{"id":658,"date":"2026-10-02T13:17:46","date_gmt":"2026-10-02T11:17:46","guid":{"rendered":"https:\/\/www.valfonta.com\/producto\/pressure-excess-valve-s2\/"},"modified":"2026-10-22T09:22:31","modified_gmt":"2026-10-22T07:22:31","slug":"pressure-excess-valve-s2","status":"publish","type":"product","link":"https:\/\/www.valfonta.com\/en\/product\/pressure-excess-valve-s2\/","title":{"rendered":"S2 excess pressure valve"},"content":{"rendered":"<div class=\"wp-block-group vf-raiz vf-pl-ficha-producto is-layout-flow wp-block-group-is-layout-flow\"><nav class=\"wp-block-group vf-breadcrumbs vfa-aria-label--Breadcrumbs is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><a href=\"\/en\/\">Home<\/a><span class=\"vf-sep\" aria-hidden=\"true\">\u203a<\/span><a href=\"https:\/\/www.valfonta.com\/en\/pressure-relief-valve\/\">Pressure relief valves<\/a><span class=\"vf-sep\" aria-hidden=\"true\">\u203a<\/span><span aria-current=\"page\">S2 excess pressure valve<\/span><\/p><\/nav><article class=\"wp-block-group vf-pdp vfd-model--S2 is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-pdp-hero is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-pdp-title is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-pdp-eyebrow wp-block-paragraph\">Excess pressure valve \u00b7 Diaphragm<\/p><h1 class=\"wp-block-heading\">S2 excess pressure valve<\/h1><\/div><div class=\"wp-block-group vf-pdp-media is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><span class=\"vf-pdp-badge\">Internal sensing<\/span><img decoding=\"async\" src=\"https:\/\/www.valfonta.com\/wp-content\/uploads\/2026\/10\/ok-M2-PROVISIONAL-700x700-1.jpg\" alt=\"Valfonta S2 excess pressure valve with diaphragm actuator and flanged connection\" class=\"wp-image-193\" width=\"700\" height=\"700\" fetchpriority=\"high\"><\/p><\/div><div class=\"wp-block-group vf-pdp-body is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-lead wp-block-paragraph\">Self-regulating, direct-acting excess pressure valve with a diaphragm actuator and internal pressure sensing. It holds the inlet pressure at the set maximum value, from 0.02 to 10 barg, on compressed air, gases, liquids, and low-temperature steam.<\/p><ul class=\"vf-pdp-keys wp-block-list\"><li><span>Sizes<\/span><b>DN15 to DN100<\/b><\/li><li><span>Pressure rating<\/span><b>PN16 to PN40 <small>Class 150 \u2013 300<\/small><\/b><\/li><li><span>Set pressure range<\/span><b>0.02 to 10 barg <small>up to 16 on request<\/small><\/b><\/li><li><span>Temperature<\/span><b>up to 180 \u00b0C <small>with PTFE and condensate pot<\/small><\/b><\/li><li><span>Kv<\/span><b>3.5 to 115 m\u00b3\/h<\/b><\/li><li><span>Pressure sensing point<\/span><b>Internal <small>external for steam<\/small><\/b><\/li><\/ul><div class=\"wp-block-group vf-pdp-cta is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><a class=\"vf-btn vf-btn--pri\" href=\"#solicitar\">Request a quote<\/a><a class=\"vf-btn vf-btn--sec\" href=\"\/wp-content\/uploads\/2026\/10\/S2-18A-ESP.pdf\" target=\"_blank\" rel=\"noopener\">Download datasheet <small>PDF<\/small><\/a><\/p><\/div><p class=\"vf-pdp-contact wp-block-paragraph\">Questions about set pressure or sizing? Call <a href=\"tel:+34933720888\">933 720 888<\/a> or email <a href=\"mailto:valfonta@valfonta.com\">valfonta@valfonta.com<\/a>.<\/p><\/div><\/div><ul class=\"vf-pdp-trust wp-block-list\"><li>In-house design and manufacturing in Badalona<\/li><li>ATEX II 2 GD marking for zones 1 and 21<\/li><li>Fabric-reinforced diaphragm<\/li><li>Recommended spare parts identified in the exploded view<\/li><\/ul><nav class=\"wp-block-group vf-pdp-nav vfa-aria-label--Datasheet%20contents is-layout-flow wp-block-group-is-layout-flow\"><ul class=\"wp-block-list\"><li><a href=\"#aplicaciones\">Applications<\/a><\/li><li><a href=\"#especificaciones\">Specifications<\/a><\/li><li><a href=\"#funcionamiento\">Operation<\/a><\/li><li><a href=\"#instalacion\">Installation<\/a><\/li><li><a href=\"#documentacion\">Documentation<\/a><\/li><li><a href=\"#comparar\">Compare<\/a><\/li><li><a href=\"#preguntas\">FAQ<\/a><\/li><li><a href=\"#solicitar\">Request a quote<\/a><\/li><\/ul><\/nav><section id=\"aplicaciones\" class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-pdp-two is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">What the S2 is used for<\/h2><p class=\"wp-block-paragraph\">The <strong>S2<\/strong> is an <a href=\"https:\/\/www.valfonta.com\/en\/pressure-relief-valve\/\">excess pressure valve<\/a> that holds the upstream pressure: while the inlet pressure is below the set value, it stays closed, and when the pressure exceeds it, the valve opens in proportion to the pressure rise to relieve the excess. It is direct-acting and needs no auxiliary power.<\/p><p class=\"wp-block-paragraph\">It comes as standard with <strong>internal pressure sensing<\/strong>, so on gases and liquids it needs no external control line. Its different actuators allow very low set pressures, from 0.02 barg. Learn more about <a href=\"https:\/\/www.valfonta.com\/en\/blog\/self-regulating-excess-pressure-valves\/\">self-regulating excess pressure valves<\/a>.<\/p><ul class=\"vf-pdp-apps wp-block-list\"><li><b>Pressure maintaining<\/b><span>Holds the upstream pressure at the set maximum value.<\/span><\/li><li><b>Feeding between zones<\/b><span>Lets a zone with excess pressure feed another lower-pressure zone without starving the main line.