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

Relief 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.

Selection tool

Application tool


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.

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 round 100 mm stroke to do.

Case studies