A Direct acting relief valve or Direct acting pressure relief valve (PRV) is a type of safety valve used to control or limit the pressure in a system; pressure might otherwise build up and create a process upset, instrument or equipment failure, or fire.

How to adjust Direct Acting Pressure Relief Valve?

Step 1: Loose the lock nut of the adjusting stem. Turn the adjusting screw counterclockwise until lowest outlet pressure.

Step 2: Adjusting the required set-point by turning adjusting stem clockwise and watch the pressure gauge to required upstream pressure.

Explode view of Direct Acting Pressure Relief Valve