Pressure Reducing Valves Β· Pressure Relief / Sustaining Valves
500X Pressure Relief Valves
The 500X pressure relief valve is the hydraulically operated, diaphragm-actuated execution of the water-control relief family: a pilot senses upstream pressure and modulates the main diaphragm valve to spill excess pressure at the set point, holding the upstream (sustaining) level while excess flow is discharged, which protects pumps and upstream mains from over-pressure in the same body that can serve pure relief duty. The benchmark execution covers DN20 to DN800 with flanged dimensions tabulated at PN1.0, PN1.6 and PN2.5, and is installed on horizontal piping per the source page.
Part of the Pressure Relief / Sustaining Valves family
Last updated: 2026-11
Specifications
| size range | DN20 to DN800 |
|---|---|
| installation orientation | Install on horizontal piping |
| flange pressure classes | PN1.0, PN1.6, PN2.5 |
| dimensions dn20 | DN20: L=180, A=330, A1=130, H=550, H1=460, F=116, D=105/105/105 (PN1.0/1.6/2.5), D1=75/75/75 (PN1.0/1.6/2.5), D2=58/58/56 (PN1.0/1.6/2.5), bolts=4-13.5/4-13.5/4-14 (PN1.0/1.6/2.5) |
| dimensions dn50 | DN50: L=240, A=345, A1=135, H=610, H1=516, F=170, D=165/165/165 (PN1.0/1.6/2.5), D1=125/125/125 (PN1.0/1.6/2.5), D2=102/102/99 (PN1.0/1.6/2.5), bolts=4-17.5/4-17.5/4-18 (PN1.0/1.6/2.5) |
| dimensions dn100 | DN100: L=360, A=400, A1=156, H=750, H1=596, F=275, D=220/220/235 (PN1.0/1.6/2.5), D1=180/180/190 (PN1.0/1.6/2.5), D2=158/158/156 (PN1.0/1.6/2.5), bolts=8-17.5/8-17.5/8-22 (PN1.0/1.6/2.5) |
| dimensions dn150 | DN150: L=455, A=435, A1=186, H=864, H1=710, F=355, D=285/285/300 (PN1.0/1.6/2.5), D1=240/240/250 (PN1.0/1.6/2.5), D2=212/212/211 (PN1.0/1.6/2.5), bolts=8-22/8-22/8-26 (PN1.0/1.6/2.5) |
| dimensions dn25 | DN25: L=180, A=330, A1=130, H=550, H1=460, F=116, D=115/115/115 (PN1.0/1.6/2.5), D1=85/85/85 (PN1.0/1.6/2.5), D2=68/68/65 (PN1.0/1.6/2.5), bolts=4-13.5/4-13.5/4-14 (PN1.0/1.6/2.5) |
| dimensions dn32 | DN32: L=180, A=330, A1=130, H=550, H1=460, F=116, D=140/140/140 (PN1.0/1.6/2.5), D1=100/100/100 (PN1.0/1.6/2.5), D2=78/78/76 (PN1.0/1.6/2.5), bolts=4-17.5/4-17.5/4-18 (PN1.0/1.6/2.5) |
| dimensions dn40 | DN40: L=240, A=345, A1=135, H=610, H1=516, F=170, D=150/150/150 (PN1.0/1.6/2.5), D1=110/110/110 (PN1.0/1.6/2.5), D2=88/88/84 (PN1.0/1.6/2.5), bolts=4-17.5/4-17.5/4-18 (PN1.0/1.6/2.5) |
| dimensions dn65 | DN65: L=250, A=355, A1=140, H=625, H1=520, F=180, D=185/185/185 (PN1.0/1.6/2.5), D1=145/145/145 (PN1.0/1.6/2.5), D2=122/122/118 (PN1.0/1.6/2.5), bolts=4-17.5/4-17.5/8-18 (PN1.0/1.6/2.5) |
| dimensions dn80 | DN80: L=285, A=360, A1=146, H=645, H1=538, F=210, D=200/200/200 (PN1.0/1.6/2.5), D1=160/160/160 (PN1.0/1.6/2.5), D2=133/133/132 (PN1.0/1.6/2.5), bolts=8-17.5/8-17.5/8-18 (PN1.0/1.6/2.5) |
| dimensions dn125 | DN125: L=400, A=420, A1=170, H=808, H1=655, F=310, D=250/250/270 (PN1.0/1.6/2.5), D1=210/210/220 (PN1.0/1.6/2.5), D2=184/184/184 (PN1.0/1.6/2.5), bolts=8-17.5/8-17.5/8-26 (PN1.0/1.6/2.5) |
| dimensions dn200 | DN200: L=585, A=480, A1=206, H=1135, H1=805, F=460, D=340/340/360 (PN1.0/1.6/2.5), D1=295/295/310 (PN1.0/1.6/2.5), D2=268/268/274 (PN1.0/1.6/2.5), bolts=8-22/12-22/12-26 (PN1.0/1.6/2.5) |
| dimensions dn250 | DN250: L=650, A=530, A1=226, H=1185, H1=855, F=500, D=395/405/425 (PN1.0/1.6/2.5), D1=350/355/370 (PN1.0/1.6/2.5), D2=320/320/330 (PN1.0/1.6/2.5), bolts=12-22/12-26/12-30 (PN1.0/1.6/2.5) |
| dimensions dn300 | DN300: L=800, A=575, A1=246, H=1325, H1=955, F=580, D=445/460/485 (PN1.0/1.6/2.5), D1=400/410/430 (PN1.0/1.6/2.5), D2=370/370/389 (PN1.0/1.6/2.5), bolts=12-22/12-26/16-30 (PN1.0/1.6/2.5) |
| dimensions dn350 | DN350: L=860, A=620, A1=275, H=1385, H1=990, F=640, D=505/520/555 (PN1.0/1.6/2.5), D1=460/470/490 (PN1.0/1.6/2.5), D2=430/430/448 (PN1.0/1.6/2.5), bolts=16-22/16-26/16-33 (PN1.0/1.6/2.5) |
| dimensions dn400 | DN400: L=960, A=635, A1=286, H=1445, H1=1030, F=715, D=565/580/620 (PN1.0/1.6/2.5), D1=515/525/550 (PN1.0/1.6/2.5), D2=482/482/503 (PN1.0/1.6/2.5), bolts=16-26/16-30/16-36 (PN1.0/1.6/2.5) |