<\/span><\/li><li><b>Gas control<\/b><span>Especially suited to gases between \u221210 and +80 \u00b0C.<\/span><\/li><li><b>Compressed air and liquids<\/b><span>Proportional relief to a recycle or return line.<\/span><\/li><li><b>Low-temperature steam<\/b><span>With external pressure sensing and a condensate pot.<\/span><\/li><\/ul><\/div><aside class=\"wp-block-group vf-pdp-fit is-layout-flow wp-block-group-is-layout-flow\"><h3 class=\"wp-block-heading\">Choose the S2 if\u2026<\/h3><ul class=\"vf-si wp-block-list\"><li>You need low set pressures, from 0.02 barg.<\/li><li>You work with gases, compressed air, or liquids and prefer not to install a control line.<\/li><li>Your sizes range from DN15 to DN100.<\/li><li>The temperature does not exceed 180 \u00b0C.<\/li><\/ul><h3 class=\"wp-block-heading\">Choose another model if\u2026<\/h3><ul class=\"vf-no wp-block-list\"><li>You work with steam or liquids above 180 \u00b0C: the <a href=\"https:\/\/www.valfonta.com\/en\/product\/pressure-excess-valve-s1\/\">S1<\/a> and the <a href=\"https:\/\/www.valfonta.com\/en\/product\/pressure-relief-valve-s3\/\">S3<\/a> go up to 220 \u00b0C.<\/li><li>You need DN125 or DN150: see the <a href=\"https:\/\/www.valfonta.com\/en\/product\/pressure-excess-valve-s1\/\">S1<\/a> or the <a href=\"https:\/\/www.valfonta.com\/en\/product\/pressure-relief-valve-s3\/\">S3<\/a>.<\/li><li>Your set pressure is above 10 barg: the <a href=\"https:\/\/www.valfonta.com\/en\/product\/pressure-relief-valve-s3\/\">S3<\/a> goes up to 20 barg.<\/li><li>DN15 to DN25 in stainless steel is enough for you: see the <a href=\"https:\/\/www.valfonta.com\/en\/product\/excess-pressure-valve-model-prv55\/\">PRV55<\/a>, from 0.01 barg.<\/li><\/ul><\/aside><\/div><\/section><section id=\"especificaciones\" class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">S2 technical specifications<\/h2><div class=\"wp-block-group vf-tbl-wrap is-layout-flow wp-block-group-is-layout-flow\"><figure class=\"wp-block-table vf-tbl\"><table><tbody><tr><th scope=\"row\">Type<\/th><td>Self-regulating, direct-acting, with diaphragm actuator and seat balanced by a compensating plunger<\/td><\/tr><tr><th scope=\"row\">Sizes<\/th><td>DN15 to DN100<\/td><\/tr><tr><th scope=\"row\">Connections<\/th><td>EN PN16, PN25, and PN40 flanges \u00b7 ANSI 150 \/ 300 flanges \u00b7 BSP or NPT thread up to 2\u2033<\/td><\/tr><tr><th scope=\"row\">Pressure rating<\/th><td>PN16 \u2013 PN25 \u2013 PN40 \u00b7 ANSI Class 150 \u2013 Class 300<\/td><\/tr><tr><th scope=\"row\">Set pressure range<\/th><td>0.02 to 10 barg depending on actuator and spring (up to 16 barg on request)<\/td><\/tr><tr><th scope=\"row\">Maximum inlet pressure<\/th><td>10 barg (up to 16 barg on request)<\/td><\/tr><tr><th scope=\"row\">Maximum differential pressure<\/th><td>16 bar for DN15 to DN50<\/td><\/tr><tr><th scope=\"row\">Kv coefficient<\/th><td>From 3.5 m\u00b3\/h (DN15) to 115 m\u00b3\/h (DN100). Reduced Kv on request<\/td><\/tr><tr><th scope=\"row\">Temperature depending on diaphragm<\/th><td>NBR: \u221220 to 80 \u00b0C \u00b7 EPDM: \u221240 to 125 \u00b0C \u00b7 PTFE: up to 180 \u00b0C with condensate pot \u00b7 FKM: on request<\/td><\/tr><tr><th scope=\"row\">Temperature depending on seat<\/th><td>NBR: 80 \u00b0C \u00b7 EPDM: 125 \u00b0C \u00b7 FPM: 150 \u00b0C \u00b7 PTFE + graphite: 180 \u00b0C<\/td><\/tr><tr><th scope=\"row\">Body material<\/th><td>WCB (1.0619) carbon steel or CF3M (1.4408) stainless steel. On request: RG10 bronze, duplex, or super duplex<\/td><\/tr><tr><th scope=\"row\">Internals<\/th><td>Stainless steel AISI 316L<\/td><\/tr><tr><th scope=\"row\">Pressure sensing point<\/th><td>Internal as standard. External on request, required for steam and for liquids above 125 \u00b0C<\/td><\/tr><tr><th scope=\"row\">Special designs<\/th><td>Stainless steel actuator \u00b7 Reduced Kv \u00b7 Protective cap for the adjusting stem<\/td><\/tr><tr><th scope=\"row\">ATEX<\/th><td>II 2 GD c IIC Tx \/ c IIIC Tx\u00baC \u00b7 certificate LOM 14.034 U<\/td><\/tr><tr><th scope=\"row\">Pressure Equipment Directive<\/th><td>PED 2014\/68\/EU: the nameplate indicates whether CE marking is required<\/td><\/tr><\/tbody><\/table><\/figure><\/div><h3 class=\"wp-block-heading\">Dimensions and weight<\/h3><div class=\"wp-block-group vf-tbl-wrap is-layout-flow wp-block-group-is-layout-flow\"><figure class=\"wp-block-table vf-tbl vf-tbl--grid\"><table><thead><tr><th scope=\"col\"><\/th><th scope=\"col\">DN15<\/th><th scope=\"col\">DN20<\/th><th scope=\"col\">DN25<\/th><th scope=\"col\">DN32<\/th><th scope=\"col\">DN40<\/th><th scope=\"col\">DN50<\/th><th scope=\"col\">DN65<\/th><th scope=\"col\">DN80<\/th><th scope=\"col\">DN100<\/th><\/tr><\/thead><tbody><tr><th scope=\"row\">Kv (m\u00b3\/h)<\/th><td>3,5<\/td><td>5<\/td><td>9<\/td><td>13,5<\/td><td>22<\/td><td>32<\/td><td>57<\/td><td>82<\/td><td>115<\/td><\/tr><tr><th scope=\"row\">Length A (EN)<\/th><td>130<\/td><td>150<\/td><td>160<\/td><td>180<\/td><td>200<\/td><td>230<\/td><td>290<\/td><td>310<\/td><td>350<\/td><\/tr><tr><th scope=\"row\">Length A (ANSI 150)<\/th><td>\u2013<\/td><td>\u2013<\/td><td>184<\/td><td>\u2013<\/td><td>222<\/td><td>254<\/td><td>276<\/td><td>298,5<\/td><td>352,5<\/td><\/tr><tr><th scope=\"row\">Length A (ANSI 300)<\/th><td>\u2013<\/td><td>\u2013<\/td><td>197<\/td><td>\u2013<\/td><td>235<\/td><td>267<\/td><td>292<\/td><td>317,5<\/td><td>\u2013<\/td><\/tr><tr><th scope=\"row\">Height L<\/th><td>345<\/td><td>345<\/td><td>320<\/td><td>320<\/td><td>375<\/td><td>375<\/td><td>405<\/td><td>490<\/td><td>505<\/td><\/tr><tr><th scope=\"row\">Height L with cap<\/th><td>360<\/td><td>360<\/td><td>335<\/td><td>335<\/td><td>390<\/td><td>390<\/td><td>420<\/td><td>505<\/td><td>520<\/td><\/tr><tr><th scope=\"row\">Weight (kg)<\/th><td>20<\/td><td>20<\/td><td>22<\/td><td>23<\/td><td>25<\/td><td>28<\/td><td>43<\/td><td>53<\/td><td>60<\/td><\/tr><\/tbody><\/table><\/figure><\/div><p class=\"vf-note wp-block-paragraph\">Dimensions in millimeters. Dimensioned drawings in the PDF datasheet.