Pressure reducing valve · Direct-acting
PRV30 pressure reducing valve
316L stainless
Self-regulating, piston-balanced reducing valve made entirely of AISI 316L stainless steel. It keeps the outlet pressure constant even when the inlet pressure fluctuates, in water, compressed air, and inert gases, up to 25 bar.
- SizesDN15 to DN25
- Pressure ratingPN25
- Inlet pressureup to 25 barg
- Outlet pressure0.5 to 12 barg
- Temperature−30 to 150 °C depending on gaskets
- Kv2 to 3.5 m³/h
Configure your valve
Questions about sizing? Call 933 720 888 or email valfonta@valfonta.com.
- In-house design and manufacturing in Badalona
- ATEX II 2 GD marking for zones 1 and 21
- No routine maintenance
- Genuine spare parts available
What the PRV30 is used for
The PRV30 is a direct-acting pressure reducing valve: it needs no auxiliary power or pilot line. The fluid itself and an adjusting spring balance the piston, so the downstream pressure stays at the set value even when the inlet pressure rises or falls.
Because the body, the cap, and all internals are made of AISI 316L stainless steel, it is a common choice in installations where corrosion or fluid cleanliness is critical. Its internal design allows efficient fluid flow, and it requires no routine maintenance.
- Chemical laboratoriesSupplying equipment and test benches with stable pressure.
- Sanitary plantsWater and fluid networks where stainless steel is required.
- Compressed airReducing the network pressure to the working pressure of each machine.
- Sprinkler systemsStabilizing the pressure in fire protection water installations.
- Water networksProtecting equipment and points of use against pressure peaks.
- Inert gasesGroup 2 gases, such as nitrogen, in small-diameter lines.
- Desalination plants316L stainless steel against brine and salt spray in coastal plants: stainless steel PRVs for desalination plants.
PRV30 technical specifications
| Type | Self-regulating, direct-acting, piston-balanced pressure reducing valve |
|---|---|
| Sizes | DN15 (½″), DN20 (¾″), and DN25 (1″) |
| Connections | BSP or NPT thread · EN PN16/25 flanges · ANSI CL150 flanges |
| Pressure rating | PN25 |
| Maximum inlet pressure | 25 barg |
| Outlet pressure ranges | 0.5 – 3 barg · 1 – 8 barg · 4 – 12 barg (depending on spring) |
| Kv coefficient | 2 m³/h (DN15) · 2.5 m³/h (DN20) · 3.5 m³/h (DN25). Reduced Kv on request |
| Temperature depending on gaskets | NBR: −30 to +80 °C · EPDM: −10 to +125 °C · Viton: −10 to +150 °C |
| Fluids | Group 2 liquids and gases: water, oil, compressed air, inert gases |
| Materials | Body, cap, and internals in AISI 316L stainless steel (1.4404). NBR gaskets as standard |
| Mounting position | Recommended in a horizontal pipe; the design allows other positions |
| Pressure Equipment Directive | PED 2014/68/EU, Article 4.3: CE marking not required |
| ATEX | II 2 GD c IIC Tx / c IIIC TxºC · certificate LOM 14.034 U |
| On request | Body and cap in super duplex · weld ends (socket weld or butt weld) · clamp connection · degreased for oxygen service · EPDM, PEEK, Viton, or Aflas gaskets |
Dimensions and weight
| ½″ threaded | ¾″ threaded | 1″ threaded | DN15 EN | DN20 EN | DN25 EN | DN15 ANSI | DN20 ANSI | DN25 ANSI | |
|---|---|---|---|---|---|---|---|---|---|
| Kv (m³/h) | 2 | 2,5 | 3,5 | 2 | 2,5 | 3,5 | 2 | 2,5 | 3,5 |
| Length A / AA | 108 | 108 | 108 | 130 | 150 | 160 | 184 | 184 | 184 |
| Height H1 | 135 | 135 | 135 | 135 | 135 | 135 | 135 | 135 | 135 |
| Height H2 | 185 | 185 | 185 | 185 | 185 | 185 | 185 | 185 | 185 |
| Flange Ø D1 | – | – | – | 95 | 105 | 115 | 89 | 98 | 108 |
| Weight (kg) | 3,5 | 3,5 | 3,5 | 5 | 5 | 5 | 5 | 5 | 5 |
Dimensions in millimeters. The dimensioned drawings and the remaining flange dimensions are in the PDF datasheet.
Exploded view and materials (22 parts)
| No. | Part | Material |
|---|---|---|
| 1 | Body | Stainless steel 1.4404 (316L) |
| 2 | Sealing screw | 1.4404 (316L) |
| 3 | Seat | NBR |
| 4 | Gasket | PTFE |
| 5 | Seat | 1.4404 (316L) |
| 6 | Gasket | PTFE |
| 7 | Cap | 1.4404 (316L) |
| 8 | Spring washer | Steel ST-52 |
| 9 | Adjusting screw | Stainless steel A2-70 |
| 10 | Adjusting spring | Steel 52SiCrNi5 with epoxy paint |
| 11 | Piston | 1.4404 (316L) |
| 12 | O-ring | NBR |
| 13 | Gasket | NBR |
| 14 | Screws (x4) | Stainless steel A2-70 |
| 15 | O-ring | NBR |
| 16 | O-ring | NBR |
| 17 | Stem | 1.4404 (316L) |
| 18 | Seat guide | 1.4404 (316L) |
| 19 | Closing spring | Stainless steel 302 |
| 20 | Bushing guide | 1.4404 (316L) |
| 21 | Bottom cover | Stainless steel AISI 316 |
| 22 | Gasket | NBR |
Recommended spare parts
| Reference | Description | Parts |
|---|---|---|
| PRV30.SP1 | Gasket and seat kit | 3, 6, 12, 13, 15, 16 and 22 |
| PRV30.SP2 | Gasket kit | 6 and 22 |
| PRV30.SP3 | Springs | 10 and 19 |
How the PRV30 works
The PRV30 works by balancing the forces between the adjusting spring and the outlet pressure acting on the piston. It needs no air, electricity, or external pressure sensing points.
