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Differential pressure controllers & flow controllers / limiters

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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.

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

Heat Selector

Danfoss Heat Selector is the best-in-class online selection tool that optimizes planning process for heating application experts.

Open Heat Selector

FAQ

Can I limit a max flow with a differential pressure regulator?

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 design an installation and need lengths of valves from a project specification.

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.

We have installed a DN125 differential pressure controller, but found out that we need a bigger setting range. Do we need to order a new pressure actuator?

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.

I am installing a AFPQ controller. I do not know how to connect impulse tubes?

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 stories

City of Banja Luka
Danfoss partners with the city of Banja Luka to decarbonize district energy

The Challenge: Renovate 34 of the city’s largest heating substations
The Solution: Danfoss Leanheat® Monitor enables full substation digitalization
The Results: reduced heat consumption by 10%

Eurasburg
Successful transition from oil boilers to a local heating network in Eurasburg

In the Wittelsbacher Land near Augsburg the local network in Eurasburg supplies heat to 80 buildings using a wood chip heating system. Danfoss’ substations ensure efficient heating in all building types, and its modern SCADA solution enables remote system monitoring and management. 

Saleska valley, Slovenia
Improved hydronic balancing of the district heating network in Slovenia

The Saleska Valley district heating network is the second largest network in Slovenia, dating back to 1959. Since then, the demands have changed significantly and have challenged the hydronic balancing of the system which was optimized with new intelligent controllers Virtus.

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SOUTH KOREA: The South Korean National Institute of Fishery Science is enjoying great fuel savings and 20-30% less emissions from its newest research vessel. A special shaft generator solution enabled the vessel to comply with the IMO environmental regulations effective in 2020.

In Helsinki a total of 667 addresses in a mix of large and small buildings and apartments have had the Leanheat software installed.
Leanheat makes buildings smart

In Europe, 30 percent of all energy consumption goes to heat or cool buildings. Danfoss has the solution to lower energy usage and improve indoor climate by adding a digital element: Leanheat software.

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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