<\/p><h3 class=\"wp-block-heading\">Set pressure ranges and actuator diameter (mm)<\/h3><div class=\"wp-block-group vf-tbl-wrap is-layout-flow wp-block-group-is-layout-flow\"><figure class=\"wp-block-table vf-tbl vf-tbl--grid\"><table><thead><tr><th scope=\"col\">Range (barg)<\/th><th scope=\"col\">DN15 and DN20<\/th><th scope=\"col\">DN25 and DN32<\/th><th scope=\"col\">DN40 and DN50<\/th><th scope=\"col\">DN65<\/th><th scope=\"col\">DN80<\/th><th scope=\"col\">DN100<\/th><\/tr><\/thead><tbody><tr><th scope=\"row\">0,02 \u2013 0,05<\/th><td>350<\/td><td>350<\/td><td>\u2013<\/td><td>\u2013<\/td><td>\u2013<\/td><td>\u2013<\/td><\/tr><tr><th scope=\"row\">0,03 \u2013 0,1<\/th><td>295<\/td><td>295<\/td><td>350<\/td><td>350<\/td><td>\u2013<\/td><td>\u2013<\/td><\/tr><tr><th scope=\"row\">0,1 \u2013 1<\/th><td>295<\/td><td>295<\/td><td>295<\/td><td>295<\/td><td>295<\/td><td>295<\/td><\/tr><tr><th scope=\"row\">0,2 \u2013 2<\/th><td>230<\/td><td>230<\/td><td>230<\/td><td>230<\/td><td>295<\/td><td>295<\/td><\/tr><tr><th scope=\"row\">1,5 \u2013 4<\/th><td>\u2013<\/td><td>\u2013<\/td><td>\u2013<\/td><td>175<\/td><td>230<\/td><td>230<\/td><\/tr><tr><th scope=\"row\">1 \u2013 6<\/th><td>175<\/td><td>175<\/td><td>175<\/td><td>\u2013<\/td><td>\u2013<\/td><td>\u2013<\/td><\/tr><tr><th scope=\"row\">3 \u2013 6<\/th><td>\u2013<\/td><td>\u2013<\/td><td>\u2013<\/td><td>175<\/td><td>230<\/td><td>230<\/td><\/tr><tr><th scope=\"row\">3 \u2013 10<\/th><td>175<\/td><td>175<\/td><td>175<\/td><td>\u2013<\/td><td>\u2013<\/td><td>\u2013<\/td><\/tr><tr><th scope=\"row\">4 \u2013 12<\/th><td>175<\/td><td>175<\/td><td>175<\/td><td>\u2013<\/td><td>\u2013<\/td><td>\u2013<\/td><\/tr><\/tbody><\/table><\/figure><\/div><details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>Exploded view and materials (20 parts)<\/summary><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-tbl-wrap is-layout-flow wp-block-group-is-layout-flow\"><figure class=\"wp-block-table vf-tbl vf-tbl--grid\"><table><thead><tr><th scope=\"col\">No.<\/th><th scope=\"col\">Part<\/th><th scope=\"col\">Material<\/th><\/tr><\/thead><tbody><tr><th scope=\"row\">1<\/th><td>Body<\/td><td>1.0619 (WCB) carbon steel \u00b7 1.4408 (CF3M) stainless \u00b7 RG10 bronze<\/td><\/tr><tr><th scope=\"row\">2, 3, 30<\/th><td>Bushing and seat holders<\/td><td>1.4404 (316L) stainless<\/td><\/tr><tr><th scope=\"row\">4<\/th><td>Screws<\/td><td>Steel 8.8 or A2-70 stainless<\/td><\/tr><tr><th scope=\"row\">5<\/th><td>Gasket<\/td><td>PTFE<\/td><\/tr><tr><th scope=\"row\">6, 7, 14, 16, 20, 29<\/th><td>Screws, nuts, and lock washer<\/td><td>A2-70 stainless<\/td><\/tr><tr><th scope=\"row\">8, 21<\/th><td>Upper and lower actuator<\/td><td>Steel sheet 1.0335 with epoxy paint or AISI 316L stainless<\/td><\/tr><tr><th scope=\"row\">9<\/th><td>Spring support<\/td><td>Galvanized steel sheet 1.0035<\/td><\/tr><tr><th scope=\"row\">10<\/th><td>Adjusting spring<\/td><td>Steel 52SiCrNi5 with epoxy<\/td><\/tr><tr><th scope=\"row\">11<\/th><td>Adjusting nut<\/td><td>Galvanized steel 8.8<\/td><\/tr><tr><th scope=\"row\">12<\/th><td>Bearing<\/td><td>PTFE + graphite<\/td><\/tr><tr><th scope=\"row\">13, 18<\/th><td>Adjusting stem and stem<\/td><td>1.4404 (316L) stainless<\/td><\/tr><tr><th scope=\"row\">15<\/th><td>O-ring<\/td><td>NBR, FKM, or EPDM<\/td><\/tr><tr><th scope=\"row\">19<\/th><td>Diaphragm<\/td><td>NBR, EPDM, or FKM (PTFE optional)<\/td><\/tr><tr><th scope=\"row\">22, 23, 27<\/th><td>Lower diaphragm plate, plunger guide, and bonnet<\/td><td>1.4404 (316L) stainless<\/td><\/tr><tr><th scope=\"row\">24<\/th><td>Cover<\/td><td>Galvanized steel 1.1141<\/td><\/tr><tr><th scope=\"row\">25<\/th><td>Gasket<\/td><td>Graphite<\/td><\/tr><tr><th scope=\"row\">26<\/th><td>Balancing plunger<\/td><td>NBR, FKM, EPDM, or PTFE + graphite<\/td><\/tr><tr><th scope=\"row\">28<\/th><td>Seat<\/td><td>NBR, FKM, EPDM, or PTFE + graphite<\/td><\/tr><tr><th scope=\"row\">41, 43, 44<\/th><td>Lower bushing stem, washer, and screws (DN100)<\/td><td>316L and A2-70 stainless<\/td><\/tr><tr><th scope=\"row\">42<\/th><td>O-ring (DN100)<\/td><td>NBR, FKM, or EPDM<\/td><\/tr><\/tbody><\/table><\/figure><\/div><\/div><\/details><details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>Recommended spare parts<\/summary><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-tbl-wrap is-layout-flow wp-block-group-is-layout-flow\"><figure class=\"wp-block-table vf-tbl vf-tbl--grid\"><table><thead><tr><th scope=\"col\">Reference<\/th><th scope=\"col\">Description<\/th><th scope=\"col\">Parts<\/th><\/tr><\/thead><tbody><tr><th scope=\"row\">\u2014<\/th><td>Diaphragm<\/td><td>19<\/td><\/tr><tr><th scope=\"row\">\u2014<\/th><td>Seat and compensating plunger<\/td><td>26 and 28<\/td><\/tr><tr><th scope=\"row\">\u2014<\/th><td>Gaskets and O-rings<\/td><td>5, 15, 25, and 42 (DN100)<\/td><\/tr><tr><th scope=\"row\">\u2014<\/th><td>Bearing<\/td><td>12<\/td><\/tr><\/tbody><\/table><\/figure><\/div><\/div><\/details><\/section><section id=\"funcionamiento\" class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">How the S2 works<\/h2><p class=\"wp-block-paragraph\">The S2 balances the inlet pressure acting on the diaphragm against the force of the adjusting spring.