Frequent questions (FAQ) about water meters
Measurement of water can be done in many ways and it comes to choosing the right type, size, and accessories to achieve the best results. It is most important that you are clear about what you really want. We get a lot of questions about the meters and would like to respond to some of those questions here:
Metering technology issues
What is the difference between static and mechanical water meters?
Static meters have no moving parts while mechanical meters measures flow by making components move when the water passes. A common misunderstanding is that static meters have a longer life than mechanical. It is wrong and often contrary. We have validated 30 years old mechanical meters that are still accuracy.
What is the difference between a vane wheel meter and a multijet meter?
Both types have a vane wheel that rotates when water passes. The difference is that the in the multijet meter water flows into the wheel from all sides. The result is less wear for longer life and higher long-term accuracy. Multijet meters should always be the first choice where economics and technology allow.
Why don't you sell ring piston meters?
Aquametro is the world's largest manufacturer of ring piston meters for oil. Yet they choose not to manufacture ring piston meters for water. The technology exists and the meters work, but increase the demand on water purity. Particles in the water and shock damage meters quickly and severely. To remove the responsibility of our customers, with downtime and loss of accuracy, we have chosen not to work with ring piston meters for water.
NOTE! Ring piston meters can have a metrological class C as opposed to multijet meters with class B. It makes very little difference and it needs an industrial application for Class C to be required. Class B-meters have a so much better accuracy over time that in practice it will be more accurate.
What does the different accuracy classes really mean?
The EU has standardized accuracy classes so meters can be compared. We try here to simplify the otherwise rather long, complicated explanation:
- Cold water has a standard requirement that says ± 2% error display. They must follow the standard OIML R
- Hot water meter is divided into Class 2 (± 2% error display) and Class 3 (± 3% error display)
- All meters have ± 5% accuracy below the transitional flow rate
- The meters are also divided in metrological classes A...E depending on how accurate they are at extremely low flows where class E is the most accurate, but the Class B usually keep accuracy the longest
- Most common is to select Class 2 meter and metrological class B.
- When connecting the meter to a heat calculator it is sometimes requires that the meter is MID approved. See the meter's data sheet.
Mounting
Can all meters be installed both horizontally and vertically?
Some meters can be installed both horizontally and vertically, but some have to be specially adapted for vertical flow. Normally, one must also know whether the vertical flow is upward or downward. Some meters may be less accurate in vertical flow. Horizontal flow is always preferred.
How are the water meters best installed?
See the operating instructions for best results. Remember that flows over the specified nominal flow rate of more than a few minutes at a time can damage the meters.
Check the required straight pipeline before and after the meter.
Always use a filter before the meter.
Always install the counter pointing up (unless otherwise specified in the operating instructions).
Avoid installing meters where they can be affected by moisture, sunlight or extreme temperatures.
Ask us for advice.
Maintenance
How long do we carry spare parts?
It depends of course on the manufacturer, but we usually supply the market with spare parts for at least 20 years as we sell meters with long life.
Communication
How do I connect the meter to external equipment such as remote meter reading, calculator or controller?
There are many different solutions to this and we can supply meters with pulse, analog signal, M-Bus, Modbus, LON, N2Open, BACnet etc.
Most common is pulse signal or M-bus and some meters can be retrofited. If the meter is to be connected to a calculator, use a meter with built-in pulse signal to ensure that it can not be manipulated.
