Differential pressure controllers & flow controllers / limiters

  • Overview
  • Tools and apps
  • FAQ
  • Case studies
  • Videos

A combined differential pressure controller and flow controller (PQ) consists of two independent differential pressure controllers and a flow restrictor (manual balancing valve) integrated in one valve body.

This device has two functions:

1) A differential pressure controller maintains fixed differential pressure over the flow restrictor (flow control). This ensures automatic flow limitation, independent of pressure variations in the system.

2) A differential pressure controller maintains constant differential pressure over motorized control valves or over the entire loop.

This is the best solution for the district heating utility as it enables both variables (maximum flow and differential pressure) to be set independently of the consumer’s heating control system. Especially when the subscriber station is owned by the consumer, the utility has no influence over flow limitation at the consumer’s end of the system.

This enables the district heating utility to control the flow available for each consumer as well as the differential pressure control at the substation. This allows efficient network balancing.

Another solution is the PB controller, which consists of one pressure controller and a flow restrictor (manual balancing valve). The PB is used in systems where independent flow and differential pressure are not required.

Differential pressure and flow controllers in district heating or cooling systems (variable flow)

Balance your network, save energy and improve end user comfort by hydronic balancing and control of district energy networks.

Features and benefits

Eliminates pressure variations and provide optimum operating conditions with improved temperature control quality

Made for demanding systems, resistant to corrosion, cavitation and dirt

Connected system is protected against pressure surges, fluctuations, cavitation and noise

Tools and apps

Application guide


Yes you can. Open the control valve fully and set the max flow by adjusting the differential pressure. You can also calculate the appropriate differential pressure, but you need to know the exact capacity of the control valve.

We produce valves with a standard length. You can also find the measures in our datasheet or download 2D and 3D CAD drawing models from our product presentations. Please go to our product catalog where you will find links to documentation and drawings - follow the below link.

No, you do not need to change the pressure actuator. It will be sufficient to replace the setting spring only. Please contact your local sales or technical support for further instructions.

Please use the instructions shipped with the product or open the online version of it by clicking the link: https://assets.danfoss.com/documents/DOC000086446982/DOC000086446982.pdf

Case studies

  • if (isSmallPicture) { A cost-effective solution: district cooling in central Copenhagen; } else if (isBigColumns) { A cost-effective solution: district cooling in central Copenhagen } else { A cost-effective solution: district cooling in central Copenhagen }
    A cost-effective solution: district cooling in central Copenhagen

    Energy efficiency was a major consideration in the design of Copenhagen’s district cooling project, where VLT® drives contribute to reducing CO2 emissions by more than 3000 t annually.

  • if (isSmallPicture) { Solar heating plant reduces CO2 emissions by 15,700 tonnes annually; } else if (isBigColumns) { Solar heating plant reduces CO2 emissions by 15,700 tonnes annually } else { Solar heating plant reduces CO2 emissions by 15,700 tonnes annually }
    Solar heating plant reduces CO2 emissions by 15,700 tonnes annually

    The world’s largest solar heating plant in Silkeborg, Denmark harnesses energy to heat the homes and workplaces of 40,000 citizens. It supplies 18-20% of the annual heat consumption in the city of Silkeborg, Denmark, which has an ambitious target of CO2 neutrality in heat production by the year 2030.

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    District energy as the heating and cooling solution in Teknopark Istanbul, Turkey

    Building: Office
    Application: Production of heating, cooling and domestic hot water
    Challenge: Design and construct customized district energy solutions for all buildings on the park
    Solution: Danfoss  designed and constructed 3 pre-assembled DSE substations containing control valves for the heating, cooling and domestic hot water, heat meters, self-acting controllers and electronic controllers connected to a central Building Management System. 

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    First ever district heating system with substations in Turkey

    600 residents in the town of Soma in Western Turkey now enjoy the comforts of a reliable and cheap heat supply from the town’s brand new district heating system. 

    In the coming years, more than 8,000 households will be joining the system that exploits the excess heat from the municipal power plant – a great improvement from the charcoal boilers of the past, and much less expensive.

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    Buildings connected to district heating, Tuzla, Bosnia

    So far, 70% of all buildings in the city have been connected to the district heating system and the network is gradually being optimized. In the near future, two hospitals, one of them a big regional center, will be connected as well.