<\/p><ol class=\"vf-steps wp-block-list\"><li><b>Sensing.<\/b> The inlet pressure (p1) reaches the actuator through the internal sensing port or, on request, through an external sensing point.<\/li><li><b>Valve closed.<\/b> As long as the force of that pressure is lower than the spring force, the plug stays on the seat.<\/li><li><b>Proportional opening.<\/b> When the pressure exceeds it, the valve opens in proportion to the pressure rise and relieves the excess fluid.<\/li><li><b>Balanced seat.<\/b> The compensating plunger balances the forces acting on the seat, and the spring closes the valve again when the pressure drops.<\/li><li><b>Set pressure.<\/b> The spring force is adjusted with the adjusting stem (13).<\/li><\/ol><p class=\"wp-block-paragraph\">It must never be used as a safety accessory. If the installation needs overpressure protection, also install one of our <a href=\"https:\/\/www.valfonta.com\/en\/safety-valves\/\">safety valves<\/a>.<\/p><\/section><section id=\"instalacion\" class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">S2 installation<\/h2><p class=\"wp-block-paragraph\">The manufacturer\u2019s recommended layout installs the S2 on a branch off the main line, between isolation valves and with a strainer, discharging the excess to a recycle line. A pressure gauge lets you check the inlet pressure.<\/p><div class=\"wp-block-group vf-diagram vf-s-7307c0 vf-t-figure is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-svgw is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><svg viewbox=\"0 0 900 240\" role=\"img\" aria-label=\"Installation diagram of a pressure relief or excess pressure valve on a branch line\"><path d=\"M20 90 H880\" stroke=\"#9aa0a6\" stroke-width=\"6\" fill=\"none\"><\/path><path d=\"M865 90 l14 0 -10 -7 m10 7 -10 7\" stroke=\"#1e2123\" stroke-width=\"3\" fill=\"none\"><\/path><rect x=\"60\" y=\"62\" width=\"90\" height=\"56\" rx=\"4\" fill=\"#fff\" stroke=\"#1e2123\" stroke-width=\"2\"><\/rect><circle cx=\"105\" cy=\"90\" r=\"16\" fill=\"none\" stroke=\"#1e2123\" stroke-width=\"2\"><\/circle><path d=\"M97 90 l18 0\" stroke=\"#1e2123\" stroke-width=\"2\"><\/path><path d=\"M420 90 V150\" stroke=\"#9aa0a6\" stroke-width=\"5\"><\/path><rect x=\"385\" y=\"150\" width=\"70\" height=\"46\" rx=\"4\" fill=\"#fdecf1\" stroke=\"#e6305d\" stroke-width=\"2\"><\/rect><path d=\"M420 160 v24 m-7 -8 7 8 7 -8\" stroke=\"#e6305d\" stroke-width=\"2.5\" fill=\"none\"><\/path><path d=\"M455 173 H640 V215\" stroke=\"#9aa0a6\" stroke-width=\"5\" fill=\"none\"><\/path><path d=\"M632 205 l8 12 8 -12\" stroke=\"#1e2123\" stroke-width=\"2.5\" fill=\"none\"><\/path><g><circle cx=\"300\" cy=\"51\" r=\"13\" fill=\"#fff\" stroke=\"#1e2123\" stroke-width=\"2\"><\/circle><line x1=\"300\" y1=\"64\" x2=\"300\" y2=\"90\" stroke=\"#1e2123\" stroke-width=\"2\"><\/line><line x1=\"300\" y1=\"51\" x2=\"307\" y2=\"44\" stroke=\"#e6305d\" stroke-width=\"2\"><\/line><\/g><rect x=\"720\" y=\"65\" width=\"110\" height=\"50\" rx=\"4\" fill=\"#fff\" stroke=\"#1e2123\" stroke-width=\"2\"><\/rect><circle cx=\"105\" cy=\"138\" r=\"11\" fill=\"#1e2123\"><\/circle><text x=\"105\" y=\"142\" font-size=\"12\" font-weight=\"700\" fill=\"#fff\" text-anchor=\"middle\" font-family=\"Montserrat,Arial\">1<\/text><circle cx=\"324\" cy=\"38\" r=\"11\" fill=\"#1e2123\"><\/circle><text x=\"324\" y=\"42\" font-size=\"12\" font-weight=\"700\" fill=\"#fff\" text-anchor=\"middle\" font-family=\"Montserrat,Arial\">2<\/text><circle cx=\"420\" cy=\"218\" r=\"11\" fill=\"#e6305d\"><\/circle><text x=\"420\" y=\"222\" font-size=\"12\" font-weight=\"700\" fill=\"#fff\" text-anchor=\"middle\" font-family=\"Montserrat,Arial\">3<\/text><circle cx=\"640\" cy=\"232\" r=\"11\" fill=\"#1e2123\"><\/circle><text x=\"640\" y=\"236\" font-size=\"12\" font-weight=\"700\" fill=\"#fff\" text-anchor=\"middle\" font-family=\"Montserrat,Arial\">4<\/text><circle cx=\"775\" cy=\"136\" r=\"11\" fill=\"#1e2123\"><\/circle><text x=\"775\" y=\"140\" font-size=\"12\" font-weight=\"700\" fill=\"#fff\" text-anchor=\"middle\" font-family=\"Montserrat,Arial\">5<\/text><\/svg><\/p><\/div><div class=\"wp-block-group vf-t-figcaption is-layout-flow wp-block-group-is-layout-flow\"><ol class=\"wp-block-list\"><li>Main line (pump or equipment generating the pressure)<\/li><li>Inlet pressure gauge<\/li><li>S2 excess pressure valve, with isolation valves and strainer<\/li><li>Discharge to recycle or return<\/li><li>Point of use<\/li><\/ol><\/div><\/div><h3 class=\"wp-block-heading\">Installation and start-up<\/h3><ol class=\"vf-steps wp-block-list\"><li><b>Clean the pipe and install a strainer<\/b> at the inlet: it protects the seat and reduces maintenance.<\/li><li><b>Follow the arrow on the body<\/b> and install the valve in a horizontal pipe (with a slight slope if condensate is present).<\/li><li><b>Mounting position:<\/b> use the standard position in the manual for any fluid above 0 \u00b0C; the alternative position is only suitable for gases and liquids up to 80 \u00b0C. Other positions are not recommended.