure the correct voltage is supplied to the meter.

Operating on a lower voltage gives headroom for any unavoidable voltage fluctuations and improves resilience to smaller voltage spikes.

The sensor power supply should not be shared with any equipment containing solenoids, motors or transformers that give any significant inductive load.

Install wiring away from high power cables and avoid switching equipment where possible to prevent interference.

If the above practices are not possible and external interference is a possibility, fit an inline DC EMI (Electromagnetic Interference) filter or a local voltage regulator.

This can help to control any unavoidable voltage spike to an acceptable level.

For any process or technical issues, please contact us on +44 (0)1935 812790 or email technical@flowmeters.co.uk

If returning a device to Titan Enterprises for repair, please print and complete either the UK or International Customer Returns Form and include with the package.

Downloads

Please click the image or title below to download useful flow meter articles. Alternatively, you can contact us if you have any questions.

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A Guide to Flowmeter Selection: 10 Common Mistakes PDF

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