SYR Variable Pressure Regulating Valve 32mm 

This is a high-quality pressure-regulating valve without a pressure relief valve.

Typically, a valve like this would be placed on the water feed line to step down the pressure.

The valve regulates pressure to 1.5 Bar to 6 Bar, but that is not what we wound in our test, have a look at the video.

The manufacturer rates it at a max incoming pressure of 25Bar.

The Valve is rated at 5800LPH (at 2m/s flow rate), with a pressure drop of 1.3 Bar at the maximum flow rate.

There are many products that regulate pressure, but not all of them have a pressure relief valve. The relief valve allows it to release water to reduce the pressure after the valve. This will typically be used to release pressure from water hammer when a tap is closed quickly or when pressure builds up due to the geyser heating up. This valve doesn't have one. Make sure you have one in your system.

It is very important to limit the pressure before filter systems and vessel systems to under 6 Bar, and to have them protected by a pressure relief valve or a pressurised buffer tank. 

Have a look at the video for a demonstration of how it works.