<\/li><li><b>Support the pipe, not the valve<\/b> or the actuator: place supports close to the flanges.<\/li><li><b>Control port:<\/b> with steam or liquids above 125 \u00b0C, order the valve with external sensing and connect it to the inlet, at least 1 m away (10 \u00d7 DN), using 10 \u00d7 1 mm tubing. If the pressure fluctuates, add a needle valve.<\/li><li><b>Condensate pot<\/b> for steam and liquids above 125 \u00b0C: at the highest point and filled until it overflows.<\/li><li><b>Start up slowly:<\/b> open the isolation valves gradually to avoid water hammer.<\/li><li><b>Adjust the set pressure<\/b> with the adjusting stem (Valfonta supplies the valve preset). Compressing the spring (turning clockwise) raises the set pressure. Check it on the inlet pressure gauge.<\/li><\/ol><p class=\"wp-block-paragraph\">If the pressure fluctuates, check the sensing point and the sizing (Kvs, size, or actuator). We can help you with relief valve set pressure and with <a href=\"https:\/\/www.valfonta.com\/en\/blog\/chattering-in-pressure-relief-valves\/\">relief valve chattering<\/a>.<\/p><\/section><section id=\"documentacion\" class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">S2 technical documentation<\/h2><div class=\"wp-block-group vf-docs is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-doc vf-amb-enllac is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><i>PDF<\/i><\/p><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><b>S2 datasheet<\/b><span>PDF \u00b7 5 pages \u00b7 features, exploded view, dimensions, and installation<\/span><\/p><\/div><p class=\"vf-enllac wp-block-paragraph\"><a class=\"vf-enllac-estirat\" href=\"\/wp-content\/uploads\/2026\/10\/S2-18A-ESP.pdf\" aria-label=\"PDF S2 datasheet PDF \u00b7 5 pages \u00b7 features, exploded view, dimensions, and installation\" target=\"_blank\" rel=\"noopener\"><\/a><\/p><\/div><div class=\"wp-block-group vf-doc vf-amb-enllac is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><i>PDF<\/i><\/p><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><b>Operation, installation, and maintenance manual<\/b><span>PDF \u00b7 16 pages \u00b7 installation, ATEX, troubleshooting, and receiving<\/span><\/p><\/div><p class=\"vf-enllac wp-block-paragraph\"><a class=\"vf-enllac-estirat\" href=\"\/wp-content\/uploads\/2026\/10\/Manual-S2-18A-ESP.pdf\" aria-label=\"PDF Operation, installation, and maintenance manual PDF \u00b7 16 pages \u00b7 installation, ATEX, troubleshooting, and receiving\" target=\"_blank\" rel=\"noopener\"><\/a><\/p><\/div><\/div><p class=\"wp-block-paragraph\">To order spare parts, give the serial number (S\/N) shown on the nameplate. Order certificates: see our <a href=\"https:\/\/www.valfonta.com\/en\/certificates\/\">quality certificates<\/a>.<\/p><\/section><section id=\"comparar\" class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">S2 vs. other excess pressure valves<\/h2><p class=\"wp-block-paragraph\">The range covers DN15 to DN150 and set pressures from 0.01 to 20 barg.<\/p><div class=\"wp-block-group vf-tbl-wrap is-layout-flow wp-block-group-is-layout-flow\"><figure class=\"wp-block-table vf-tbl vf-tbl--grid\"><table><thead><tr><th scope=\"col\">Model<\/th><th scope=\"col\">DN<\/th><th scope=\"col\">PN<\/th><th scope=\"col\">Set pressure (barg)<\/th><th scope=\"col\">Max. T (\u00b0C)<\/th><th scope=\"col\">Steam<\/th><th scope=\"col\">Standard body<\/th><\/tr><\/thead><tbody><tr><th scope=\"row\"><a href=\"https:\/\/www.valfonta.com\/en\/product\/pressure-excess-valve-prv53\/\">PRV53<\/a><\/th><td>15 \u2013 25<\/td><td>25<\/td><td>0,5 \u2013 15<\/td><td>150<\/td><td>No<\/td><td>CF3M stainless<\/td><\/tr><tr><th scope=\"row\"><a href=\"https:\/\/www.valfonta.com\/en\/product\/pressure-excess-valve-prv54\/\">PRV54<\/a><\/th><td>15 \u2013 25<\/td><td>25<\/td><td>0,5 \u2013 12<\/td><td>210<\/td><td>Yes<\/td><td>CF3M stainless<\/td><\/tr><tr><th scope=\"row\"><a href=\"https:\/\/www.valfonta.com\/en\/product\/excess-pressure-valve-model-prv55\/\">PRV55<\/a><\/th><td>15 \u2013 25<\/td><td>25<\/td><td>0,01 \u2013 8<\/td><td>150<\/td><td>Yes<\/td><td>CF3M stainless<\/td><\/tr><tr><th scope=\"row\"><a href=\"https:\/\/www.valfonta.com\/en\/product\/pressure-excess-valve-s1\/\">S1<\/a><\/th><td>15 \u2013 150<\/td><td>40<\/td><td>0,5 \u2013 15<\/td><td>220<\/td><td>Yes<\/td><td>Carbon steel or CF3M stainless<\/td><\/tr><tr><th scope=\"row\"><span class=\"vf-dato vf-dato-fila\" hidden data-vf-class=\"vf-cur\"><\/span>S2<\/th><td>15 \u2013 100<\/td><td>40<\/td><td>0,02 \u2013 10<\/td><td>180<\/td><td>Yes<\/td><td>Carbon steel or CF3M stainless<\/td><\/tr><tr><th scope=\"row\"><a href=\"https:\/\/www.valfonta.com\/en\/product\/pressure-relief-valve-s3\/\">S3<\/a><\/th><td>15 \u2013 150<\/td><td>40<\/td><td>0,5 \u2013 20<\/td><td>220<\/td><td>Yes<\/td><td>Carbon steel or CF3M stainless<\/td><\/tr><tr><th scope=\"row\">S4<\/th><td>15 \u2013 100<\/td><td>40<\/td><td>0,5 \u2013 20<\/td><td>220<\/td><td>Yes<\/td><td>Carbon steel or CF3M stainless<\/td><\/tr><\/tbody><\/table><\/figure><\/div><p class=\"vf-note wp-block-paragraph\">Data from the Valfonta summary catalog (2025); S2 set pressure from its datasheet. All accept water, oil, air, and non-flammable gases.