API · ASME · DIN · EN standard industrial valves
Pilot Operated Pressure Reducing Valves
Pilot operated pressure reducing valves let downstream pressure act on a large diaphragm through a small pilot valve, so a compact body modulates high flows with accuracy a direct spring cannot hold — the choice for water networks where demand varies widely. The range covers a cast iron body and valve flap with cast iron press plate, NBR diaphragm, seal and O-rings, 20Cr13 screw and carbon-steel spring washer with Q235 bolting, designed according to EN-1074/4. Selection turns on the downstream setpoint and accuracy band, flow turndown across the network profile, and elastomer compatibility with the water quality.
Part of the Pressure Reducing Valves family
Last updated: 2026-11
Family specifications
| size range | 1-36 in (25-900 mm) flanged |
|---|---|
| size range | DN32-DN1400 |
| size range | DN65-DN600, flanged, ductile iron, PN10/PN16 (reduced bore) |
| size range | 2-8 in (50-200 mm) |
| pressure class | Ductile iron: 250 psi (150 Class flanged), 400 psi (300 Class flanged / grooved / threaded) |
| pressure class | PN10, PN16, PN25, PN40 |
| body materials | Cast Iron |
| design standards | EN-1074/4 |
| valve flap materials | Cast Iron |
| press plate materials | Cast iron |
| diaphragm materials | NBR |
| seal materials | NBR |
| o ring materials | NBR |
| screw materials | 20Cr13 |
| spring washer materials | Carbon Steel |
| bolt materials | Q235 |
| washer materials | Q235 |
| nut materials | Q235 |
| prA function | Automatically reduces higher inlet pressure to steady lower downstream pressure regardless of flow rate or inlet pressure changes |
| prA pilot control | Pilot-operated regulator holds downstream pressure to pre-determined limit; closes drip-tight when downstream pressure exceeds pilot setting |
| prA size range threaded grooved | 1-16 in (25-400 mm) threaded / grooved |
| prA body materials | Ductile Iron, Cast Steel, Bronze |
| prA trim materials | Bronze standard, stainless steel optional |
| prA seal materials | Disc: Buna-N rubber, Diaphragm: nylon-reinforced Buna-N rubber, Stem, nut and spring: stainless steel |
| prA anticavitation trim | Anti-cavitation trim option for high pressure drop, reducing noise and cavitation damage |
| prA low flow bypass | Integral low-flow bypass pressure regulator variants available for space savings |
| prA closing speed control | Optional closing speed control kept at least three turns off its seat |
| prA pilot train | Main valve + restriction fitting + pressure reducing pilot control |
| prB function | Reduces higher variable inlet pressure to constant lower outlet pressure, independent of flow and inlet changes |
| prC media temperature | Water and neutral liquids to max 70°C, reduced bore |
| prC function | Diaphragm-operated pilot control valves automatically reduce higher inlet pressure to lower outlet pressure, held constant regardless of flow or inlet changes |
| prC body materials | Ductile iron body and bonnet with 300 micron fusion bonded epoxy coating to DIN 3476 (WRAS-DVGW/W270/UBA) |
| prC internals | Non-coated internals stainless steel AISI 316 |
| prC seat design | Lifted seat to avoid cavitation damage |
| prC diaphragm design | Non-symmetric axial diaphragm position reduces stretch/stress near closed position |
| prC rubber approvals | Rubber components approved to EN 681-1, KTW, W270, ACS, WRAS |
| prC pilot system | Modular compact pilot system with distribution block, high-capacity back-flushable 100 mesh filter and balanced pilot valve |
| prD flange class | Class 150, Class 300 flanges |
| prD function | Automatically reduces higher inlet pressure to steady lower discharge pressure regardless of flow or inlet fluctuations |
| prD actuation | Diaphragm-actuated hydraulically operated design, stainless steel fasteners |
| o ring | NBR |
| hex bolts | Q235 |
| flat washers | Q235 |
| hex nuts | Q235 |
| flange standard | EN 1092/2 |
Ordering & documentation
Documents
Ask for the documentation set with the inquiry — typical items (material certificates, test reports to the listed inspection standard, dimensional drawings) are confirmed and supplied with the quotation.
Quotation
Send the medium, temperature, pressure, size and connection for a quotation-ready inquiry. Lead time, MOQ and price are confirmed at quotation, together with the documents to be supplied with the order.
Sample & supply
Supply terms, order quantities and lead time are agreed per order — state the destination country and required schedule with the inquiry.
Storage & shipping
Store valves with seats and seals protected from UV, ozone and deformation, and keep end-face protectors on until installation; storage limits and shipping arrangements for the selected materials are confirmed at quotation.
Frequently asked questions
What standards govern the design and testing of pilot operated pressure reducing valves?
The published specification for this family lists EN-1074/4 as the design standards.
What materials are pilot operated pressure reducing valves available in?
The published specification lists body materials: Cast Iron. Material availability for a specific size and rating is confirmed at quotation.
What should a quotation inquiry for pilot operated pressure reducing valves include?
The governing standard and class, nominal size, body and seat materials, the service medium with temperature, and the destination — anything missing is confirmed during quotation.
More in this family
Family
Pressure Reducing Valves
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Direct Acting Pressure Reducing Valves
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Steam Pressure Reducing Valves
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Water Pressure Reducing Valves
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Pressure Relief / Sustaining Valves
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