This hydraulic pressure relief valve will help us to control the upstream pressure

At Valfonta we have a wide catalogue of valves of all types: pressure relief valves, control valves, hydraulic pressure control valves… covering a wide range of possible applications.

In this post, we would like to talk more specifically about the hydraulic pressure relief valve model S3, a piece that serves to correctly maintain the upstream set pressure thanks to the setting pressure adjustment. If the upstream pressure exceeds the set pressure, the valve will gradually open at this increased pressure.

Features of the Valfonta Model S3 Hydraulic Pressure Relief Valve 

This is a hydraulic pressure relief valve composed of bronze, carbon steel and stainless steel. Its sealing type is Class IV (metal to metal) — Class VI (PTFE+GR seat). It works with an adjustment pressure of between 0.5 and 20 bar, and the maximum temperature allowed in the part is 0.7043 and 1.0619 -10 to 220º C 1.4408 – 30 to 220º C, and in the case of special seals up to 250º C.

This part complies with the ISO 9001 Quality System, Pressure Equipment Directive according to 2014/68/EU, and Atex Directive according to 2014/34/EU. 

válvula de alivio de presión hidráulica

Direct operation of the S3 valve 

As we have indicated at the beginning of the post, the main function of this relief valve is to maintain the set pressure upstream, due to its setting pressure adjustment. If the inlet pressure exceeds the set pressure, the valve opens gradually as the pressure rises.

It is important to note that this is not a safety valve and therefore an overpressure protection must be installed. This model is suitable for use with steam, gases, and liquids.

It should be noted that as a pressure valve, it must be protected against possible adverse influences such as dirt, moisture or extreme temperatures. When assembling it, its interior must be spotless and, very importantly, it is a type of part which must be installed by specialized personnel due to its complexity and the regulations to be followed.

On the other hand, we have to consider some pressure imbalances that can occur due to the passage of time and that are completely normal: a pressure that exceeds the set point, that the pressure falls below the set point, oscillations in the control, that the inlet pressure fluctuates and that the part emits a very high noise. All these small malfunctions are caused by use, but are quickly remedied depending on the type.

Still have doubts? Ask for all the information you need, as well as technical advice 

In Valfonta we are specialists in different valve models, our technical team will help you to choose your hydraulic pressure relief valve according to your needs. If you would like us to contact you to advise you on which type of valve and which model is best for you, just take a few seconds to fill in this form.

You can also call us on (+34) 93 37 208 88 or write to us at Let our specialists advise you!