<\/p><\/section><section id=\"preguntas\" class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">Frequently asked questions about the S2<\/h2><details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>Is the S2 a safety valve?<\/summary><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"wp-block-paragraph\">No. It is a pressure accessory that relieves excess pressure proportionally. If the installation needs overpressure protection, a <a href=\"https:\/\/www.valfonta.com\/en\/safety-valves\/\">safety valve<\/a> must also be installed.<\/p><\/div><\/details><details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>Does it need an external control line?<\/summary><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"wp-block-paragraph\">No, it comes with internal pressure sensing as standard. External sensing is only needed with steam or with liquids above 125 \u00b0C, connected at least 1 m from the inlet, or if specifically requested.<\/p><\/div><\/details><details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>Can it be used with steam?<\/summary><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"wp-block-paragraph\">Yes, with low-temperature steam. It must be ordered with external pressure sensing and a condensate pot, which protects the diaphragm from overheating. With a PTFE diaphragm and a condensate pot it works up to 180 \u00b0C.<\/p><\/div><\/details><details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>What set pressure does it accept?<\/summary><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"wp-block-paragraph\">From 0.02 to 10 barg, depending on actuator and spring; up to 16 barg on request. For 0.02 to 0.05 barg, the 350 mm actuator is used (DN15 to DN32).<\/p><\/div><\/details><details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>What maintenance does it need?<\/summary><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><p class=\"wp-block-paragraph\">Periodically check the gaskets and wear parts; the frequency depends on the operating conditions. This can be done with the valve installed, depressurized, and isolated, and only with genuine spare parts.<\/p><\/div><\/details><\/section><section id=\"relacionados\" class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">Other excess pressure valve models<\/h2><ul class=\"vf-rel wp-block-list\"><li><a href=\"https:\/\/www.valfonta.com\/en\/product\/pressure-excess-valve-s1\/\"><img decoding=\"async\" src=\"https:\/\/www.valfonta.com\/wp-content\/uploads\/2026\/10\/ok-M1-S1-3D.jpg\" alt=\"S1 excess pressure valve\" class=\"wp-image-205\" width=\"300\" height=\"300\" loading=\"lazy\"><b>S1 excess pressure valve<\/b><span>Diaphragm and bellows, up to DN150 and 220 \u00b0C.<\/span><\/a><\/li><li><a href=\"https:\/\/www.valfonta.com\/en\/product\/pressure-relief-valve-s3\/\"><img decoding=\"async\" src=\"https:\/\/www.valfonta.com\/wp-content\/uploads\/2026\/10\/valvula-alivio-presion-s3-s4-perspectiva-400.webp\" alt=\"S3 relief valve\" class=\"wp-image-10230\" width=\"300\" height=\"300\" loading=\"lazy\"><b>S3 relief valve<\/b><span>Spring-loaded, up to DN150 and 20 barg set pressure.<\/span><\/a><\/li><li><a href=\"https:\/\/www.valfonta.com\/en\/product\/pressure-excess-valve-prv53\/\"><img decoding=\"async\" src=\"https:\/\/www.valfonta.com\/wp-content\/uploads\/2026\/10\/ok-PRV30-44.jpg\" alt=\"PRV53 excess pressure valve\" class=\"wp-image-207\" width=\"300\" height=\"300\" loading=\"lazy\"><b>PRV53 excess pressure valve<\/b><span>CF3M stainless, DN15 to DN25, set pressure from 0.5 to 15 barg.<\/span><\/a><\/li><li><a href=\"https:\/\/www.valfonta.com\/en\/product\/pressure-excess-valve-prv54\/\"><img decoding=\"async\" src=\"https:\/\/www.valfonta.com\/wp-content\/uploads\/2026\/10\/ok-PRV30-44.jpg\" alt=\"PRV54 excess pressure valve\" class=\"wp-image-207\" width=\"300\" height=\"300\" loading=\"lazy\"><b>PRV54 excess pressure valve<\/b><span>CF3M stainless, DN15 to DN25, steam up to 210 \u00b0C.<\/span><\/a><\/li><li><a href=\"https:\/\/www.valfonta.com\/en\/product\/excess-pressure-valve-model-prv55\/\"><img decoding=\"async\" src=\"https:\/\/www.valfonta.com\/wp-content\/uploads\/2026\/10\/ok-PRV45-55.jpg\" alt=\"PRV55 excess pressure valve\" class=\"wp-image-208\" width=\"300\" height=\"300\" loading=\"lazy\"><b>PRV55 excess pressure valve<\/b><span>Set pressures from 0.01 barg, DN15 to DN25.<\/span><\/a><\/li><\/ul><\/section><section id=\"solicitar\" class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group vf-quote is-layout-flow wp-block-group-is-layout-flow\"><div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\"><h2 class=\"wp-block-heading\">Request a quote for the S2<\/h2><p class=\"wp-block-paragraph\">Give us your installation details and we will recommend the right size, Kv, actuator, and diaphragm for your set pressure.<\/p><ul class=\"wp-block-list\"><li>Fluid and operating temperature<\/li><li>Set pressure and normal operating pressure<\/li><li>Flow rate the valve must discharge<\/li><li>Size, body material, and connection type<\/li><\/ul><p class=\"vf-pdp-contact wp-block-paragraph\">You can also call <a href=\"tel:+34933720888\">933 720 888<\/a>.