OPTISONIC 3400 District Heating

Ultrasonic flowmeter for district heating applications

  • 3-path meter for thermal energy measurement and heated water
  • CT: OIML R75, MID MI-004 (Class 1, 2, 3)
  • Flange: DN25…2000 / 1…80", max. PN40 / ASME Cl 300
  • Max. +180°C / +356°F

OPTISONIC 3400 District Heating C – Compact version with flange

The OPTISONIC 3400 District Heating is a 3-path ultrasonic flowmeter for thermal energy measurement. It is dedicated to flow measurement in district heating networks, commercial and industrial heat metering applications as well as energy and utility applications in combined heat and electricity generation. The flowmeter is certified as meeting the requirements of OIML R75 (accuracy classes 1, 2 and 3) and MID MI-004. It can thus be used as part of heat metering systems in combination with a temperature sensor and a heat calculator.

The OPTISONIC 3400 District Heating is the only inline flowmeter for district heating that provides high accuracy measurement of heated water with three ultrasonic paths throughout the whole diameter range DN25…2000 / 1…80". With its direct path configuration, the flowmeter is not susceptible to (magnetite) scaling as compared to meters that use reflectors. It offers bi-directional flow measurement and a fully welded construction. The OPTISONIC 3400 District Heating also features enhanced diagnostic and status indications and measurement of the velocity of sound to gain additional information about medium and process.

Product highlights

  • Bi-directional flow measurement over a wide dynamic range
  • No influence of scaling due to direct path configuration
  • High accuracy for custody transfer and energy measurement
  • Certified to MID 2014/32/EU Annex VI
  • MI-004 approved starting from 0.1 m/s / 0.33 ft/s volume flow
  • Harmonized standard CEN EN14
  • Extensive sensor and process diagnostics (incl. NE 107)
  • Patented inert metal transducer technology
  • Full bore design: No moving parts, no wear, no pressure loss
  • Compact or field-mounted version (incl. cable length up to 30 m / 90 ft)

Typical applications


  • Custody transfer (fiscal metering) in district heating networks
  • Thermal energy management applications
  • Commercial and industrial heat metering applications
  • General energy and utility applications in combined heat and electricity generation

Related products

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  • Software and driver
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