G3/4 Pilot Operated Relief valve

Choosing a Pressure Relief Valve

Pressure relief valves are designed to keep hydraulic based machinery running safely – their main purpose is to protect systems from overpressure.

Certain applications require more specific types of pressure relief valves though. Choosing the right valve can be the difference between your machinery working safely or not.

As it isn’t a one size fits all situation with pressure relief valves, here are some factors you may want to consider when choosing the right valve for your hydraulic system.

Size and Type

The relief valve must be selected to suit the working flow and desired pressure of your system. There are 2 main types of relief valve, direct acting and pilot operated. The direct acting relief valve will limit the pressure in the system whilst the pilot operated type is used to control the pressure.

Pressure Limits

Obviously, the set pressure should not exceed the maximum working pressure of the system in question, so you need to know the limits of the system and ensure your valve is keeping the system below these limits.


Hy-Pro relief valves are available in 3 sizes, 40 L/min, 60 L/min and 100 L/min and rated at 250 Bar.  All can be supplied singly as cartridges or in 2 or 3 ported manifolds for line-mounting. They can also be supplied as pairs, installed in a 4 ported manifold for when there is a requirement to prevent shock loads in motors and cylinders.

We would always advise talking to our team if you’re unsure which kind of pressure relief valve you need – we have extensive experience designing valves for a myriad of applications, and will be able to advise exactly what part you need for your requirements.