<\/p><\/div>\n<div class=\"wpcf7 no-js\" id=\"wpcf7-f558-o1\" lang=\"en-US\" dir=\"ltr\" data-wpcf7-id=\"558\">\n<div class=\"screen-reader-response\"><p role=\"status\" aria-live=\"polite\" aria-atomic=\"true\"><\/p> <ul><\/ul><\/div>\n<form action=\"\/en\/wp-json\/wp\/v2\/product\/658#wpcf7-f558-o1\" method=\"post\" class=\"wpcf7-form init vf-form wpcf7-acceptance-as-validation\" aria-label=\"Contact form\" novalidate=\"novalidate\" data-status=\"init\" toolname=\"solicitar_oferta\" tooldescription=\"Request a quote from Valfonta for the models on this page (model, size, fluid and pressures); a member of the team will reply.\">\n<fieldset class=\"hidden-fields-container\"><input type=\"hidden\" name=\"_wpcf7\" value=\"558\" \/><input type=\"hidden\" name=\"_wpcf7_version\" value=\"6.2.3\" \/><input type=\"hidden\" name=\"_wpcf7_locale\" value=\"en_US\" \/><input type=\"hidden\" name=\"_wpcf7_unit_tag\" value=\"wpcf7-f558-o1\" \/><input type=\"hidden\" name=\"_wpcf7_container_post\" value=\"0\" \/><input type=\"hidden\" name=\"_wpcf7_posted_data_hash\" value=\"\" \/><input type=\"hidden\" name=\"_vf_t\" value=\"1792698943.a677e3f00a8b9796\" \/>\n<\/fieldset>\n<input class=\"wpcf7-form-control wpcf7-hidden\" value=\"S2\" type=\"hidden\" name=\"modelo\" \/><label>Name *<span class=\"wpcf7-form-control-wrap\" data-name=\"nombre\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-text wpcf7-validates-as-required\" autocomplete=\"name\" aria-required=\"true\" aria-invalid=\"false\" value=\"\" type=\"text\" name=\"nombre\" \/><\/span><\/label><label>Company<span class=\"wpcf7-form-control-wrap\" data-name=\"empresa\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-text\" autocomplete=\"organization\" aria-invalid=\"false\" value=\"\" type=\"text\" name=\"empresa\" \/><\/span><\/label><label>Email *<span class=\"wpcf7-form-control-wrap\" data-name=\"email\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-email wpcf7-validates-as-required wpcf7-text wpcf7-validates-as-email\" autocomplete=\"email\" aria-required=\"true\" aria-invalid=\"false\" value=\"\" type=\"email\" name=\"email\" \/><\/span><\/label><label>Phone<span class=\"wpcf7-form-control-wrap\" data-name=\"telefono\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-tel wpcf7-text wpcf7-validates-as-tel\" autocomplete=\"tel\" aria-invalid=\"false\" value=\"\" type=\"tel\" name=\"telefono\" \/><\/span><\/label><fieldset><legend>Application data (optional)<\/legend><label>Size<span class=\"wpcf7-form-control-wrap\" data-name=\"dn\"><select class=\"wpcf7-form-control wpcf7-select\" aria-invalid=\"false\" name=\"dn\"><option value=\"\">Select<\/option><option value=\"DN15 (\u00bd\u2033)\">DN15 (\u00bd\u2033)<\/option><option value=\"DN20 (\u00be\u2033)\">DN20 (\u00be\u2033)<\/option><option value=\"DN25 (1\u2033)\">DN25 (1\u2033)<\/option><option value=\"DN32 (1\u00bc\u2033)\">DN32 (1\u00bc\u2033)<\/option><option value=\"DN40 (1\u00bd\u2033)\">DN40 (1\u00bd\u2033)<\/option><option value=\"DN50 (2\u2033)\">DN50 (2\u2033)<\/option><option value=\"DN65\">DN65<\/option><option value=\"DN80\">DN80<\/option><option value=\"DN100\">DN100<\/option><option value=\"I don&#039;t know\">I don&#039;t know<\/option><\/select><\/span><\/label><label>Fluid<span class=\"wpcf7-form-control-wrap\" data-name=\"fluido\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-text\" aria-invalid=\"false\" placeholder=\"compressed air, gas, water\u2026\" value=\"\" type=\"text\" name=\"fluido\" \/><\/span><\/label><label>Set pressure (barg)<span class=\"wpcf7-form-control-wrap\" data-name=\"tarado\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-text\" aria-invalid=\"false\" value=\"\" type=\"text\" name=\"tarado\" \/><\/span><\/label><label>Operating pressure (barg)<span class=\"wpcf7-form-control-wrap\" data-name=\"p_servicio\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-text\" aria-invalid=\"false\" value=\"\" type=\"text\" name=\"p_servicio\" \/><\/span><\/label><label>Flow rate to discharge<span class=\"wpcf7-form-control-wrap\" data-name=\"caudal\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-text\" aria-invalid=\"false\" placeholder=\"e.g. 50 Nm\u00b3\/h or 5 m\u00b3\/h\" value=\"\" type=\"text\" name=\"caudal\" \/><\/span><\/label><label>Temperature (\u00b0C)<span class=\"wpcf7-form-control-wrap\" data-name=\"temperatura\"><input size=\"40\" maxlength=\"400\" class=\"wpcf7-form-control wpcf7-text\" aria-invalid=\"false\" value=\"\" type=\"text\" name=\"temperatura\" \/><\/span><\/label><\/fieldset><label class=\"vf-full\">Message<span class=\"wpcf7-form-control-wrap\" data-name=\"mensaje\"><textarea cols=\"40\" rows=\"4\" maxlength=\"2000\" class=\"wpcf7-form-control wpcf7-textarea\" aria-invalid=\"false\" name=\"mensaje\"><\/textarea><\/span><\/label><label class=\"vf-chk vf-full\"><span class=\"wpcf7-form-control-wrap\" data-name=\"privacidad\"><span class=\"wpcf7-form-control wpcf7-acceptance\"><span class=\"wpcf7-list-item\"><input type=\"checkbox\" name=\"privacidad\" value=\"1\" aria-invalid=\"false\" \/><\/span><\/span><\/span> <span>I have read and accept the <a href=\"\/en\/privacy-policy\/\">privacy policy<\/a> *<\/span><\/label><input class=\"wpcf7-form-control wpcf7-submit has-spinner vf-btn vf-btn--pri\" type=\"submit\" value=\"Send request\" \/><span class=\"vf-hp\" aria-hidden=\"true\"><label>Web <input type=\"text\" name=\"vf_web\" value=\"\" tabindex=\"-1\" autocomplete=\"off\" toolparamdescription=\"Campo de control: d\u00e9jalo vac\u00edo\"><\/label><\/span><div class=\"wpcf7-response-output\" aria-hidden=\"true\"><\/div>\n<\/form>\n<\/div>\n\n<\/div><\/section><div class=\"wp-block-group vf-pdp-bar is-layout-flow