Pressure and differential pressure relief controllers consist of a valve and a pressure actuator. Primarily used to limit a pressure (A) or differential pressure (PA) over a system/substation/pump.

Controllers are normally closed: AV(P)A due to a normally closed valve and AF(P)A due to a stretching spring.

Pressure and differential pressure relief controllers are primarily installed into a bypass. They can be used to enable heat power distribution to other network connections or idle flow in case the connection(s) close(s) completely.

Pressure and differential pressure relief controllers can protect variable flow pumps from overload in the event that flow falls below minimum pump capacity. They relieve pump/application and forward heat power to other connections.

A pressure relief controller can also be installed into the return to maintain a higher desired (static) pressure in the system.

Features and benefits

Relieve pump/application and forward heat power to other connections safely

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

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

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.

Tools and apps

Application guide

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 designed 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.

I can only achieve half of the pressure setting on AFPA, but I need to set much more!

Do not stop turning the setting nut when the shaft hides into it. There is still around 100mm stroke to do.

Case studies

  • 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.

  • 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.

  • 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. 

  • 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.

  • District heating network in HafenCity, Hamburg, Germany

    The district heating supply in the new Hamburg city quarter "HafenCity" is a costeffective and sustainable solution amongst other supplied by Danfoss.

  • 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.