UF4 / UFR4 Series - Pressure Relief Valves

Product Type(s) : Relief Valves
Description :

UF3 and UFR3 Valves are used to protect pumps and other related process equipment in the event of a pressure spike downstream of the pump.  These valves can be set to relieve pressure in the range of 0-10 bar.  

New: UF4 and UFR4 Series is being introduced to deliver this same functionality with the advantages of added controls to monitor pressure release events, and to actuate the valve during any required CIP cleaning.  

Note: UF3 and UFR3 valves will still be available through the end of the 2023 and existing installations can be updated to include these added features through inserts. Standard options are available up to 10 bars, for higher pressures or for ATEX UF4/UFR4 options please consult SPX FLOW.​




Optimum cleanability

  • No dead spaces in the valve body
  • No stroke limitation by seat lift actuator; the full opening cross section is available during cleaning
  • 3-A approved designs available / Designed to EHEDG guidelines
  • All product-contact parts are made of AISI 316L / DIN EN 1.4404 stainless steel.

Minimize Downtime

  • Enhanced control for improved response to pressure relief events (through proximity switches or through control unit feedback)
  • All valves come with a seal lifting function to open the valve during cleaning operation which helps minimize downtime
  • Clamps allow for a service friendly design 

Optimize your process 

  • Protect your pump with an external over-pressure relief valve. If pump discharge pressure exceeds the set cracking-pressure, the valve will open to a relief path
  • The modulating cone of the UFR4 valve provides for slower, smoother closing of the valve when low flow is expected and prevent pressure hammers
  • Leverage the breadth of options to standardize your operations: can be supplied in nominal diameters from DN25 to DN100 and ISO 1" to 4"


  • Ball shaped valve body with smooth passages, i.e., no sump and dome, making CIP-cleaning more efficient and more reliable. 
  • Seat lift actuator as a standard offering with feedback switches on top of the actuator. 
  • UF4/UFR4 replacement insert fits into existing UF3/UFR3 housing making an easy upgrades to next generation with improved features. 
  • Wide range of pressure settings can be achieved using four different actuators. 
  • UF4 maintenance free actuator minimizes maintenance costs and downtime 
  • The metal stop ensures defined compression of the seat seal, reducing material stress.  
  • The UF4/UFR4 valves can be delivered with a comprehensive range of CU4, CU4plus control units.  
Theory of Operation

UF pressure relief valves use a standard shut-off type disc for closing against product and are suitable for general applications.

To provide smoother transitions from open to closed and to maintain constant pressure, UFR valves feature a profiled cone design.  This design minimizes the unwanted effects related to water hammer to further protect the pump.​ ​

Both UF and UFR relief valves open when the pressure in the outlet increase above the set point of the valve in over pressure conditions. This prevents pumps from producing excess pressure which can cause a pipeline to burst. Over pressure conditions can also damage to coupling, rotors, rotor casing, and pumps shafts.​



  • Product wetted parts: 316L, 1.4404 (DIN EN 10088) 
  • Non-Product wetted parts: 304, 1.4301 (DIN EN 10088) 
  • Seal: EPDM, HNBR, FPM (FDA Compliant) 
  • Internal Surface Finish: ≤32 Ra (≤0.8µ)


  •  1” – 4” O.D. Tube 
  •  DN25 – DN 100

Pressure Ratings: 

  • Operating Pressure: 0 – 10 BAR 

Temperature Ratings:

  • EPDM, HNBR - 275ºF (135ºC), short time - 284ºF (140ºC)  
  • FPM (not to be used for hot water) - 212ºF (100ºC) 


Wide range of housing/body configurations

  • Comprehensive range of valve housings are available to cover any requests. 

Control Unit:

  • The UF4/UFR4 valves can be delivered with a comprehensive range of CU4, CU4plus control units. The CU4, CU4plus are electrically provided to connect direct (DC) to a PLC system (CU4, CU4plus Direct connect) and to fieldbus protocols such as AS-i.  Additionally, CU4plus also supports fieldbus protocol such as IO-link. 

Proximity switch:

  • Proximity switches detects valve full open or close condition during any required CIP cleaning.

Regulating (controlled) cone variant:

  • Optimized control cone design provides slower, smoother valve closure to avoid water hammers. 

Retrofit kits:

  • Retrofit kits or Replacement inserts fits into existing UF3/UFR3 housings making an easy upgrade to next generation with improved features. 
  • To simplify our designs and offer the use of the CU4 control unit on UF3 valves, UF3 to UF4 retrofit kits are being made available.
  • These retrofit actuator kits, include the UF4 actuator, yoke and stem, are designed to fit directly into legacy UF3 body.
  • UF3 aftermarket parts (including actuators and seal kits) will remain available to service the legacy installed base.  These parts are all available in the manual.