wp-block-group-is-layout-flow\"><p class=\"vf-envolt wp-block-paragraph\"><a class=\"vf-btn vf-btn--sec\" href=\"tel:+34933720888\">Call<\/a><a class=\"vf-btn vf-btn--pri\" href=\"#solicitar\">Request a quote<\/a><\/p><\/div><\/article><\/div>","protected":false},"excerpt":{"rendered":"<p>Home\u203aPressure relief valves\u203aS2 excess pressure valve Excess pressure valve \u00b7 Diaphragm S2 excess pressure valve Internal sensing Self-regulating, direct-acting excess pressure valve with a diaphragm actuator and internal pressure sensing. It holds the inlet pressure at the set maximum value, from 0.02 to 10 barg, on compressed air, gases, liquids, and low-temperature steam. Request a ... <a title=\"S2 excess pressure valve\" class=\"read-more\" href=\"https:\/\/www.valfonta.com\/en\/product\/pressure-excess-valve-s2\/\" aria-label=\"Read more about S2 excess pressure valve\">Read more<\/a><\/p>\n","protected":false},"featured_media":0,"template":"","meta":{"_acf_changed":false,"_generate-full-width-content":"true","_generate-disable-headline":"true","rank_math_title":"S2 diaphragm excess pressure valve | Valfonta","rank_math_description":"Direct-acting S2 diaphragm excess pressure valve with internal sensing. DN15 to DN100, set pressure 0.02 to 10 barg, up to 180 \u00b0C with condensate pot.","rank_math_focus_keyword":"","vf_jsonld":"[{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Organization\",\"@id\":\"https:\/\/www.valfonta.com\/#organization\",\"name\":\"Valfonta\",\"legalName\":\"Val Fonta, S.L.\",\"taxID\":\"B59935718\",\"url\":\"https:\/\/www.valfonta.com\/en\/\",\"logo\":{\"@type\":\"ImageObject\",\"url\":\"https:\/\/www.valfonta.com\/wp-content\/uploads\/2026\/10\/valfonta-logo.webp\"},\"foundingDate\":\"1962\",\"email\":\"valfonta@valfonta.com\",\"telephone\":\"+34 933 720 888\",\"address\":{\"@type\":\"PostalAddress\",\"streetAddress\":\"C\/ Bronze 26, Pol. Ind. Les Guixeres\",\"postalCode\":\"08915\",\"addressLocality\":\"Badalona\",\"addressRegion\":\"Barcelona\",\"addressCountry\":\"ES\"},\"description\":\"Design, manufacture, and sale of pressure reducing valves, pressure relief valves, and control valves.\"},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.valfonta.com\/#website\",\"url\":\"https:\/\/www.valfonta.com\/en\/\",\"name\":\"Valfonta\",\"publisher\":{\"@id\":\"https:\/\/www.valfonta.com\/#organization\"},\"inLanguage\":\"en\"},{\"@type\":\"ItemPage\",\"@id\":\"https:\/\/www.valfonta.com\/en\/product\/pressure-excess-valve-s2\/#webpage\",\"url\":\"https:\/\/www.valfonta.com\/en\/product\/pressure-excess-valve-s2\/\",\"name\":\"S2 diaphragm excess pressure valve | Valfonta\",\"description\":\"Direct-acting S2 diaphragm excess pressure valve with internal sensing. 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It holds the inlet pressure at the set maximum value, from 0.02 to 10 barg, on compressed air, gases, liquids, and low-temperature steam.\",\"brand\":{\"@type\":\"Brand\",\"name\":\"Valfonta\"},\"manufacturer\":{\"@id\":\"https:\/\/www.valfonta.com\/#organization\"},\"model\":\"S2\",\"image\":\"https:\/\/www.valfonta.com\/wp-content\/uploads\/2026\/10\/ok-M2-PROVISIONAL-700x700-1.jpg\",\"material\":\"Carbon steel WCB or stainless steel CF3M\",\"additionalProperty\":[{\"@type\":\"PropertyValue\",\"name\":\"Type\",\"value\":\"Self-regulating, direct-acting, with diaphragm actuator and seat balanced by a compensating plunger\"},{\"@type\":\"PropertyValue\",\"name\":\"Sizes\",\"value\":\"DN15 to DN100\"},{\"@type\":\"PropertyValue\",\"name\":\"Connections\",\"value\":\"EN PN16, PN25, and PN40 flanges \u00b7 ANSI 150 \/ 300 flanges \u00b7 BSP or NPT thread up to 2\u2033\"},{\"@type\":\"PropertyValue\",\"name\":\"Pressure rating\",\"value\":\"PN16 \u2013 PN25 \u2013 PN40 \u00b7 ANSI Class 150 \u2013 Class 300\"},{\"@type\":\"PropertyValue\",\"name\":\"Set pressure range\",\"value\":\"0.02 to 10 barg depending on actuator and spring (up to 16 barg on request)\"},{\"@type\":\"PropertyValue\",\"name\":\"Maximum inlet pressure\",\"value\":\"10 barg (up to 16 barg on request)\"},{\"@type\":\"PropertyValue\",\"name\":\"Maximum differential pressure\",\"value\":\"16 bar for DN15 to DN50\"},{\"@type\":\"PropertyValue\",\"name\":\"Kv coefficient\",\"value\":\"From 3.5 m\u00b3\/h (DN15) to 115 m\u00b3\/h (DN100). 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If the installation needs overpressure protection, a safety valve must also be installed.\"}},{\"@type\":\"Question\",\"name\":\"Does it need an external control line?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"No, it comes with internal pressure sensing as standard. External sensing is only needed with steam or with liquids above 125 \u00b0C, connected at least 1 m from the inlet, or if specifically requested.\"}},{\"@type\":\"Question\",\"name\":\"Can it be used with steam?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Yes, with low-temperature steam. It must be ordered with external pressure sensing and a condensate pot, which protects the diaphragm from overheating. With a PTFE diaphragm and a condensate pot it works up to 180 \u00b0C.\"}},{\"@type\":\"Question\",\"name\":\"What set pressure does it accept?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"From 0.02 to 10 barg, depending on actuator and spring; up to 16 barg on request. 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