| dimensions dn450 | DN450: L=1075, A=665, A1=320, H=1325, H1=905, F=780, D=615/640/670 (PN1.0/1.6/2.5), D1=565/585/600 (PN1.0/1.6/2.5), D2=532/550/548 (PN1.0/1.6/2.5), bolts=20-26/20-30/20-36 (PN1.0/1.6/2.5) |
| dimensions dn500 | DN500: L=1075, A=695, A1=348, H=1430, H1=960, F=830, D=670/715/730 (PN1.0/1.6/2.5), D1=620/650/660 (PN1.0/1.6/2.5), D2=585/585/609 (PN1.0/1.6/2.5), bolts=20-26/20-33/20-36 (PN1.0/1.6/2.5) |
| dimensions dn600 | DN600: L=1230, A=720, A1=372, H=1565, H1=1020, F=920, D=780/840/845 (PN1.0/1.6/2.5), D1=725/770/770 (PN1.0/1.6/2.5), D2=685/685/720 (PN1.0/1.6/2.5), bolts=20-30/20-36/20-39 (PN1.0/1.6/2.5) |
| dimensions dn700 | DN700: L=1650, A=770, A1=422, H=1755, H1=1160, F=980, D=895/910/960 (PN1.0/1.6/2.5), D1=840/840/875 (PN1.0/1.6/2.5), D2=800/800/820 (PN1.0/1.6/2.5), bolts=24-30/24-36/24-42 (PN1.0/1.6/2.5) |
| dimensions dn800 | DN800: L=1750, A=805, A1=458, H=2230, H1=1515, F=1050, D=1015/1025/1085 (PN1.0/1.6/2.5), D1=950/950/990 (PN1.0/1.6/2.5), D2=905/905/928 (PN1.0/1.6/2.5), bolts=24-33/24-39/24-48 (PN1.0/1.6/2.5) |
Application & selection guidance
Choose this execution where a water system needs upstream pressure protection at waterworks ratings: downstream of pumps and supply headers that must not rise above a set pressure, on branch take-offs that need a sustaining function holding a minimum upstream level while the valve spills the surplus, and on fire-service or irrigation headers where a pilot-set relief point matters more than continuous throttling. Confirm the size within the tabulated DN range against the PN1.0/PN1.6/PN2.5 flange drilling, orient the valve on horizontal piping as the source specifies, and set the pilot to the required relief or sustaining pressure at commissioning.
Frequently asked questions
What does the 500X do differently from a spring relief valve?
A spring relief snaps open and re-closes, cycling with every pressure ripple. The 500X is a pilot-controlled, diaphragm-actuated valve: the pilot modulates the main valve so it relieves or sustains at the set point with controlled travel, which suits pump headers and supply mains where smooth upstream-pressure protection matters more than a crack-open action.
What sizes and ratings does this execution cover?
The source page tabulates main dimensions from DN20 to DN800, with flange dimensions D, D1, D2 and bolt circles given separately for PN1.0, PN1.6 and PN2.5. Face-to-face L, overall A/A1 and heights H/H1 are tabulated per size, and the valve is installed on horizontal piping.
What information is needed to quote a 500X pressure relief valve?
Nominal size within the tabulated range, the flange pressure class (PN1.0, PN1.6 or PN2.5) against the system, the required relief or sustaining set pressure for the pilot, and the installation orientation - the source specifies horizontal piping. The pilot setting fixes the protection point; the size and class fix the flange pattern.
Ordering & documentation
Documents
Ask for the documentation set you need with the inquiry β typical items for this execution (material certificates, test reports to the listed inspection standard, dimensional drawings) are confirmed and supplied with the quotation.
Quotation
A quotation-ready inquiry states: nominal size and pressure rating, body and seat material preference, end connection, operation, and the service medium with temperature. Typical values on this page are benchmark reference ranges; the binding values are confirmed at quotation.
Sample & supply
Supply terms, order quantities and lead time are agreed per order β state the destination country and required schedule with the inquiry.
Storage & shipping
Store valves with seats and seals protected from UV, ozone and deformation, keep end-face protectors on until installation, and for elastomer- or PTFE-seated executions avoid prolonged outdoor storage β seat compounds age fastest in direct sunlight and freezing conditions.
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