- Closing by inlet pressure. The fluid enters the valve and, due to the difference in areas, the inlet pressure tends to close it.
- Opening with the spring. When the adjusting spring is compressed with the top screw, the closing assembly (piston, stem, and seat disc) lifts off the seat and lets the fluid through.
- Regulation. The outlet pressure pushes the piston against the spring. When it reaches the set value, the valve balances and lets through only the flow being consumed.
- Shutoff at zero demand. If the downstream valves are closed, the PRV30 closes, absorbs the fluctuations, and holds the set outlet pressure.
Video of the PRV30 model.
PRV30 installation
A reducing valve performs well if the line is properly prepared. This is the layout recommended by the manufacturer, with a bypass so that maintenance can be carried out without interrupting service. For more detail, see our guides on how to install a pressure reducing valve and where to install it.
- Shutoff valves (1, 1a) and bypass valve (1b)
- Strainer
- Inlet pressure gauge
- PRV30 reducing valve
- Safety valve, 0.5–1 m from the reducing valve
- Outlet pressure gauge
Installation and start-up
- Clean the pipe before installing the valve: any debris or particle can damage the seat.
- Install a strainer upstream to protect the piston and the seat.
- Follow the arrow on the body and, whenever possible, install the valve in a horizontal pipe.
- Support the pipe, not the valve: supports should be as close as possible to the reducing valve, but never attached to it.
- Leave 0.5 to 1 m of pipe up to the outlet safety valve for better compensation.
- Start up slowly: open the shutoff valves gradually to avoid water hammer.
- Adjust the outlet pressure with an 8 mm Allen key on the adjusting screw. Compressing the spring raises the outlet pressure; releasing it lowers it. Check the value on the outlet pressure gauge.
The valve must be installed by qualified personnel and must never exceed the operating pressure and temperature for which it was sized. In ATEX zones, the valve must be equipotentially bonded to the installation. If the outlet pressure is unstable, review the most common problems with reducing valves.
PRV30 technical documentation
Do you need an order certificate or the ATEX documentation? See our quality certificates or request it from our technical team.
PRV30 vs. other Valfonta reducing valves
The reducing valve range covers DN8 to DN150. This table helps you check whether the PRV30 is the right model or whether another one suits you better.
Temperature in parentheses: with EPDM or Viton gaskets. Data from the Valfonta general pressure reducing valve catalog (2025). If you are unsure whether to choose a piston or a diaphragm valve, read our comparison of piston and diaphragm reducing valves.
Frequently asked questions about the PRV30
Can the PRV30 be used with steam?
What outlet pressure can be set?
The outlet pressure depends on the adjusting spring. There are three ranges: from 0.5 to 3 barg, from 1 to 8 barg, and from 4 to 12 barg. The inlet pressure can be up to 25 barg.
How do you adjust the outlet pressure of the PRV30?
With an 8 mm Allen key on the adjusting screw. Compressing the spring raises the outlet pressure, and releasing it lowers it. Make the adjustment with the installation in service and check the value on the outlet pressure gauge. We explain it step by step in how to adjust a pressure reducing valve.
In what position should it be installed?
Installation in a horizontal pipe is recommended, following the flow direction arrow on the body. Its internal design allows other positions, although the manual indicates that some permitted orientations are not recommended.
What maintenance does it need?
It needs no routine maintenance. The gaskets and wear parts should be checked at intervals that depend on the operating conditions. Maintenance can be carried out with the valve installed, always depressurized and isolated. There are three spare parts kits: gaskets and seat (PRV30.SP1), gaskets (PRV30.SP2), and springs (PRV30.SP3).
Does the PRV30 carry CE marking?
It does not need it. Given its size (DN15 to DN25), pressure rating (PN25), and fluid type (Group 2), it falls under Article 4.3 of the Pressure Equipment Directive 2014/68/EU, which does not require CE marking.
Can it be installed in an ATEX zone?
Yes. The PRV30 carries ATEX II 2 GD marking (certificate LOM 14.034 U) and can be used in zones 1 and 2 (flammable gases, vapors, and liquids) and 21 and 22 (combustible dust), within the temperature class corresponding to the fluid temperature.
What is its Kv coefficient?
The standard Kv is 2 m³/h for DN15, 2.5 m³/h for DN20, and 3.5 m³/h for DN25. A reduced Kv for small flow rates is available on request.
Other pressure reducing valve models
PRV44 reducing valveDN15–25 and PN25 like the PRV30, but suitable for steam up to 210 °C.
PRV20 reducing valve316L stainless, DN8–20 and up to 40 bar inlet.
PRV45 reducing valveVery low outlet pressures, from 0.01 barg; suitable for steam.
VD reducing valveFrom DN15 to DN100, up to 40 bar, and steam up to 200 °C.
M1 reducing valveUp to DN150 and 220 °C, for steam.
M2 diaphragm reducing valveDN15–100, outlet pressures from 0.02 barg, and steam up to 180 °C.
M2 bellows reducing valveVersion with a sealing bellows.
Request a quote for the PRV30
Give us your installation details and we will recommend the right size, spring range, and gaskets.
- Fluid and operating temperature
- Inlet pressure and desired outlet pressure
- Maximum and minimum flow rate
- Connection type (threaded or flanged)
You can also call 933 720 888.
